Enhancement of hydrogen desorption for electrocatalytic hydrogen evolution on nickel-coupled graphite carbon nitride catalysts

Due to low activation energy, fast kinetics, and high efficiency, electrocatalysis plays a vital role in hydrogen evolution. Graphite carbon nitrogen (g-C3N4), a new type of organic conjugated semiconductor, has an adjustable electronic structure and excellent chemical stability, but its sluggish electron transfer kinetics and low intrinsic activity severely limit the electrocatalytic hydrogen production. Herein, based on our previous nickel-based electrode work, we exploit the conjugation of rGO to enhance the in-plane electron mobility of g-C3N4 and deposit nickel onto triazine units to promote water dissociation by virtue of the coupling effect. The optimized rGO/g-C3N4/Ni electrode exhibits excellent hydrogen evolution reaction (HER) performance with lower negative overpotentials of 74 mV and 109 mV at 60 and 100 mA cm(-2) and good stability under alkaline conditions. Density functional theory (DFT) calculations indicate that nickel-coupled g-C3N4 active sites present superior interfacial activity in the adsorption/desorption of H*. This work provides a feasible way for the coordination of g-C3N4 in boosting electrocatalytic hydrogen evolution.