Photo/electrocatalytic hydrogen evolution using Type-II Cu2O/g-C3N4 Heterostructure: Density functional theory addresses the improved charge transport efficiency
Amir Mehtab, Yuanbing Mao, Saad M. Alshehri, Tokeer Ahmad
Abstract
One of the most efficient ways for the photogenerated charge carriers is by the development of heterojunction between p-type and n -type semiconductors, which creates an interfacial charge transfer between two semiconductors. By enhancing the bifunctional characteristics for hydrogen generation via photocatalytic and electrocatalytic water splitting reaction, we report the type-II Cu 2 O/g-C 3 N 4 heterostructure in this article. Due to significantly increased catalytically active sites for the hydrogen evolution reaction (HER) reaction during electrocatalysis and decreased charge transfer resistance, the as-prepared heterostructure exhibits a lower overpotential of 47 and 72 mVdec -1 for the HER and oxygen evolution reactions (OER), respectively, when compared to alone g-C 3 N 4 . In addition, Cu 2 O/g-C 3 N 4 heterostructures have a higher photocatalytic hydrogen evolution of 3492 µmol g cat - 1 in the presence of Triethanolamine as a sacrificial agent, which is nearly 2-fold times greater than g-C 3 N 4 (1818 µmol g cat - 1 ) after 5 h of continuous light-irradiation. Moreover, produced heterostructure exhibits 81% of Faradaic efficiency and 18% of apparent quantum yield. This work successfully explains how the rise in water splitting is induced by the transfer of photogenerated electrons in a cascade way from p-type Cu 2 O to the n -type g-C 3 N 4 using density functional theory (DFT) calculations.