近些年來，解決全球能源危機和碳排放问题的核心被公認為可以通過快速发展燃料电池(FC)和氢能源技术來取代传统的化石燃料。然而，燃料電池和電解池電池陰極板上固有的相對遲緩的氧还原反应(ORR)和析氢反应(HER)效率，以及昂贵金属白金的大量使用嚴重限制了燃料電池的普及商业化和氢能产业的发展。
本論文基於密度泛函理论（DFT）的第一原理計算提出並設計了一系列新型層疊式多元金属或金属氧化物構成的具有表面局部修飾或異質界面層嵌入式改性的核-壳型奈米结构觸媒。旨在改善觸媒陰極的氧還原或者析氫反應活性，增強觸媒的耐用性並减少貴金屬白金大規模使用。同時，這些觸媒結構設計也受到我們前期实验觀測結果的啟發，因此該理論設計和計算也被認為具有很高的實際操作性和可行性。
首先，我们提出了一个由Pt二聚体团簇修饰的Cocore@Pdshell构型(即Co@Pd-Pt2表面模型)，以深入探究嵌入表面的Pt二聚体对核殼型金属纳米觸媒ORR性能的影响。我们的结果表明，Pt二聚体调节了觸媒表面的局部物理-化学性质，製造了与O2、O*、H2O和OH相对应的不同表面吸附物的独特的吸附能(Eads)梯度分布，進而驱动了觸媒表面的ORR過程朝著特定的超高效路径進行。我們计算了ORR的两个子阶段的各自的反应势垒（活化能），并对Co@Pd-Pt2模型和其他對照組觸媒进行了深入的电荷分佈/轉移分析，最終证实了Pt二聚体和邻近的Pd/Co金屬產生的局部協同效應對ORR活性的催化提升效果。其中，Co@Pd-Pt2觸媒模型表面修饰的Pt二聚体可被看作是电荷转移中心，它为Pd/Co部分与外部ORR中间体之间的电荷交换建立了一个超通道，因此顯著提升了氧化還原效率。
接著，基于上述對表面Pt二聚体修飾Co@Pd核-殼觸媒的ORR活性研究的结果，我们進一步全面地研究了表面修飾的Pt簇尺寸（从单原子級修飾到表面完全覆盖）对CoCore-PdShell奈米结构的ORR效率的影響。结果表明，随着核殼結構表面Pt修飾团簇尺寸由纳米級减小至亚纳米級，表面Pt-Pd界面区的局部协同效应逐渐增强，导致了从內層金屬Co到最外层金屬Pt的定向可調控的电荷转移机制，从而實現了對中間產物吸附原子氧的表面结合强度的優化，實現了以最小Pt使用量以及超高Pt原子利用率(即Pt1至Pt3)來ORR性能的逐步提高。我们所提出的Co@Pd-Ptn三元系统的触媒表面Pt装饰尺寸和与之相对的ORR活性的这种依赖关系有机会成为对于有序异质奈米触媒制备的精确指南，以实现低Pt使用、高能效和绿色经济。
第三，根据我们以前的实验观察，为析氢反应（HER）研究建立了一个在构建的NiO2-to-Pd异质层叠奈米结构内界面进行原子级Ni团簇插层的新型无白金触媒，即NiO2-Nid-Pd触媒系统。研究结果表明，所提出的七个NiO2-Nid-Pd模型系统的吸附能和氢原子的吉布斯自由能，即Eads-H*和ΔGH*，成功预测了各自模型的HER活性优于对照组的传统Pd(111)和标杆Pt(111)触媒。过渡态计算进一步证明了4-Ni四角形内部掺杂的NiO2-Ni4-Pd模型在提高HER动力学方面达到了NiO2-Nid-Pd系列中上层Pd原子层内Ni掺杂的阈值。
最后，依据我们之前在相关实验中所观察到的现象，推理建立了金属铱（Ir）的氧化物（IrOx）团簇装饰的Co3O4@Pd核-壳式结构触媒模型（即CPI-1、CPI-3和CPI-7三种模型）。以CP1-1模型为例，计算结果充分显示出锚定在触媒表面的IrO3单体氧化物团簇显著调节了整个模型表面的关键几种吸附物（O2、O*、H2O和OH）的吸附能力（Eads）。这使得触媒表面不同的吸附物种产生了不同的吸附能分布趋势，具体而言，使得靠近IrO3的区域更适合O2的解离，而远离IrO3的Pd表面区域则更适合后续过程中中间产物O*的还原。更深入的电子局域函数（ELF）计算揭示了在原子级尺度的IrO3团簇周围形成强大的负电场的限域效应，其排斥带负电的O*和OH*和促进了O*的迁移，并促进近IrO3区域的活性位点不断恢复/再生以进行ORR。以上结果使得表现最优的CPI-1型触媒具有极为独特的ORR机理，即促使ORR的各种中间反应步骤可在触媒表面不同分区域同时进行进而产生了区域协同合作机制，因此，IrO3单体团簇在Co3O4@Pd核-壳表面作为单一纳米粒子反应器赋予触媒超高的ORR性能是合理的。

The crux of global energy and carbon-emission issues is the replacement of traditional fossil fuels by burgeoning fuel cells (FCs) as well as hydrogen energy technologies. However, the inherently sluggish oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) at the cathode and the massive utilization of costly metal platinum restrict the large-scale commercialization of FCs and the hydrogen energy industry.
In this thesis, a series of catalyst designs of stacked multimetal/metaloxide core-shell-type structure with local modification of surface decoration or interface intercalation is proposed, aiming at improving the ORR/HER activity, increasing the durability and reducing the Pt usage based on the density functional theory (DFT) calculations, where some ideas are sparked from our previous experimental observation and thus having high feasibility of experimental preparation.
First, we proposed a Cocore@Pdshell configuration decorated with Pt-dimer cluster (i.e., Co@Pd-Pt2 model surface) to thoroughly explore the effect of embedded Pt dimer on the ORR performance for the metallic nanocatalyst. Our results exhibit that the Pt dimer tunes the local physical and chemical properties of the catalyst surface to generate a unique gradient distribution of adsorption energy (Eads) corresponding to O2, O*, H2O and OH, thus driving the ORR along a specific efficient pathway. The calculated reaction barriers of the two ORR sub-stages and the deep-going charge analysis for the Co@Pd-Pt2 and other reference catalysts confirm a local catalytic collaboration between the Pt dimer and neighboring Pd/Co on the prominent ORR activity. The decorated Pt dimer in the Co@Pd-Pt2 system is believed to serve as a charge transfer hub to build a hyper channel for charge exchange between Pd/Co and external ORR-intermediates.
