Photo/electrocatalytic hydrogen evolution using Type-II Cu₂O/g-C₃N₄ Heterostructure: Density functional theory...

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 Cu₂O/g-C₃N₄ 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-C₃N₄. In addition, Cu₂O/g-C₃N₄ 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-C₃N₄ (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 Cu₂O to the n-type g-C₃N₄ using density functional theory (DFT) calculations.