Progress and perspective of single‐atom catalysts for membrane electrode assembly of fuel cells

Abstract A fuel cell is an energy conversion device that can continuously input fuel and oxidant into the device through an electrochemical reaction to release electrical energy. Although noble metals show good activity in fuel cell‐related electrochemical reactions, their ever‐increasing price considerably hinders their industrial application. Improvement of atom utilization efficiency is considered one of the most effective strategies to improve the mass activity of catalysts, and this allows for the use of fewer catalysts, saving greatly on the cost. Thus, single‐atom catalysts (SACs) with an atom utilization efficiency of 100% have been widely developed, which show remarkable performance in fuel cells. In this review, we will describe recent progress on the development of SACs for membrane electrode assembly of fuel cell applications. First, we will introduce several effective routes for the synthesis of SACs. The reaction mechanism of the involved reactions will also be introduced as it is highly determinant of the final activity. Then, we will systematically summarize the application of Pt group metal (PGM) and nonprecious group metal (non‐PGM) catalysts in membrane electrode assembly of fuel cells. This review will offer numerous experiences for developing potential industrialized fuel cell catalysts in the future.