The recent advances in electrocatalysis for oxygen reduction reaction (ORR) for proton exchange membrane fuel cells (PEMFCs) are thoroughly reviewed. This comprehensive Review focuses on the low- and non-platinum electrocatalysts including advanced platinum alloys, core–shell structures, palladium-based catalysts, metal oxides and chalcogenides, carbon-based non-noble metal catalysts, and metal-free catalysts. The recent development of ORR electrocatalysts with novel structures and compositions is highlighted. The understandings of the correlation between the activity and the shape, size, composition, and synthesis method are summarized. For the carbon-based materials, their performance and stability in fuel cells and comparisons with those of platinum are documented. The research directions as well as perspectives on the further development of more active and less expensive electrocatalysts are provided.

http://repository.ust.hk/ir/bitstream/1783.1-77094/1/acs.chemrev.5b00462_withlink.pdf

Recent Advances in Electrocatalysts for Oxygen Reduction Reaction

The development of low-cost, efficient, and stable electrocatalysts for the oxygen reduction reaction (ORR) is desirable but remains a great challenge. Herein, we made a highly reactive and stable isolated single-atom Fe/N-doped porous carbon (ISA Fe/CN) catalyst with Fe loading up to 2.16 wt %. The catalyst showed excellent ORR performance with a half-wave potential (E1/2) of 0.900 V, which outperformed commercial Pt/C and most non-precious-metal catalysts reported to date. Besides exceptionally high kinetic current density (Jk) of 37.83 mV cm−2 at 0.85 V, it also had a good methanol tolerance and outstanding stability. Experiments demonstrated that maintaining the Fe as isolated atoms and incorporating nitrogen was essential to deliver the high performance. First principle calculations further attributed the high reactivity to the high efficiency of the single Fe atoms in transporting electrons to the adsorbed OH species.

Isolated Single Iron Atoms Anchored on N-Doped Porous Carbon as an Efficient Electrocatalyst for the Oxygen Reduction Reaction

Single-Atom Catalysts: Synthetic Strategies and Electrochemical Applications

Over the past few decades, the design and development of advanced electrocatalysts for efficient energy conversion technologies have been subjects of extensive study. With the discovery of graphene, two-dimensional (2D) nanomaterials have emerged as some of the most promising candidates for heterogeneous electrocatalysts due to their unique physical, chemical, and electronic properties. Here, we review 2D-nanomaterial-based electrocatalysts for selected electrocatalytic processes. We first discuss the unique advances in 2D electrocatalysts based on different compositions and functions followed by specific design principles. Following this overview, we discuss various 2D electrocatalysts for electrocatalytic processes involved in the water cycle, carbon cycle, and nitrogen cycle from their fundamental conception to their functional application. We place a significant emphasis on different engineering strategies for 2D nanomaterials and the influence these strategies have on intrinsic material performance, ...

Emerging Two-Dimensional Nanomaterials for Electrocatalysis

Achieving mastery over the synthesis of metal nanocrystals has emerged as one of the foremost scientific endeavors in recent years. This intense interest stems from the fact that the composition, size, and shape of nanocrystals not only define their overall physicochemical properties but also determine their effectiveness in technologically important applications. Our aim is to present a comprehensive review of recent research activities on bimetallic nanocrystals. We begin with a brief introduction to the architectural diversity of bimetallic nanocrystals, followed by discussion of the various synthetic techniques necessary for controlling the elemental ratio and spatial arrangement. We have selected key examples from the literature that exemplify critical concepts and place a special emphasis on mechanistic understanding. We then discuss the composition-dependent properties of bimetallic nanocrystals in terms of catalysis, optics, and magnetism and conclude the Review by highlighting applications that h...

Bimetallic Nanocrystals: Syntheses, Properties, and Applications

Reduction Reaction in Polymer Electrolyte Membrane Fuel Cells: Particle Size, Shape, and Composition Manipulation and Their Impact to Activity Yan-Jie Wang,†,‡ Nana Zhao,‡ Baizeng Fang,† Hui Li,* Xiaotao T. Bi,*,† and Haijiang Wang* †Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, BC Canada V6T 1Z3 ‡Vancouver International Clean-Tech Research Institute Inc., 4475 Wayburne Drive, Burnaby, Canada V5G 4X4 Electrochemical Materials, Energy, Mining and Environment, National Research Council Canada, 4250 Wesbrook Mall, Vancouver, BC, Canada V6T 1W5

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Carbon-Supported Pt-Based Alloy Electrocatalysts for the Oxygen Reduction Reaction in Polymer Electrolyte Membrane Fuel Cells: Particle Size, Shape, and Composition Manipulation and Their Impact to Activity

