Constructing Multifunctional Metallic Ni Interface Layers in the g-C3N4 Nanosheets/Amorphous NiS Heterojunctions for Efficient Photocatalytic H2 Generation

The construction of: exceptionally robust and high-quality semiconductor-cocatalyst heterojunctions remains a grand challenge toward highly efficient and durable solar-to-fuel conversion: Herein, novel graphitic carbon nitride (g-C3N4) nanosheets decorated with multifunctional metallic Ni interface layers and amorphous NiS cocatalysts were fabricated via a facile three-step process: the loading of Ni(OH)(2) nanosheets, high-temperature H-2 reduction, and further deposition of amorphous NiS nanosheets. The results demonstrated that both robust metallic Ni interface layers and amorphous NiS can be-utilized as electron cocatalysts to markedly boost the visible-light H-2 evolution over g-C3N4 semiconductor. The optimized g-C3N4-based photo catalyst containing 0.5 wt % Ni and 1.0.wt % NiS pteserited the highest hydrogen evolution of 515,mu mol g(-1)h(-1), which was about 2.8 arid 4.6 times as much as. those obtained on binary g-C3N4-1.0%NiS and g-C3N4-0.5%Ni, respectively. Apparently, the metallic Ni interface layers play Multifunctional roles in enhancing the visible-light H-2 evolution, which could first collect the photogenerated electrons from g-C3N4, and then accelerate the surface H-2-evolution reaction kinetics over amorphous NiS cocatalysts. More interestingly, the synergetic-effects of metallic Ni and amorphous NiS dual-layer electron cocatalysts could also improve the TEOA-oxidation capacity through upshifting the VB levels of g-C3N4. Comparatively speaking, the multifunctional metallic Ni layers are dominantly favorable for separating and transferring photoexcited charge carriers from g-C3N4 to amorphous, NiS cocatalysts owing to the formation of Schottky junctions, whereas the amorphous NiS nanosheets are mainly advantageous for decreasing the thermodynamic overpotentiali, for surface H-2-evolution reactions: It is hoped that the implantation of multifunctional metallic interface layers can provide a versatile approach to enhance the photocatalytic H-2 generation over different semiconductor-cocatalyst heterojunctions.