Point-to-face Z-scheme junction Cd0.6Zn0.4S/g-C3N4 with a robust internal electric field for high-efficiency H2O2 production

Photocatalytic H2O2 evolution has ignited a remarkable spark by virtue of its outstanding strengths of safety, greenness and low cost, while severely hindered by the grievous photoinduced carriers' recombination and sluggish charge migration. Here, we anchored the Cd0.6Zn0.4S solid solution nanoparticles on ultrathin g-C3N4 for constructing a point-to-face configurated Z-scheme junction via an in situ growth strategy. Such a unique point-to-face structure not only benefits fast interfacial charge migration, but also hinders the agglomeration of Cd0.6Zn0.4S nanoparticles. In situ Kelvin-probe force microscopy (KPFM) results and density functional theory (DFT) calculations along with other advanced characterization studies collectively unfold the presence of a strong internal electric field (IEF) between Cd0.6Zn0.4S nanoparticles and ultrathin g-C3N4, derived from the band potential difference and intimate contact, which serves a robust driving force to markedly accelerate direct Z-scheme charge transfer and carriers' separation. The Z-scheme junction also favors maintaining a strong redox potential, and effectively inhibits the recombination of photoinduced carriers. Thus, point-to-face Z-scheme junction Cd0.6Zn0.4S/ultrathin g-C3N4 exhibits a remarkable photocatalytic H2O2 yield of 1098.5 mu mol g(-1) h(-1), exceeding the majority of CN-based and sulfide-based photocatalysts. This study puts forward promising ideas in manufacturing a Z-scheme junction with a powerful IEF for high-performance photocatalytic H2O2 generation.