Modification of the ultrasonication derived-g-C3N4 nanosheets/quantum dots by MoS2 nanostructures to improve electrocatalytic hydrogen evolution reaction

Abstract

In this work, graphitic carbon nitride (g-C3N4) nanosheets/quantum dots (NS/QD) was prepared using a simple and low-cost procedure. By two steps exfoliation in a bath and tip sonicator, the g-C3N4 (NS/QD) was produced from bulk g-C3N4. To improve electrocatalytic hydrogen evolution reaction (HER), the g-C3N4 (NS/QD) were modified by the MoS2 nanostructures. Nanocomposite of the g-C3N4 (NS/QD) with MoS2 nanostructures was deposited on a flexible, conductive and three dimensional carbon cloth by a facile and binder-free electrophoretic technique. This electrode exhibited a Tafel slope of 88 mV/dec and an overpotential of 0.28 V vs RHE at −2 mA/cm2, lower than that of the g-C3N4, and good stability after 1000 cycles and 100 days for HER. The enhanced electrocatalytic performance was attributed to the MoS2 and g-C3N4 nanostructures on three dimensional carbon cloth, leading to high surface area and more number of the exposed active sites for HER. This heterostructure improved charge transport, proton adsorption and hydrogen evolution on the electrode. This work proposes cost-effective, stable and three dimensional g-C3N4 based electrode for hydrogen evolution reaction.