Facilitated Water Adsorption and Dissociation on Ni/Ni3S2 Nanoparticles Embedded in Porous S-doped Carbon Nanosheet Arrays for Enhanced Hydrogen Evolution

Three-dimensional carbon-based catalysts grown on a conductive substrate offer superior electrocatalytic activities toward hydrogen evolution reaction (HER). Herein, a novel method is described for in situ fabrication of hybrid Ni/Ni3S2 nanoparticles embedded in S-doped carbon nanosheet arrays (Ni/Ni3S2/SC NSAs) on carbon cloth. With the morphological merits of large surface area and high conductivity, Ni/Ni3S2/SC NSAs are demonstrated as an efficient and durable HER catalyst that requires merely 90 mV at a current density of 10 mA cm(-2) with a small Tafel slope of 81 mV dec(-1). This excellent performance is ascribed to the excellent H2O adsorption property of S-doped C layer and formation of Ni delta+ and S delta- species that promote the cleavage of H-OH bonds. First-principles calculations further reveal that the Ni surface near the Ni/Ni3S2 interface has a larger water adsorption energy (E-ad) and lower activation energy for water dissociation (E-a) than pure Ni and Ni3S2, which contribute to enhanced HER performance. This work offers valuable insights into the designing of interface between transition metal-based catalysts and heteroatom-doped carbon materials.

Automated summary

A novel method for in situ fabrication of Ni/Ni3S2/SC NSAs catalyst on carbon cloth is introduced, showing superior electrocatalytic activities towards hydrogen evolution reaction (HER). The catalyst has excellent performance with large surface area and high conductivity, promoting H-OH bond cleavage and forming species that enhance the HER performance.