The cactus bulb-shaped metal-S-C/N nanoparticles supported by highly conductive channels for efficient electrocatalytic hydrogen evolution reaction

Accelerating electron transfer and exposing active sites are key factors that could improve electrocatalytic hydrogen evolution reaction (HER). In this study, Co3S4-Ni3S2-C/N, the cactus bulb-shaped nanoparticles based on metal-organic frameworks (MOFs), were suc-cessfully prepared. The catalyst requires only 101 and 227 mV overpotential to reach current densities of 20 and 100 mA cm-2, respectively, in 1 M KOH. The high catalytic activity is attributed to the confinement effect achieved by introducing 2-aminoterephthalic acid as a precursor, allowing the catalyst to have a small particle size and fully exposed metal active sites. Moreover, the catalyst has a highly conductive metal -S-C/N channel that effectively reduces the intrinsic charge transfer resistance of the cat-alytic electrode, improves its conductivity, and modulates the electron density at the metal active site. Furthermore, compared to other crystal planes, the exposed (111) crystal plane of Co3S4 provides the most octahedral coordination of high spin state Co3+, which is highly catalytically active. This makes it the dominant crystal plane for catalysis. Through spatial confinement effect to limit metal sulfide particle size and introducing an organic backbone to create highly conductive metal-S-C/N channels, our study provides a general approach to developing highly active catalytic materials.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.