Transition metal chalcogenide nanoparticles embedded metal-organic framework nanosheets for high-performance H2O2 electrosynthesis

Abstract

The rational design of high-performance two-electron oxygen reduction reaction (2e-ORR) electrocatalysts is of great significance for sustainable H2O2 production. Herein, we report the synthesis of a transition-metal chalcogenide@metal-organic framework (TMC@MOF) composite material as an efficient 2e-ORR electrocatalyst. Through a partial conversion route using NiFe-MOF nanosheets as precursors, the Ni ions are partially converted into NiS2 nanoparticles, which are embedded in the unconverted MOF skeleton with partially preserved crystalline structure and in situ generated mesopores. Experimental and theoretical results demonstrate that the interaction between NiS2 and retained MOFs regulates the electronic structure of Ni sites in NiS2 toward optimized adsorption of oxygen intermediates, enhancing the 2e-ORR selectivity. Additionally, the ultrasmall NiS2 nanoparticles (grain size < 10 nm) expose abundant active sites, and the created mesopores facilitate the mass transfer. Collectively, remarkable 2e-ORR performances are achieved with a high selectivity of 96% and a high H2O2 production rate of 4.2 mol gcat−1 h−1, superior than most reported TMCs and MOFs based electrocatalysts. This work paves the way for the design of advanced 2e-ORR electrocatalysts.