Advanced Atomically Dispersed Metal–Nitrogen–Carbon Catalysts Toward Cathodic Oxygen Reduction in PEM Fuel Cells

Abstract

Proton exchange membrane fuel cells (PEMFCs) are a highly efficient hydrogen energy conversion technology, which shows great potential in mitigating carbon emissions and the energy crisis. Currently, to accelerate the kinetics of the oxygen reduction reaction (ORR) required for PEMFCs, extensive utilization of expensive and rare platinum‐based catalysts are required at the cathodic side, impeding their large‐scale commercialization. In response to this issue, atomically dispersed metal–nitrogen–carbon (M–N–C) catalysts with cost‐effectiveness, encouraging activity, and unique advantages (e.g., homogeneous activity sites, high atom efficiency, and intrinsic activity) have been widely investigated. Considerable progress in this domain has been witnessed in the past decade. Herein, a comprehensive summary of recent development in atomically dispersed M–N–C catalysts for the ORR under acidic conditions and of their application in the membrane electrode assembly (MEA) of PEM fuel cells, are presented. The ORR mechanisms, composition, and operating principles of PEMFCs are introduced. Thereafter, atomically dispersed M–N–C catalysts towards improved acidic ORR and MEA performance is summarized in detail, and improvement strategies for MEA performance and stability are systematically analyzed. Finally, remaining challenges and significant research directions for design and development of high‐performance atomically dispersed M–N–C catalysts and MEA are discussed.

Non‐Covalent Interaction of Atomically Dispersed Cu and Zn Pair Sites for Efficient Oxygen Reduction Reaction

“…[1] Efficient and affordable electrocatalysts are momentous to remedy this shortcoming of zinc-air batteries. [2] discussion on the synergistic interaction between metal atoms in dual-atomic catalysts. Recently, dual-atom Fe and Ni catalyst with long-range electronic interactions between metallic Fe and Ni atoms was reported to facilitate the electrocatalytic reduction of CO 2 and corresponding Faraday efficiency by activating the adjacent metal Fe site via the Ni site.…”

Research progress of asymmetrically coordinated single-atom catalysts for electrocatalytic reactions

“…1 Single atom catalysts (SACs) have the advantages of unique electronic and geometric structures, nearly 100% atomic utilization, ideal catalytic activity, and excellent product selectivity and stability. 2–5 Therefore, it has been rapidly developed in many fields such as electrocatalysis, 6 photocatalysis, 7 and enzyme catalysis. 8 At present, researchers are focusing on regulating various conditions of SACs to enhance their intrinsic activity and persistence, such as carriers, heteroatoms, coordination numbers, etc.…”

Facile fabrication of single-atom catalysts by a plasma-etching strategy for oxygen reduction reaction

“…The oxygen reduction reaction (ORR) is the heart of many new energy conversion technologies, such as hydrogen-air fuel cells and zinc-air batteries (ZABs). [21][22][23][24][25][26][27][28] As an illustration, the ORR performance of the prepared Cu-SAC/NC was investigated, and the resulting catalyst achieved an excellent ORR performance. Furthermore, superb battery performance was delivered by Cu-SAC/nanocarbon (NC) when it was used as the air-cathode catalyst for assembled ZABs, delivering a peak power density of 175 mW cm À2 and long-term stability over a period of 55 h.…”