Ni/MoC heteronanoparticles encapsulated within nitrogen-doped carbon nanotube arrays as highly efficient self-supported electrodes for overall water splitting

Abstract

Electrochemical water splitting is one of the most clean and economical method for the production of hydrogen fuels for sustainable energy sources. In order to acquire large-scale hydrogen production, low-cost and robust bifunctional catalysts are needed to catalyze hydrogen and oxygen evolution reactions (HER and OER). Herein, nitrogen-doped carbon nanotube (NCNT) arrays are successfully constructed on the carbon cloth (CC) as bifunctional catalysts for overall water splitting via a facile strategy. Structural analyses indicate that the Ni and MoC nanoparticles are encapsulated in the NCNTs. Experimental results imply that the synergistic effect between Ni and MoC, high electrical conductivity, and binder-free electrode configuration endow the self-supported electrode to have excellent activities with a current density of 10 mA cm−2, at low overpotentials of 70 and 219 mV for HER and OER, respectively. When applied as two-electrode electrolyzer, the self-supported electrodes only need a cell voltage of 1.535 V at a current density of 10 mA cm−2, superior to the benchmark Pt/C and IrO2 couple. Furthermore, the electrolyzer exhibits remarkable stability even at a current density beyond 100 mA cm−2 over 30 h. This strategy will open a facile method to the expansion of high-efficiency bifunctional electrocatalysts for commercial water splitting.