Usage of natural leaf as a bio-template to inorganic leaf: Leaf structure black TiO2/CdS heterostructure for efficient photocatalytic hydrogen evolution

Abstract Herein, first time we report that highly efficient sheet like leaf structure black TiO2 (LBT)/CdS hetero-structure (LBT/CdS). Photocatalytic hydrogen generation was tested for different material in the presence of visible light (λ ≥ 420 nm) irradiation. 10 wt% of LBT loaded CdS (10LBT/CdS) exhibit maximum photocatalytic H2 generation rate about ~10 mmol h−1 g−1, which is higher than the H2 production results of pristine CdS (6 mmol h−1 g−1) and leaf black-TiO2 5.1 mmol h−1 g−1) respectively. Detailed characterization revealed that higher photocatalytic activity was mainly attributed to enormous spatial transfer efficiency of photo-excited charge carriers at the hetero-junction between LBT and CdS in LBT/CdS. Additionally, introduction of 2D black leaf-TiO2 to CdS act as a mat and enhances the mobility of charge carriers. In addition, presence of anatase-rutile surface-phase junction in leaf TiO2 (synthesized at 750 °C) and more edges, steps and corners on the CdS synergistically increased the photocatalytic H2 generation and photocurrent response of LBT/CdS.