Electron density modulation of NiCo2S4 nanowires by nitrogen incorporation for highly efficient hydrogen evolution catalysis

Yishang Wu,Jinyan Cai,Xusheng Zheng,Yufang Xie,Shaoyang Wu,Xianyin Song,Dongdong Han,Xiaojing Liu,Shuwen Niu,Xiangheng Xiao,Zhiyan Chen,Gongming Wang,Yao Song,Lei Shi,Jian Kang,Jianbin Zhou

doi:10.1038/s41467-018-03858-w

Abstract

Metal sulfides for hydrogen evolution catalysis typically suffer from unfavorable hydrogen desorption properties due to the strong interaction between the adsorbed H and the intensely electronegative sulfur. Here, we demonstrate a general strategy to improve the hydrogen evolution catalysis of metal sulfides by modulating the surface electron densities. The N modulated NiCo2S4 nanowire arrays exhibit an overpotential of 41 mV at 10 mA cm−2 and a Tafel slope of 37 mV dec−1, which are very close to the performance of the benchmark Pt/C in alkaline condition. X-ray photoelectron spectroscopy, synchrotron-based X-ray absorption spectroscopy, and density functional theory studies consistently confirm the surface electron densities of NiCo2S4 have been effectively manipulated by N doping. The capability to modulate the electron densities of the catalytic sites could provide valuable insights for the rational design of highly efficient catalysts for hydrogen evolution and beyond.

Highlights

Metal sulfides for hydrogen evolution catalysis typically suffer from unfavorable hydrogen desorption properties due to the strong interaction between the adsorbed H and the intensely electronegative sulfur
Ni-Co-carbonate hydroxides (Ni–Co–O) nanowire arrays (NWs) were directly grown on the Ni foam through a well-developed hydrothermal synthesis, with Co(NO3)[2] and Ni(NO3)[2] as the metal sources and urea as the pH regulator
SHte2p+cOouHld−)beinthaelkHaleinyreocvosknydiptiroonc,eswsh(iHch2Om+eaMns-Hth*e rate-determining hydrogen evolution reaction (HER) process of N-NiCo2S4 is closely related to water dissociation and H* desorption[38,39]. Considering defects such as partial oxidization or sulfur defects may be introduced during material preparation, we systematically study the effects of these defects on the HER catalysis and evaluate their contributions to the total performance

Summary

Introduction

Metal sulfides for hydrogen evolution catalysis typically suffer from unfavorable hydrogen desorption properties due to the strong interaction between the adsorbed H and the intensely electronegative sulfur. We demonstrate a general strategy to improve the hydrogen evolution catalysis of metal sulfides by modulating the surface electron densities. The capability to modulate the electron densities of the catalytic sites could provide valuable insights for the rational design of highly efficient catalysts for hydrogen evolution and beyond. We demonstrate a facile and general strategy to modulate the electron densities of the catalytic sites of NiCo2S4 nanowire arrays (NWs) for high performance HER activity by using nitrogen as the modulator.

Methods

Results

Conclusion