Recent progress in pyrolyzed carbon materials as electrocatalysts for the oxygen reduction reaction

The oxygen reduction reaction (ORR) is an important reaction in fuel cells. The efficiency of the ORR is related to the efficiency of fuel cells. Therefore, research on ORR catalysts is an essential issue. Non-precious metal catalysts (NPMCs) have been a research hotspot in recent years due to cost considerations, and carbon-based catalysts are an important component of NPMCs. Carbon-based catalysts have a wide range of sources, are low-cost, and have superior performance and good stability. In this review, the pyrolysis step in the preparation of carbon-based catalysts was utilized to analyze the composition of the pyrolysis precursor and the effect of the structure on the catalytic activity of the catalyst. We classify carbon-based catalysts into four types depending on the type of precursor: biomass-derived, organic mixture-derived, MOF-derived, and molded carbon material-derived carbon-based catalyst. At the same time, the influence of pyrolysis conditions on the catalytic activity of the product was considered.