Based on the above result on the Pt dimer-decorated Co@Pd catalyst, we then comprehensively study the effect of the decorated Pt-cluster size (from single-atom to full coverage) on the ORR efficiency of the Cocore-Pdshell structure. Our results reveal that there is a gradually enhancing synergetic effect on the Pt-Pd interface domains of the surface with the Pt cluster size reduced from nanometers to sub-nanometers, which induces an oriented and tunable charge transfer mechanism from deep-Co to outermost-Pt, thereby optimizing the bonding strength of oxygen and achieving the progressively improved ORR performance with minimum Pt usage and ultrahigh Pt atom utilization (i.e., Pt1 to Pt3). Such a dependency between the surface decoration size and ORR activity of the proposed Co@Pd-Ptn system can be a precise guideline for the ordered heterogeneous nanocatalysts synthesis toward low Pt, high efficiency and green economy.
Thirdly, a novel Pt-free catalyst consisting of interfacial atomic Ni ensemble intercalation in a NiO2-to-Pd heterostructure, i.e., the NiO2‒Nid‒Pd systems, is modeled for the HER investigation according to our previous experimental observations. Our results indicate that the adsorption energy and Gibbs free energy of atomic hydrogen, i.e., Eads-H* and ΔGH*, of the proposed seven NiO2‒Nid‒Pd systems forecast the superior HER activity to Pd(111) and benchmark Pt(111). The transition-state calculations prove the 4-Ni tetragon internally intercalated NiO2‒Ni4‒Pd catalyst is the Ni doping threshold in Pd-layers of the NiO2‒Nid‒Pd series in terms of the HER kinetic improvement. Deep insight into the charge distribution reveals that the optimal HER performance observed on the representative NiO2‒Ni4‒Pd is attributed to the synergistic effect triggered by ligand and strain effect from the internally doped Ni tetragon and its surrounding Pd atoms, leading to the electron disequilibrium on the local domain of the surface with invariable the atomic arrangement of the surface.
Finally, the Ir oxide cluster-decorated Co3O4@Pd core-shell catalyst (namely, the CPI-1, CPI-3 and CPI-7 models) are developed based on our experimental observation. The results provide concrete evidence that the anchored IrO3 monomer is observed to regulate the Eads of the key adsorbates (O2, O*, H2O and OH) of the entire surface, thereby, the differentiated Eads-distribution for different absorbates on catalyst surface were generated, which make the near-IrO3-zone more suitable for O2 dissociation and the far-off Pd-zone more preferable for subsequent O* reduction. In-depth electron localization function (ELF) reveal a confinement effect developing a strong negative field around the atomic IrO3 to repel the negatively charged O* and OH*, facilitate O* relocation and regenerate the active sites in the near-IrO3-zone for ORR. Such a scenario endows the optimal CPI-1 catalyst a unique ORR mechanism with the simultaneous collaboration of the various intermediate steps in ORR across the various segmented surface zones, therefore, rationalizing the IrO3 monomer as a single nanoparticle reactor with ultra-high performance in ORR.

TABLE OF CONTENTS

ACKNOWLEDGMENTS i
中文摘要 ii
ABSTRACT v
LIST OF SYMBOLS AND ABBREVIATION xii
LIST OF FIGURES xiv
LIST OF TABLES xxiii
CHAPTER 1 INTRODUCTION AND LITERATURE REVIEW 1
1.1 Background 1
1.2 Water electrolysis 2
1.3 Fuel cell system 4
1.3.1 A brief history of fuel cell technologies 4
1.3.2 The working principle of fuel cell 6
1.4 The HER/ORR catalysts 9
1.4.1 The HER and ORR mechanisms 9
1.4.2 Platinum catalyst 14
1.4.3 Palladium-based catalysts 16
1.5 Catalyst improvement strategies 18
1.5.1 Alloying with non-noble metals 19
1.5.2 Constructing core-shell structure 21
1.5.3 Controlling catalyst size 26
1.6 Research idea and strategy of this topic 28
1.6.1 Innovative ideas of this research 28
1.6.2 Objectives of this research 31
CHAPTER 2 RESEARCH METHODOLOGY 34
2.1 Schrödinger equation 34
2.2 Born-Oppenheimer adiabatic approximation 35
2.3 Single electron approximation 35
2.4 Density functional theory 37
2.4.1 Hohenberg-Kohn theorem 38
2.4.2 Kohn-Sham equation 40
2.4.3 Exchange-Correlation functional 41
2.4.4 Local Density Approximation & Generalized Gradient Approximation 42
2.4.5 Periodic boundary condition 43
2.4.6 Plane Waves Basis sets 45
2.4.6 Pseudopotentials 45
2.4.7 Vienna Ab Initio Simulation Package 46
CHAPTER 3 PT DIMER OPENS THE OPTIMAL CHANNEL ON CO-PD CORE-SHELL NANOCATALYSTS FOR ORR 47
3.1 Introduction 47
3.2 Computational details 49
3.3 Result and discussions 51
3.3.1 Determination of configurations and stabilities 51
3.3.2 Adsorption energy distribution induced efficient ORR paths 53
3.3.3 Reaction barriers 61
3.3.4 Charge transfer mechanism 67
3.4 Conclusions 72
CHAPTER 4 OPTIMUM DIMENSION OF ATOMIC PT CLUSTERS ON CO@PD NANOPARTICLE SURFACE FOR ORR 74
4.1 Introduction 74
4.2 Computational details 77
4.3 Result and discussions 79
4.3.1 Stability of the proposed model structures 79
4.3.2 Adsorption capacity of O2 and atomic O 81
4.3.3 Reaction barriers 91
4.3.4 Charge transfer mechanism induced by the synergetic effect 100
4.4 Conclusions 112
CHAPTER 5 INTERFACIAL ATOMIC NI ENSEMBLE INTERCALATION IN A NIO2-TO-PD STRUCTURE TRIGGERS SUPERIOR HER 114
5.1 Introduction 114
5.2 Computational details 117
5.3 Result and discussions 120
5.3.1 Determination of surface model configurations 120
5.3.2 Adsorption characteristics of atomic hydrogen 123
5.3.3 HER mechanism of the NiO2‒Nid‒Pd model catalysts 134
5.3.4 Charge transfer mechanism of the NiO2‒Nid‒Pd nanocatalyst 141
5.4 Conclusions 147
CHAPTER 6 SINGLE IR-OXIDE CLUSTER DECORATED ON COOX@PD NANOCATALYST SURFACE FOR ORR 149
6.1 Introduction 149
6.2 Computational details 153
6.3 Result and discussions 155
6.3.1 Determination of the three surface model configurations 155
6.3.2 Effect of IrO3m cluster on the adsorption energy distribution 159
6.3.3 ORR mechanism of the CPI nanocatalysts 165
6.4 Conclusions 171
CHAPTER 7 CONCLUSION AND OUTLOOK 173
7.1 Conclusion 173
7.2 Outlook 176
Reference 179
PUBLICATIONS 201

Reference
1. Turner, J. A. Sustainable Hydrogen Production. Science 305, 972–974 (2004).
2. Chu, S. & Majumdar, A. Opportunities and challenges for a sustainable energy future. Nature 488, 294–303 (2012).
3. Potočnik, J. Renewable Energy Sources and the Realities of Setting an Energy Agenda. Science 315, 810–811 (2007).
4. Mueller-Langer, F., Tzimas, E., Kaltschmitt, M. & Peteves, S. Techno-economic assessment of hydrogen production processes for the hydrogen economy for the short and medium term. Int. J. Hydrog. Energy 32, 3797–3810 (2007).
