An amorphous FeMoS₄ nanorod array toward efficient hydrogen evolution electrocatalysis under neutral conditions

It is highly attractive to develop efficient hydrogen-evolving electrocatalysts under neutral conditions. In this communication, we report an amorphous FeMoS₄ nanorod array on carbon cloth (FeMoS₄ NRA/CC) prepared by hydrothermal treatment of an FeOOH nanorod array on carbon cloth (FeOOH NRA/CC) in (NH₄)₂MoS₄ solution. As a 3D electrode for hydrogen evolution electrocatalysis, this FeMoS₄ NRA/CC demonstrates superior catalytic activity and strong long-term electrochemical durability in 1.0 M phosphate buffered saline (pH: 7). It needs an overpotential of 204 mV to drive a geometrical current density of 10 mA cm^-2, which is 450 mV less than that for FeOOH NRA/CC. Density functional theory calculations suggest that FeMoS₄ has a more favourable hydrogen adsorption free energy than FeOOH.