Surface Cu+ modified ZnIn2S4 for promoted visible-light photocatalytic hydrogen evolution

Surface Cu + modified ZnIn 2 S 4 photocatalysts with spatial separation of energy levels remarkably suppress the recombination of electron and hole and thus enhance the photocatalytic H 2 evolution. Surface modification by metal ion has been considered a promising strategy to enhance the photocatalytic activity by extending optical response and improving charge separation and transportation. Here, univalent copper species were modified on ZnIn 2 S 4 photocatalyst via an in-situ photodeposition method, exhibiting a much higher H 2 evolution rate of 41.10 ± 3.43 mmol g −1 h −1 and an impressive apparent quantum efficiency (AQE) of 20.81% at 420 ± 15 nm. Our characterizations indicate that the surface modification by copper species can broaden light utilization as well as promote charge separation and transportation. Besides, the density functional theory (DFT) results further exhibit that the energy levels (LUMO and HOMO) for copper-surface modified ZnIn 2 S 4 present spatial separation, locating on the Zn-S and In-S layers, respectively, which can suppress the recombination of electron and hole and thus achieves higher photocatalytic H 2 evolution efficiency.