A reversible fuel cell (RFC), which integrates a fuel cell with an electrolyzer, is similar to a rechargeable battery. This technology lies on high-performance bifunctional catalysts for the oxygen reduction reaction (ORR) in the fuel cell mode and the oxygen evolution reaction (OER) in the electrolyzer mode. Current catalysts are platinum group metals (PGM) such as Pt and Ir, which are expensive and scarce. Therefore, it is highly desirable to develop PGM-free catalysts for large-scale application of RFCs. In this mini review, we discussed the most promising nanocarbon/oxide composite catalysts for ORR/OER bifunctional catalysis in alkaline media, which is mainly based on our recent progress. Starting with the effectiveness of selected oxides and nanocarbons in terms of their activity and stability, we outlined synthetic methods and the resulting structures and morphologies of catalysts to provide a correlation between synthesis, structure, and property. A special emphasis is put on understanding of the possible synergistic effect between oxide and nanocarbon for enhanced performance. Finally, a few nanocomposite catalysts are discussed as typical examples to elucidate the rules of designing highly active and durable bifunctional catalysts for RFC applications.

将燃料电池与电解槽集成在一起的可逆燃料电池（RFC）与可充电电池相似。该技术基于高性能双功能催化剂，用于燃料电池模式下的氧气还原反应（ORR）和电解槽模式下的氧气析出反应（OER）。当前的催化剂是铂族金属（PGM），例如Pt和Ir，它们昂贵且稀缺。因此，非常需要开发用于RFC的大规模应用的无PGM的催化剂。在这个小型综述中，我们讨论了在碱性介质中用于ORR / OER双功能催化的最有前途的纳米碳/氧化物复合催化剂，这主要是基于我们最近的进展。从所选氧化物和纳米碳的活性和稳定性方面的有效性开始，我们概述了合成方法以及所得到的催化剂的结构和形态，以提供合成，结构和性能之间的关联。特别强调理解氧化物和纳米碳之间可能产生的协同效应，以提高性能。最后，讨论了一些纳米复合催化剂作为典型实例，以阐明为RFC应用设计高活性和耐用性的双功能催化剂的规则。