Overview of PEM Electrolysis for Hydrogen Production Nicola Briguglio and Vincenzo Antonucci Fundamentals of PEM Water Electrolysis Tom Smolinka, Emile Tabu Ojong, and Thomas Lickert Electrocatalysts for Oxygen Evolution Reaction Magnus Thomasse and Svein Sunde Electrocatalysts for the Hydrogen Evolution Reaction Marcelo Carmo, Wiebke Maier, and Detlef Stolten NSTF for PEM Water Electrolysis Krzysztof Lewinski Membrane Hiroshi Ito Bipolar Plates and Plate Materials Conghua "CH" Wang Current Collectors (GDLs) and Materials Hiroshi Ito Proton Exchange Membrane Electrolyzer Stack and System Design Julie Renner, Kathy Ayers, and Everett Anderson Characterization Tools for Polymer Electrolyte (PEM) Water Electrolyzers Pierre Millet Degradation Processes and Failure Mechanisms in PEM Water Electrolyzers Pierre Millet Modeling of PEM Water Electrolyzer Ravindra Datta, Drew J. Martino, Yan Dong, and Pyoungho Choi Fundamentals of Electrochemical Hydrogen Compression Peter Bouwman Large-Scale Water Electrolysis for Power-to-Gas Rob Harvey, Rami Abouatallah, and Joseph Cargnelli Depolarized Proton Exchange Membrane Water Electrolysis: Coupled Anodic Reactions Sergey Grigoriev, Irina Maruseva, and Artem Pushkarev Generation of Ozone and Hydrogen in a PEM Electrolyzer Dmitri Bessarabov Isotope Separation Using PEM Electrochemical Systems Mikhail Rozenkevich and Irina Rastunova

PEM Electrolysis for Hydrogen Production : Principles and Applications

A review of all‐vanadium redox flow battery durability: Degradation mechanisms and mitigation strategies

Highly dispersed 50 wt% Pt nanoparticles supported on carbon were successfully synthesized via a simple modified polyol method using different solvent volume ratios (ethylene glycol/water). The control of water proportion is found to have an important effect on the physicochemical properties of the in-house synthesized Pt/C catalysts. The structural and electrochemical characterizations reveal that the addition of water not only favors the homogeneous distribution of Pt particles with reduced particle size but also improves the electrocatalytic properties. In particular, at an optimum volume ratio of ethylene glycol to water of 45 : 23 among all studied ratios, the TEM images indicate that the as-synthesized Pt/C catalyst has a minimum particle size of 2.2 ± 0.5 nm, which is close to that of the commercial 46.6 wt% Pt/TKK catalyst, while the electrochemical measurements disclose electrochemical active surface areas and oxygen reduction reaction activity comparable to those of the commercial 46.6 wt% Pt/TKK catalyst. The simplicity of the synthesis process associated with the ease of the filtering step due to the addition of water has significant implications for its practical application in large scale production of Pt/C catalysts for polymer electrolyte membrane fuel cells.

Effect of different solvent ratio (ethylene glycol/water) on the preparation of Pt/C catalyst and its activity toward oxygen reduction reaction

In this study, we report a novel and simple synthesis strategy to fabricate a leached PtCo/C electrocatalyst, which involves no hydrogen and protective agent in the preparation process. This method is composed of a chemical impregnation, a heat treatment and a leaching procedure, producing PtCo nanoparticles of 4.7 ± 0.5 nm, slightly larger than the size of the PtCo nanoparticles prepared by a tetraoctylammonium bromide (TOAB)-assisted approach in which TOAB serves as a protective agent preventing the agglomeration of the alloy nanoparticles. After the leaching, the as-synthesized leached PtCo/C catalyst demonstrates a comparable oxygen reduction reaction mass activity to that of the TOAB-assisted leached PtCo/C catalyst, which is ca. 2-fold enhancement compared with the in-house Pt(50 wt%)/C and commercial Pt/C (TKK) catalysts.

Nana Zhao

Papers

Carbon-Supported Pt-Based Alloy Electrocatalysts for the Oxygen Reduction Reaction in Polymer Electrolyte Membrane Fuel Cells: Particle Size, Shape, and Composition Manipulation and Their Impact to Activity

PEM Electrolysis for Hydrogen Production : Principles and Applications

A review of all‐vanadium redox flow battery durability: Degradation mechanisms and mitigation strategies

Effect of different solvent ratio (ethylene glycol/water) on the preparation of Pt/C catalyst and its activity toward oxygen reduction reaction

A highly efficient PtCo/C electrocatalyst for the oxygen reduction reaction