5. Bockris, J. O. The origin of ideas on a Hydrogen Economy and its solution to the decay of the environment. Int. J. Hydrog. Energy 27, 731–740 (2002).
6. Jiao, Y., Zheng, Y., Jaroniec, M. & Zhang Qiao, S. Design of electrocatalysts for oxygen- and hydrogen-involving energy conversion reactions. Chem. Soc. Rev. 44, 2060–2086 (2015).
7. Li, J. & Zheng, G. One-Dimensional Earth-Abundant Nanomaterials for Water-Splitting Electrocatalysts. Adv. Sci. 4, 1600380 (2017).
8. Licht, S. et al. Over 18% solar energy conversion to generation of hydrogen fuel; theory and experiment for efficient solar water splitting. Int. J. Hydrog. Energy 26, 653–659 (2001).
9. Wang, B., Li, Y. & Ren, N. Biohydrogen from molasses with ethanol-type fermentation: Effect of hydraulic retention time. Int. J. Hydrog. Energy 38, 4361–4367 (2013).
10. Seh, Z. W. et al. Combining theory and experiment in electrocatalysis: Insights into materials design. Science 355, (2017).
11. Xu, Y., Kraft, M. & Xu, R. Metal-free carbonaceous electrocatalysts and photocatalysts for water splitting. Chem. Soc. Rev. 45, 3039–3052 (2016).
12. Duan, J., Chen, S. & Zhao, C. Ultrathin metal-organic framework array for efficient electrocatalytic water splitting. Nat. Commun. 8, 15341 (2017).
13. Rossmeisl, J., Qu, Z.-W., Zhu, H., Kroes, G.-J. & Nørskov, J. K. Electrolysis of water on oxide surfaces. J. Electroanal. Chem. 607, 83–89 (2007).
14. Holladay, J. D., Hu, J., King, D. L. & Wang, Y. An overview of hydrogen production technologies. Catal. Today 139, 244–260 (2009).
15. Safizadeh, F., Ghali, E. & Houlachi, G. Electrocatalysis developments for hydrogen evolution reaction in alkaline solutions – A Review. Int. J. Hydrog. Energy 40, 256–274 (2015).
16. Santos, D. M. F., Sequeira, C. A. C. & Figueiredo, J. L. Hydrogen production by alkaline water electrolysis. Quím. Nova 36, 1176–1193 (2013).
17. Winter, M. & Brodd, R. J. What Are Batteries, Fuel Cells, and Supercapacitors? Chem. Rev. 104, 4245–4270 (2004).
18. Debe, M. K. Electrocatalyst approaches and challenges for automotive fuel cells. Nature 486, 43–51 (2012).
19. Ahmed, S. & Krumpelt, M. Hydrogen from hydrocarbon fuels for fuel cells. Int. J. Hydrog. Energy 26, 291–301 (2001).
20. Wang, Y., Chen, K. S., Mishler, J., Cho, S. C. & Adroher, X. C. A review of polymer electrolyte membrane fuel cells: Technology, applications, and needs on fundamental research. Appl. Energy 88, 981–1007 (2011).
21. Joon, K. Fuel cells – a 21st century power system. J. Power Sources 71, 12–18 (1998).
22. Fuel Cell Industry Review 2019 - The Year of the Gigawatt. E4tech https://www.e4tech.com/news/2018-fuel-cell-industry-review-2019-the-year-of-the-gigawatt.php (2020).
23. Grimes, P. Historical pathways for fuel cells. The new electric century. in Fifteenth Annual Battery Conference on Applications and Advances (Cat. No.00TH8490) 41–45 (2000). doi:10.1109/BCAA.2000.838369.
24. Appleby, A. J. From Sir William Grove to today: fuel cells and the future. J. Power Sources 29, 3–11 (1990).
25. Andújar, J. M. & Segura, F. Fuel cells: History and updating. A walk along two centuries. Renew. Sustain. Energy Rev. 13, 2309–2322 (2009).
26. Bidault, F., Brett, D. J. L., Middleton, P. H. & Brandon, N. P. Review of gas diffusion cathodes for alkaline fuel cells. J. Power Sources 187, 39–48 (2009).
27. Baur, E. & Preis, H. Über Brennstoff-Ketten mit Festleitern. Z. Für Elektrochem. Angew. Phys. Chem. 43, 727–732 (1937).
28. Stone, C. & Morrison, A. E. From curiosity to “power to change the world®”. Solid State Ion. 152–153, 1–13 (2002).
29. Lin, B. Y. S., Kirk, D. W. & Thorpe, S. J. Performance of alkaline fuel cells: A possible future energy system? J. Power Sources 161, 474–483 (2006).
30. Sharaf, O. Z. & Orhan, M. F. An overview of fuel cell technology: Fundamentals and applications. Renew. Sustain. Energy Rev. 32, 810–853 (2014).
31. Baldauf, M. & Preidel, W. Status of the development of a direct methanol fuel cell. J. Power Sources 84, 161–166 (1999).
32. M., S. N., Tremblay, O. & Dessaint, L.-A. A generic fuel cell model for the simulation of fuel cell vehicles. in 2009 IEEE Vehicle Power and Propulsion Conference 1722–1729 (2009). doi:10.1109/VPPC.2009.5289692.
33. Ramani, V., Kunz, H. R. & Fenton, J. M. The Polymer Electrolyte Fuel Cell. Electrochem. Soc. Interface 4 (2004).
34. Das, V. et al. Recent advances and challenges of fuel cell based power system architectures and control – A review. Renew. Sustain. Energy Rev. 73, 10–18 (2017).
35. Nørskov, J. K. et al. Origin of the Overpotential for Oxygen Reduction at a Fuel-Cell Cathode. J. Phys. Chem. B 108, 17886–17892 (2004).
36. Larminie, J. & Dicks, A. Fuel Cell Systems Analysed. in Fuel Cell Systems Explained 369–389 (John Wiley & Sons, Ltd, 2013). doi:10.1002/9781118878330.ch11.
37. Efficiency and Open-Circuit Voltage. in Fuel Cell Systems Explained 27–41 (John Wiley & Sons, Ltd, 2018). doi:10.1002/9781118706992.ch2.
38. Gasteiger, H. A. & Marković, N. M. Just a Dream—or Future Reality? Science 324, 48–49 (2009).
39. Ruqia, B. & Choi, S.-I. Pt and Pt–Ni(OH)2 Electrodes for the Hydrogen Evolution Reaction in Alkaline Electrolytes and Their Nanoscaled Electrocatalysts. ChemSusChem 11, 2643–2653 (2018).
40. Nørskov, J. K. et al. Trends in the Exchange Current for Hydrogen Evolution. J. Electrochem. Soc. 152, J23 (2005).
41. Ge, X. et al. Oxygen Reduction in Alkaline Media: From Mechanisms to Recent Advances of Catalysts. ACS Catal. 5, 4643–4667 (2015).
