Construction of a Mo_xC/Ni network electrode with low overpotential for hydrogen generation

The integration of commercial photovoltaic devices and electrocatalysts has attracted considerable interest to realize the conversion of solar power to renewable hydrogen energy. However, a noble metal electrocatalyst (Pt) is too expensive and rare, which inspires the development of efficient and economical catalytic electrodes. Herein, we have fabricated a 3D Mo_xC/Ni network through the carbonization of a polyaniline-Mo₇O₂₄ precursor, which was electrochemically deposited on Ni foam in advance. If the 3D Mo_xC/Ni network is used as a catalytic electrode for the hydrogen evolution reaction (HER), a low onset potential of approximately 44 mV for driving 1 mAcm^-2 of current density and a Tafel slope of approximately 49 mVdecade^-1 (overpotential η=50-60 mV) are obtained. Moreover, the apparent exchange current density reaches approximately 0.1 mAcm^-2. After a long-term HER test at η=100 mV or 500 CV sweeps, no deactivation is observed. This excellent electrocatalytic performance of the 3D Mo_xC/Ni network promotes it as a promising earth-abundant HER electrode.