Self-generated FeSe2 and CoSe2 nanoparticles confined in N, S-doped porous carbon as efficient and stable electrocatalyst for oxygen evolution reaction

Transition metal selenides embedded into a nitrogen, sulfur co-doped carbon materials (TMS@NSC) are promising electrocatalysts to effectively address the sluggish kinetics of oxygen evolution reaction (OER). However, the OER catalytic activity of single metal TMS@NSC is still limited by insufficient active sites. Hence, FeSe 2 and CoSe 2 nanoparticles self-generated and confined in N, S-doped porous carbon (FeSe 2 /CoSe 2 @NSC) catalyst has been synthesized by in-situ polymerization and the subsequent low temperature selenization strategy, aiming to increase the active sites of TMS@NSC. The hybridized FeSe 2 /CoSe 2 @NSC catalyst has excellent OER catalytic activity and good durability in alkaline media, which only requiring an overpotential as low as 278 mV to drive a current density of 10 mA cm −2 , outperforming most recently reported selenide catalysts and commercial RuO 2 catalysts. The high catalytic activity of FeSe 2 /CoSe 2 @NSC catalyst is attributed to the rapid electron transfer between FeSe 2 and CoSe 2 in the unique N, S-doped graphene nanosheets, which effectively inhibits the aggregation of nanoparticles, fully exposes the active sites and provides pathway for oxygen release during the OER process. Moreover, the overall water splitting device assembled with FeSe 2 /CoSe 2 @NSC catalyst showed low overpotential of 1.57 V. This study provides a feasible strategy for the design of high active and stable TMS@NSC catalysts for OER and other energy conversion applications.