42. Anastasijević, N. A., Vesović, V. & Adžić, R. R. Determination of the kinetic parameters of the oxygen reduction reaction using the rotating ring-disk electrode: Part I. Theory. J. Electroanal. Chem. Interfacial Electrochem. 229, 305–316 (1987).
43. Xu, Y., Ruban, A. V. & Mavrikakis, M. Adsorption and Dissociation of O2 on Pt−Co and Pt−Fe Alloys. J. Am. Chem. Soc. 126, 4717–4725 (2004).
44. Metals close to the border between metals and nonmetals. Wikipedia (2021).
45. Gasteiger, H. A., Kocha, S. S., Sompalli, B. & Wagner, F. T. Activity benchmarks and requirements for Pt, Pt-alloy, and non-Pt oxygen reduction catalysts for PEMFCs. Appl. Catal. B Environ. 56, 9–35 (2005).
46. Ruban, A., Hammer, B., Stoltze, P., Skriver, H. L. & Nørskov, J. K. Surface electronic structure and reactivity of transition and noble metals1Communication presented at the First Francqui Colloquium, Brussels, 19–20 February 1996.1. J. Mol. Catal. Chem. 115, 421–429 (1997).
47. Wang, Y. & Balbuena, P. B. Design of Oxygen Reduction Bimetallic Catalysts:  Ab-Initio-Derived Thermodynamic Guidelines. J. Phys. Chem. B 109, 18902–18906 (2005).
48. Hammer, B. & Nørskov, J. K. Electronic factors determining the reactivity of metal surfaces. Surf. Sci. 343, 211–220 (1995).
49. Greeley, J., Nørskov, J. K. & Mavrikakis, M. Electronic Structure and Catalysis on Metal Surfaces. Annu. Rev. Phys. Chem. 53, 319–348 (2002).
50. Chen, A. & Holt-Hindle, P. Platinum-Based Nanostructured Materials: Synthesis, Properties, and Applications. Chem. Rev. 110, 3767–3804 (2010).
51. Abbas, M. A. & Bang, J. H. Rising Again: Opportunities and Challenges for Platinum-Free Electrocatalysts. Chem. Mater. 27, 7218–7235 (2015).
52. Zhang, S. et al. A review of platinum-based catalyst layer degradation in proton exchange membrane fuel cells. J. Power Sources 194, 588–600 (2009).
53. Subbaraman, R. et al. Trends in activity for the water electrolyser reactions on 3 d M(Ni,Co,Fe,Mn) hydr(oxy)oxide catalysts. Nat. Mater. 11, 550–557 (2012).
54. Wang, W., Wang, Z., Wang, J., Zhong, C.-J. & Liu, C.-J. Highly Active and Stable Pt–Pd Alloy Catalysts Synthesized by Room-Temperature Electron Reduction for Oxygen Reduction Reaction. Adv. Sci. 4, 1600486 (2017).
55. Shao, M., Liu, P., Zhang, J. & Adzic, R. Origin of Enhanced Activity in Palladium Alloy Electrocatalysts for Oxygen Reduction Reaction. J. Phys. Chem. B 111, 6772–6775 (2007).
56. Strasser, P. et al. Lattice-strain control of the activity in dealloyed core–shell fuel cell catalysts. Nat. Chem. 2, 454–460 (2010).
57. Kitchin, J. R., Nørskov, J. K., Barteau, M. A. & Chen, J. G. Modification of the surface electronic and chemical properties of Pt(111) by subsurface 3d transition metals. J. Chem. Phys. 120, 10240–10246 (2004).
58. Benck, J. D., Hellstern, T. R., Kibsgaard, J., Chakthranont, P. & Jaramillo, T. F. Catalyzing the Hydrogen Evolution Reaction (HER) with Molybdenum Sulfide Nanomaterials. ACS Catal. 4, 3957–3971 (2014).
59. Cong, P. et al. High-Throughput Synthesis and Screening of Combinatorial Heterogeneous Catalyst Libraries. Angew. Chem. Int. Ed. 38, 483–488 (1999).
60. Recent Progress in Cobalt‐Based Heterogeneous Catalysts for Electrochemical Water Splitting - Wang - 2016 - Advanced Materials - Wiley Online Library. https://onlinelibrary.wiley.com/doi/full/10.1002/adma.201502696.
61. Gewirth, A. A., Varnell, J. A. & DiAscro, A. M. Nonprecious Metal Catalysts for Oxygen Reduction in Heterogeneous Aqueous Systems. Chem. Rev. 118, 2313–2339 (2018).
62. Wang, L., Holewinski, A. & Wang, C. Prospects of Platinum-Based Nanostructures for the Electrocatalytic Reduction of Oxygen. ACS Catal. 8, 9388–9398 (2018).
63. Greeley, J. et al. Alloys of platinum and early transition metals as oxygen reduction electrocatalysts. Nat. Chem. 1, 552–556 (2009).
64. Greeley, J. & Mavrikakis, M. Alloy catalysts designed from first principles. Nat. Mater. 3, 810–815 (2004).
65. Li, J. et al. Ni@Pd/PEI–rGO stack structures with controllable Pd shell thickness as advanced electrodes for efficient hydrogen evolution. J. Mater. Chem. A 3, 11261–11268 (2015).
66. Jana, R., Bhim, A., Bothra, P., Pati, S. K. & Peter, S. C. Electrochemical Dealloying of PdCu3 Nanoparticles to Achieve Pt-like Activity for the Hydrogen Evolution Reaction. ChemSusChem 9, 2922–2927 (2016).
67. Zhao, Z. et al. Pt-Based Nanocrystal for Electrocatalytic Oxygen Reduction. Adv. Mater. 31, 1808115 (2019).
68. Yang, H. Platinum-Based Electrocatalysts with Core–Shell Nanostructures. Angew. Chem. Int. Ed. 50, 2674–2676 (2011).
69. Esparza, R. et al. Study of PtPd Bimetallic Nanoparticles for Fuel Cell Applications. Mater. Res. 20, 1193–1200 (2017).
70. Medford, A. J. et al. From the Sabatier principle to a predictive theory of transition-metal heterogeneous catalysis. J. Catal. 328, 36–42 (2015).
71. Ruban, A., Hammer, B., Stoltze, P., Skriver, H. L. & Nørskov, J. K. Surface electronic structure and reactivity of transition and noble metals. 9 (1997).
72. Mavrikakis, M., Hammer, B. & Nørskov, J. K. Effect of Strain on the Reactivity of Metal Surfaces. Phys. Rev. Lett. 81, 2819–2822 (1998).
73. Hammer, B. & Nørskov, J. K. Theoretical surface science and catalysis—calculations and concepts. in Advances in Catalysis vol. 45 71–129 (Elsevier, 2000).
74. Li, H., Shin, K. & Henkelman, G. Effects of ensembles, ligand, and strain on adsorbate binding to alloy surfaces. J. Chem. Phys. 149, 174705 (2018).
