Well-dispersed NiCoS2 nanoparticles/rGO composite with a large specific surface area as an oxygen evolution reaction electrocatalyst

Developing efficient oxygen evolution reaction (OER) electrocatalysts such as transition metal sulfides (TMSs) is of great importance to advance renewable hydrogen fuel toward further practical applications. Herein, NiCoS2 nanoparticles well decorated on double-sided N-doped reduced graphene oxide sheets (NiCoS2/rGO) are prepared from an Al-containing ternary NiCoAl-layered double hydroxide precursor (NiCoAl-LDH) grown on GO support as an OER electrocatalyst. The Al-confinement-assisted sulfurization, followed by selective acid treatment, endows the resulting NiCoS2/rGO composite with the advantages: well-dispersed NiCoS2 nanoparticles, dual-sided rGO support, as well as a large specific surface area of 119.4 m(2)center dot g(-1) and meso-/macroporous size distribution. The NiCoS2/rGO electrocatalyst exhibits an overpotential of 273 mV at 10 mA center dot cm(-2) and a good stability of 24 h, which outperform those of the counterparts of NiS2/rGO and CoS2/rGO. The results of electrochemical active surface area and electrochemical impedance spectra experimentally provide convincing rationales of the information of active sites and good conductivity, both underpin the enhanced electrocatalytic performances.

Automated summary

A NiCoS2/rGO electrocatalyst with well-dispersed nanoparticles, dual-sided graphene support, and a large specific surface area was successfully prepared. It showed superior catalytic performance in the oxygen evolution reaction, outperforming NiS2/rGO and CoS2/rGO counterparts. The enhanced electrocatalytic performances were supported by experimental results on active sites and conductivity.