Enhancing the heterojunction component-interaction by in-situ hydrothermal growth toward photocatalytic hydrogen evolution

Abstract

The in-situ synthesis method to construct a heterostructure with a tight binding interface can promote the separation and transfer of charges, which is particularly crucial for improving photocatalytic efficiency. Herein, we have successfully synthesized a high-efficiency photoreduction catalyst by in situ growing a layer of flaky nickel chromium layered double hydroxides nanosheets (LDH) on carbon nitride hexagonal tube (CN) in hydrothermal. The tube-flakes like CN-LDH heterostructures have enhanced hydrogen evolution efficiency (14.5 mmol h−1 g−1), which is about 4.7 times that of pure CN (2.7 mmol h−1 g−1) and much higher than that of LDH (0.06 mmol h−1 g−1). We attribute this performance improvement mainly to the close-knit heterostructure formed between LDH and CN. This tight combination strengthens the diffusion of self-charge between the two semiconductors to form a strong built-in electric field and band bending. Under the action of the built-in electric field (BIEF), the photogenerated charge can be efficiently separated and oriented fast transfer, thereby greatly improving the photocatalytic efficiency. This work constructs a tightly connected heterostructure photocatalyst through hydrothermal method, and uses the catalyst to convert high-efficiency solar energy into renewable energy.