75. Takehiro, N., Liu, P., Bergbreiter, A., K. Nørskov, J. & Jürgen Behm, R. Hydrogen adsorption on bimetallic PdAu(111) surface alloys: minimum adsorption ensemble, ligand and ensemble effects, and ensemble confinement. Phys. Chem. Chem. Phys. 16, 23930–23943 (2014).
76. Tsai, H.-C. et al. DFT Study of Oxygen Reduction Reaction on Os/Pt Core–Shell Catalysts Validated by Electrochemical Experiment. ACS Catal. 5, 1568–1580 (2015).
77. Chen, T.-Y. et al. Self-aligned synthesis of a NiPt-alloycore@Ptshell nanocrystal with contrivable heterojunction structure and oxygen reduction activity. CrystEngComm 18, 5860–5868 (2016).
78. Chen, H.-Y. T. et al. Heterogeneous Cu–Pd binary interface boosts stability and mass activity of atomic Pt clusters in the oxygen reduction reaction. Nanoscale 9, 7207–7216 (2017).
79. Zhuang, Y. et al. Atomic scale Pt decoration promises oxygen reduction properties of Co@Pd nanocatalysts in alkaline electrolytes for 310k redox cycles. Sustain. Energy Fuels 2, 946–957 (2018).
80. Xiong, L. & Manthiram, A. Effect of Atomic Ordering on the Catalytic Activity of Carbon Supported PtM (M = Fe , Co, Ni, and Cu) Alloys for Oxygen Reduction in PEMFCs. J. Electrochem. Soc. 152, A697–A703 (2005).
81. Xiang, T. et al. Thickness-tunable core–shell Co@Pt nanoparticles encapsulated in sandwich-like carbon sheets as an enhanced electrocatalyst for the oxygen reduction reaction. J. Mater. Chem. A 6, 21396–21403 (2018).
82. Lile, J. R. D., Lee, S. Y., Kim, H.-J., Pak, C. & Lee, S. G. First-principles study of the effect of compressive strain on oxygen adsorption in Pd/Ni/Cu-alloy-core@Pd/Ir-alloy-shell catalysts. New J. Chem. 43, 8195–8203 (2019).
83. Shao, M., Peles, A. & Shoemaker, K. Electrocatalysis on Platinum Nanoparticles: Particle Size Effect on Oxygen Reduction Reaction Activity. Nano Lett. 11, 3714–3719 (2011).
84. Liu, Y., Zhang, L., Willis, B. G. & Mustain, W. E. Importance of Particle Size and Distribution in Achieving High-Activity, High-Stability Oxygen Reduction Catalysts. ACS Catal. 5, 1560–1567 (2015).
85. Tripković, V., Cerri, I., Bligaard, T. & Rossmeisl, J. The Influence of Particle Shape and Size on the Activity of Platinum Nanoparticles for Oxygen Reduction Reaction: A Density Functional Theory Study. Catal. Lett. 144, 380–388 (2014).
86. Zhang, R., Xue, M., Wang, B., Ling, L. & Fan, M. C2H2 Selective Hydrogenation over the M@Pd and M@Cu (M = Au, Ag, Cu, and Pd) Core–Shell Nanocluster Catalysts: The Effects of Composition and Nanocluster Size on Catalytic Activity and Selectivity. J. Phys. Chem. C 123, 16107–16117 (2019).
87. Wang, A., Li, J. & Zhang, T. Heterogeneous single-atom catalysis. Nat. Rev. Chem. 2, 65–81 (2018).
88. Yang, X.-F. et al. Single-Atom Catalysts: A New Frontier in Heterogeneous Catalysis. Acc. Chem. Res. 46, 1740–1748 (2013).
89. Fei, H. et al. Atomic cobalt on nitrogen-doped graphene for hydrogen generation. Nat. Commun. 6, 8668 (2015).
90. Fernández, J. L., Walsh, D. A. & Bard, A. J. Thermodynamic Guidelines for the Design of Bimetallic Catalysts for Oxygen Electroreduction and Rapid Screening by Scanning Electrochemical Microscopy. M−Co (M:  Pd, Ag, Au). J. Am. Chem. Soc. 127, 357–365 (2005).
91. Dai, S. et al. Platinum-trimer decorated cobalt-palladium core-shell nanocatalyst with promising performance for oxygen reduction reaction. Nat. Commun. 10, 1–10 (2019).
92. Liu, L. & Corma, A. Metal Catalysts for Heterogeneous Catalysis: From Single Atoms to Nanoclusters and Nanoparticles. Chem. Rev. 118, 4981–5079 (2018).
93. Rh single atoms on TiO 2 dynamically respond to reaction conditions by adapting their site | Nature Communications. https://www.nature.com/articles/s41467-019-12461-6.
94. Lu, Y. & Chen, W. Sub-nanometre sized metal clusters: from synthetic challenges to the unique property discoveries. Chem. Soc. Rev. 41, 3594–3623 (2012).
95. Tyo, E. C. & Vajda, S. Catalysis by clusters with precise numbers of atoms. Nat. Nanotechnol. 10, 577–588 (2015).
96. Schmid, G. et al. Current and future applications of nanoclusters. Chem. Soc. Rev. 28, 179–185 (1999).
97. Yang, H. et al. Atomic-scale Pt clusters decorated on porous α-Ni(OH)2 nanowires as highly efficient electrocatalyst for hydrogen evolution reaction. Sci. China Mater. 60, 1121–1128 (2017).
98. Bratlie, K. M., Lee, H., Komvopoulos, K., Yang, P. & Somorjai, G. A. Platinum nanoparticle shape effects on benzene hydrogenation selectivity. Nano Lett. 7, 3097–3101 (2007).
99. Zhuang, Y. et al. Pt3 clusters-decorated Co@Pd and Ni@Pd model core–shell catalyst design for the oxygen reduction reaction: a DFT study. J. Mater. Chem. A 6, 23326–23335 (2018).
100. García-Muelas, R. & López, N. Statistical learning goes beyond the d -band model providing the thermochemistry of adsorbates on transition metals. Nat. Commun. 10, 1–7 (2019).
101. Hohenberg, P. & Kohn, W. Inhomogeneous Electron Gas. Phys. Rev. 136, B864–B871 (1964).
102. Kohn, W. & Sham, L. J. Self-Consistent Equations Including Exchange and Correlation Effects. Phys. Rev. 140, A1133–A1138 (1965).
103. Jones, R. O. & Gunnarsson, O. The density functional formalism, its applications and prospects. Rev. Mod. Phys. 61, 689–746 (1989).
104. Perdew, J. P. et al. Atoms, molecules, solids, and surfaces: Applications of the generalized gradient approximation for exchange and correlation. Phys. Rev. B 46, 6671–6687 (1992).
105. Lee, C., Yang, W. & Parr, R. G. Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. Phys. Rev. B 37, 785–789 (1988).
106. Becke, A. D. Density-functional exchange-energy approximation with correct asymptotic behavior. Phys. Rev. A 38, 3098–3100 (1988).
