Advanced Trifunctional Electrocatalysis with Cu-, N-, S-Doped Defect-Rich Porous Carbon for Rechargeable Zn-Air Batteries and Self-Driven Water Splitting

Fuel cells and water splitting are promising sustainable energy storage and conversion systems that can facilitate the usage of renewable resources and reduce the reliance on fossil fuels. These applications require catalysts to perform the required oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). It would be ideal to use a non-noble metal-based multifunctional catalyst for these reactions. Herein, a new type of porous carbon doped with Cu, N, S was prepared as a trifunctional catalyst for the ORR, OER, and HER from S-rich polyphenylene sulfide (PPS). By oxidatively treating the PPS, we critically prevented high-temperature melting of the precursor. Further, high-temperature pyrolysis using ammonia (NH3) desulfurized and introduced N into the carbon matrix, increasing structural defects and the surface area. By introducing copper during the pyrolysis, the tridoped (Cu, N, S) catalyst was successfully synthesized. The extremely large number of active sites and the local chemical environment enable excellent electrocatalytic performance and stability across ORR, OER, and HER at levels superior or comparable to noble metals. This catalyst was also used as the sole catalyst in Zn-air batteries and overall water splitting to demonstrate excellent performance. This synthesis method can pave the way toward new catalyst design and discovery, enabling more versatile and robust energy applications.