107. Perdew, J. P, Burke, K. & Ernzerhof, M. Generalized Gradient Approximation Made Simple. Phys. Rev. Lett. 77, 3865–3868 (1996).
108. Chadi, D. J. & Cohen, M. L. Special Points in the Brillouin Zone. Phys. Rev. B 8, 5747–5753 (1973).
109. Monkhorst, H. J. & Pack, J. D. Special points for Brillouin-zone integrations. Phys. Rev. B 13, 5188–5192 (1976).
110. Hamann, D. R., Schlüter, M. & Chiang, C. Norm-Conserving Pseudopotentials. Phys. Rev. Lett. 43, 1494–1497 (1979).
111. Vanderbilt, D. Soft self-consistent pseudopotentials in a generalized eigenvalue formalism. Phys. Rev. B 41, 7892–7895 (1990).
112. Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50, 17953–17979 (1994).
113. Kresse, G. & Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169–11186 (1996).
114. Kresse, G. & Furthmüller, J. Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput. Mater. Sci. 6, 15–50 (1996).
115. Liu, M., Zhao, Z., Duan, X. & Huang, Y. Nanoscale Structure Design for High-Performance Pt-Based ORR Catalysts. Adv. Mater. 31, 1802234 (2019).
116. Shao, M., Chang, Q., Dodelet, J.-P. & Chenitz, R. Recent Advances in Electrocatalysts for Oxygen Reduction Reaction. Chem. Rev. 116, 3594–3657 (2016).
117. Nie, Y., Li, L. & Wei, Z. Recent advancements in Pt and Pt-free catalysts for oxygen reduction reaction. Chem. Soc. Rev. 44, 2168–2201 (2015).
118. Enhancing Oxygen Reduction Activity of Pt‐based Electrocatalysts: from Theoretical Mechanisms to Practical Methods - Ma - - Angewandte Chemie International Edition - Wiley Online Library. https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202003654.
119. Effects of ensembles, ligand, and strain on adsorbate binding to alloy surfaces: The Journal of Chemical Physics: Vol 149, No 17. https://aip.scitation.org/doi/full/10.1063/1.5053894.
120. Nilekar, A. U. & Mavrikakis, M. Improved oxygen reduction reactivity of platinum monolayers on transition metal surfaces. Surf. Sci. 602, L89–L94 (2008).
121. Kresse, G. & Hafner, J. Ab initio molecular dynamics for liquid metals. Phys. Rev. B 47, 558–561 (1993).
122. Kresse, G. & Furthmüller, J. Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput. Mater. Sci. 6, 15–50 (1996).
123. Perdew, J. P., Burke, K. & Wang, Y. Generalized gradient approximation for the exchange-correlation hole of a many-electron system. Phys. Rev. B 54, 16533–16539 (1996).
124. Henkelman, G. & Jónsson, H. Improved tangent estimate in the nudged elastic band method for finding minimum energy paths and saddle points. J. Chem. Phys. 113, 9978–9985 (2000).
125. Henkelman, G., Uberuaga, B. P. & Jónsson, H. A climbing image nudged elastic band method for finding saddle points and minimum energy paths. J. Chem. Phys. 113, 9901–9904 (2000).
126. Sharma, M. et al. Work function-tailored graphene via transition metal encapsulation as a highly active and durable catalyst for the oxygen reduction reaction. Energy Environ. Sci. 12, 2200–2211 (2019).
127. Henkelman, G., Arnaldsson, A. & Jónsson, H. A fast and robust algorithm for Bader decomposition of charge density. Comput. Mater. Sci. 36, 354–360 (2006).
128. Bader, R. F. W. Atoms in Molecules: A Quantum Theory. (Oxford University Press, 1994).
129. Demirdöven, N. & Deutch, J. Hybrid Cars Now, Fuel Cell Cars Later. Science 305, 974–976 (2004).
130. Seh, Z. W. et al. Combining theory and experiment in electrocatalysis: Insights into materials design. Science 355, eaad4998 (2017).
131. Kitchin, J. R., Nørskov, J. K., Barteau, M. A. & Chen, J. G. Role of strain and ligand effects in the modification of the electronic and chemical properties of bimetallic surfaces. Phys. Rev. Lett. 93, 156801 (2004).
132. Pan, Y., Zhang, C., Liu, Z., Chen, C. & Li, Y. Structural Regulation with Atomic-Level Precision: From Single-Atomic Site to Diatomic and Atomic Interface Catalysis. Matter 2, 78–110 (2020).
133. Chen, T.-Y. et al. Gold atomic clusters extracting the valence electrons to shield the carbon monoxide passivation on near-monolayer core–shell nanocatalysts in methanol oxidation reactions. Phys. Chem. Chem. Phys. 17, 15131–15139 (2015).
134. Li, H. et al. Collaboration between a Pt-dimer and neighboring Co–Pd atoms triggers efficient pathways for oxygen reduction reaction. Phys. Chem. Chem. Phys. 23, 1822–1834 (2021).
135. Rossmeisl, J., S. Karlberg, G., Jaramillo, T. & K. Nørskov, J. Steady state oxygen reduction and cyclic voltammetry. Faraday Discuss. 140, 337–346 (2009).
136. Rossmeisl, J., Logadottir, A. & Nørskov, J. K. Electrolysis of water on (oxidized) metal surfaces. Chem. Phys. 319, 178–184 (2005).
137. Nørskov, J. K., Abild-Pedersen, F., Studt, F. & Bligaard, T. Density functional theory in surface chemistry and catalysis. Proc. Natl. Acad. Sci. 108, 937–943 (2011).
138. Feng, Z. et al. Theoretical computation of the electrocatalytic performance of CO2 reduction and hydrogen evolution reactions on graphdiyne monolayer supported precise number of copper atoms. Int. J. Hydrog. Energy 46, 5378–5389 (2021).
139. Wang, M. et al. Theoretical Expectation and Experimental Implementation of In Situ Al-Doped CoS2 Nanowires on Dealloying-Derived Nanoporous Intermetallic Substrate as an Efficient Electrocatalyst for Boosting Hydrogen Production. ACS Catal. 9, 1489–1502 (2019).
140. Quaino, P., Juarez, F., Santos, E. & Schmickler, W. Volcano plots in hydrogen electrocatalysis – uses and abuses. Beilstein J. Nanotechnol. 5, 846–854 (2014).
141. Qi, K. et al. Decoration of the inert basal plane of defect-rich MoS 2 with Pd atoms for achieving Pt-similar HER activity. J. Mater. Chem. A 4, 4025–4031 (2016).
142. Valenti, G. et al. Co-axial heterostructures integrating palladium/titanium dioxide with carbon nanotubes for efficient electrocatalytic hydrogen evolution. Nat. Commun. 7, 13549 (2016).
143. Bakhmutsky, K. et al. A Versatile Route to Core–Shell Catalysts: Synthesis of Dispersible M@Oxide (M=Pd, Pt; Oxide=TiO2, ZrO2) Nanostructures by Self-Assembly. ChemSusChem 5, 140–148 (2012).
144. Ibupoto, Z. H. et al. MoSx@NiO Composite Nanostructures: An Advanced Nonprecious Catalyst for Hydrogen Evolution Reaction in Alkaline Media. Adv. Funct. Mater. 29, 1807562 (2019).
145. Carrasco, J. et al. In Situ and Theoretical Studies for the Dissociation of Water on an Active Ni/CeO2 Catalyst: Importance of Strong Metal–Support Interactions for the Cleavage of O–H Bonds. Angew. Chem. Int. Ed. 54, 3917–3921 (2015).
146. Bhalothia, D., Chen, P.-C., Yan, C., Wang, K.-W. & Chen, T.-Y. Heterogeneous NiO2-to-Pd Epitaxial Structure Performs Outstanding Oxygen Reduction Reaction Activity. J. Phys. Chem. C 124, 2295–2306 (2020).
147. Bhalothia, D. et al. A highly mismatched NiO2-to-Pd hetero-structure as an efficient nanocatalyst for the hydrogen evolution reaction. Sustain. Energy Fuels 4, 2541–2550 (2020).
148. Greeley, J., Jaramillo, T. F., Bonde, J., Chorkendorff, I. & Nørskov, J. K. Computational high-throughput screening of electrocatalytic materials for hydrogen evolution. Nat. Mater. 5, 909–913 (2006).
149. Liao, T., Kou, L., Du, A., Gu, Y. & Sun, Z. Simplest MOF Units for Effective Photodriven Hydrogen Evolution Reaction. J. Am. Chem. Soc. 140, 9159–9166 (2018).
150. Yan, C. et al. Local synergetic collaboration between Pd and local tetrahedral symmetric Ni oxide enables ultra-high-performance CO2 thermal methanation. J. Mater. Chem. A 8, 12744–12756 (2020).
151. Rankin, R. B. & Waldt, C. T. Computational Screening for Developing Optimal Intermetallic Transition Metal Pt-Based ORR Catalysts at the Predictive Volcano Peak. J. Phys. Chem. C 123, 13236–13245 (2019).
152. Liu, J. et al. NiO as a Bifunctional Promoter for RuO2 toward Superior Overall Water Splitting. Small 14, 1704073 (2018).
153. Bhalothia, D. et al. Sub-nanometer Pt cluster decoration enhances the oxygen reduction reaction performances of NiO x supported Pd nano-islands. Sustain. Energy Fuels 4, 809–823 (2020).
154. Hammer, B. & Nørskov, J. K. Theoretical Surface Science and Catalysis — Calculations and Concepts. Adv. Catal. 45, 71–129 (2000).
155. Stacy, J., Regmi, Y. N., Leonard, B. & Fan, M. The recent progress and future of oxygen reduction reaction catalysis: A review. Renew. Sustain. Energy Rev. 69, 401–414 (2017).
156. Huang, L. et al. Advanced Platinum-Based Oxygen Reduction Electrocatalysts for Fuel Cells. Acc. Chem. Res. 54, 311–322 (2021).
157. Lefèvre, M., Proietti, E., Jaouen, F. & Dodelet, J.-P. Iron-Based Catalysts with Improved Oxygen Reduction Activity in Polymer Electrolyte Fuel Cells. Science 324, 71–74 (2009).
158. Gewirth, A. A., Varnell, J. A. & DiAscro, A. M. Nonprecious Metal Catalysts for Oxygen Reduction in Heterogeneous Aqueous Systems. Chem. Rev. 118, 2313–2339 (2018).
159. Yi, S. et al. Recent progress of Pt-based catalysts for oxygen reduction reaction in preparation strategies and catalytic mechanism. J. Electroanal. Chem. 848, 113279 (2019).
160. Yuan, Y. et al. Zirconium nitride catalysts surpass platinum for oxygen reduction. Nat. Mater. 19, 282–286 (2020).
161. Trens, P. et al. Poisoning of Pt/C catalysts by CO and its consequences over the kinetics of hydrogen chemisorption. Appl. Catal. B Environ. 92, 280–284 (2009).
162. Vogel, W., Lundquist, L., Ross, P. & Stonehart, P. Reaction pathways and poisons—II: The rate controlling step for electrochemical oxidation of hydrogen on Pt in acid and poisoning of the reaction by CO. Electrochimica Acta 20, 79–93 (1975).
163. Lai, J. & Guo, S. Design of Ultrathin Pt-Based Multimetallic Nanostructures for Efficient Oxygen Reduction Electrocatalysis. Small 13, 1702156 (2017).
164. Zhang, J., Yang, H., Fang, J. & Zou, S. Synthesis and Oxygen Reduction Activity of Shape-Controlled Pt3Ni Nanopolyhedra. Nano Lett. 10, 638–644 (2010).
165. Bhalothia, D., Lin, C.-Y., Yan, C., Yang, Y.-T. & Chen, T.-Y. Effects of Pt metal loading on the atomic restructure and oxygen reduction reaction performance of Pt-cluster decorated Cu@Pd electrocatalysts. Sustain. Energy Fuels 3, 1668–1681 (2019).
166. Sharma, S., Zeng, C. & Peterson, A. A. Face-centered tetragonal (FCT) Fe and Co alloys of Pt as catalysts for the oxygen reduction reaction (ORR): A DFT study. J. Chem. Phys. 150, 041704 (2018).
167. Yılmaz, M. S., Kaplan, B. Y., Gürsel, S. A. & Metin, Ö. Binary CuPt alloy nanoparticles assembled on reduced graphene oxide-carbon black hybrid as efficient and cost-effective electrocatalyst for PEMFC. Int. J. Hydrog. Energy 44, 14184–14192 (2019).
168. Liu, Q. et al. Structurally Ordered Fe3Pt Nanoparticles on Robust Nitride Support as a High Performance Catalyst for the Oxygen Reduction Reaction. Adv. Energy Mater. 9, 1803040 (2019).
169. Liu, T., Li, C. & Yuan, Q. Facile Synthesis of PtCu Alloy/Graphene Oxide Hybrids as Improved Electrocatalysts for Alkaline Fuel Cells. ACS Omega 3, 8724–8732 (2018).
170. Kaito, T. et al. In Situ X-ray Absorption Fine Structure Analysis of PtCo, PtCu, and PtNi Alloy Electrocatalysts: The Correlation of Enhanced Oxygen Reduction Reaction Activity and Structure. J. Phys. Chem. C 120, 11519–11527 (2016).
171. Zhao, Q. et al. H2-induced thermal treatment significantly influences the development of a high performance low-platinum core-shell PtNi/C alloyed oxygen reduction catalyst. Int. J. Energy Res. 44, 4773–4783 (2020).
172. Leteba, G. M. et al. High-Index Core–Shell Ni–Pt Nanoparticles as Oxygen Reduction Electrocatalysts. ACS Appl. Nano Mater. 3, 5718–5731 (2020).
173. Strickler, A. L., Jackson, A. & Jaramillo, T. F. Active and Stable Ir@Pt Core–Shell Catalysts for Electrochemical Oxygen Reduction. ACS Energy Lett. 2, 244–249 (2017).
174. Yang, H. Platinum-Based Electrocatalysts with Core–Shell Nanostructures. Angew. Chem. Int. Ed. 50, 2674–2676 (2011).
175. Nair, A. S. & Pathak, B. Computational Screening for ORR Activity of 3d Transition Metal Based M@Pt Core–Shell Clusters. J. Phys. Chem. C 123, 3634–3644 (2019).
176. Yoo, T. Y. et al. Direct Synthesis of Intermetallic Platinum–Alloy Nanoparticles Highly Loaded on Carbon Supports for Efficient Electrocatalysis. J. Am. Chem. Soc. 142, 14190–14200 (2020).
177. Cao, S., Tao, F. (Feng), Tang, Y., Li, Y. & Yu, J. Size- and shape-dependent catalytic performances of oxidation and reduction reactions on nanocatalysts. Chem. Soc. Rev. 45, 4747–4765 (2016).
178. Yano, H. et al. Particle-size effect of nanoscale platinum catalysts in oxygen reduction reaction: an electrochemical and 195Pt EC-NMR study. Phys. Chem. Chem. Phys. 8, 4932–4939 (1385).
179. Nesselberger, M. et al. The Particle Size Effect on the Oxygen Reduction Reaction Activity of Pt Catalysts: Influence of Electrolyte and Relation to Single Crystal Models. J. Am. Chem. Soc. 133, 17428–17433 (2011).
180. Wang, W. et al. Shape inducer-free polygonal angle platinum nanoparticles in graphene oxide as oxygen reduction catalyst derived from gamma irradiation. J. Colloid Interface Sci. 575, 1–15 (2020).
181. Sandbeck, D. J. S. et al. Particle Size Effect on Platinum Dissolution: Considerations for Accelerated Stability Testing of Fuel Cell Catalysts. ACS Catal. 10, 6281–6290 (2020).
182. Fruehwald, H. M., Ebralidze, I. I., Melino, P. D., Zenkina, O. V. & Easton, E. B. Probing the Influence of the Carbon Support on the Activity of Fe-N3/C Model Active Sites for the Oxygen Reduction Reaction. J. Electrochem. Soc. 167, 084520 (2020).
183. Xiong, Y. et al. Pt-Decorated, Nanocarbon-Intercalated, and N-Doped Graphene with Enhanced Activity and Stability for Oxygen Reduction Reaction. ACS Appl. Energy Mater. 3, 2490–2495 (2020).
184. Uchida, M. PEFC catalyst layers: Effect of support microstructure on both distributions of Pt and ionomer and cell performance and durability. Curr. Opin. Electrochem. 21, 209–218 (2020).
185. Zhong, L. & Li, S. Unconventional Oxygen Reduction Reaction Mechanism and Scaling Relation on Single-Atom Catalysts. ACS Catal. 10, 4313–4318 (2020).
186. Zhang, J. et al. Tuning the Coordination Environment in Single-Atom Catalysts to Achieve Highly Efficient Oxygen Reduction Reactions. J. Am. Chem. Soc. 141, 20118–20126 (2019).
187. Xiao, M. et al. A Single-Atom Iridium Heterogeneous Catalyst in Oxygen Reduction Reaction. Angew. Chem. 131, 9742–9747 (2019).
188. Kan, D. et al. Screening effective single-atom ORR and OER electrocatalysts from Pt decorated MXenes by first-principles calculations. J. Mater. Chem. A 8, 17065–17077 (2020).
189. Peng, L., Shang, L., Zhang, T. & Waterhouse, G. I. N. Recent Advances in the Development of Single-Atom Catalysts for Oxygen Electrocatalysis and Zinc–Air Batteries. Adv. Energy Mater. 10, 2003018 (2020).
190. Bhalothia, D. et al. Programming ORR Activity of Ni/NiOx@Pd Electrocatalysts via Controlling Depth of Surface-Decorated Atomic Pt Clusters. ACS Omega 3, 8733–8744 (2018).
191. Dai, S. et al. Platinum-trimer decorated cobalt-palladium core-shell nanocatalyst with promising performance for oxygen reduction reaction. Nat. Commun. 10, 440 (2019).
192. Bhalothia, D. et al. Conformational Effects of Pt-Shells on Nanostructures and Corresponding Oxygen Reduction Reaction Activity of Au-Cluster-Decorated NiOx@Pt Nanocatalysts. Nanomaterials 9, 1003 (2019).
193. Bhalothia, D. et al. Ir-oxide mediated surface restructure and corresponding impacts on durability of bimetallic NiOx@Pd nanocatalysts in oxygen reduction reaction. J. Alloys Compd. 844, 156160 (2020).
194. Wang, C.-H., Hsu, H.-C. & Wang, K.-C. Iridium-decorated Palladium–Platinum core–shell catalysts for oxygen reduction reaction in proton exchange membrane fuel cell. J. Colloid Interface Sci. 427, 91–97 (2014).
195. Luo, L.-M. et al. Ternary CoAuPd and binary AuPd electrocatalysts for methanol oxidation and oxygen reduction reaction: Enhanced catalytic performance by surface reconstruction. J. Power Sources 412, 142–152 (2019).
196. Feng, Y. et al. Surface-modulated palladium-nickel icosahedra as high-performance non-platinum oxygen reduction electrocatalysts. Sci. Adv. 4, eaap8817 (2018).
197. Jiang, J. et al. Ni–Pd core–shell nanoparticles with Pt-like oxygen reduction electrocatalytic performance in both acidic and alkaline electrolytes. J. Mater. Chem. A 5, 9233–9240 (2017).
198. Wu, Y., Wang, C., Zou, L., Huang, Q. & Yang, H. Incorporation of cobalt into Pd2Sn intermetallic nanoparticles as durable oxygen reduction electrocatalyst. J. Electroanal. Chem. 789, 167–173 (2017).
199. Cui, Z., Chen, H., Zhao, M. & DiSalvo, F. J. High-Performance Pd3Pb Intermetallic Catalyst for Electrochemical Oxygen Reduction. Nano Lett. 16, 2560–2566 (2016).
200. Holade, Y. et al. Facile synthesis of highly active and durable PdM/C (M = Fe, Mn) nanocatalysts for the oxygen reduction reaction in an alkaline medium. J. Mater. Chem. A 4, 8337–8349 (2016).
201. Kuttiyiel, K. A. et al. Gold-promoted structurally ordered intermetallic palladium cobalt nanoparticles for the oxygen reduction reaction. Nat. Commun. 5, 5185 (2014).
202. Lu, Y., Jiang, Y., Gao, X., Wang, X. & Chen, W. Strongly Coupled Pd Nanotetrahedron/Tungsten Oxide Nanosheet Hybrids with Enhanced Catalytic Activity and Stability as Oxygen Reduction Electrocatalysts. J. Am. Chem. Soc. 136, 11687–11697 (2014).