The three-dimensionally ordered microporous CaTiO₃ coupling Zn_0.3Cd_0.7S quantum dots for simultaneously enhanced photocatalytic H₂ production and glucose conversion

Glucose conversion assisted photocatalytic water splitting technology to simultaneously produce H₂ and high value-added chemicals is a promising method for alleviating the energy shortage and environmental crisis. In this work, we constructing type II heterojunction by in-situ coupling Zn_0.3Cd_0.7S quantum dots (ZCS QDs) on three-dimensionally ordered microporous CaTiO₃ (3DOM CTO) for photocatalytic H₂ production and glucose conversion. The DFT calculations demonstrate that substitution of Zn on the Cd site improves the separation and transmission of photogenerated carriers. Therefore, 3DOM CTO-ZCS composite exhibits best H₂ production performance (2.81 mmol g^-1h⁻¹) and highest apparent quantum efficiency (AQY) (5.56 %) at 365 nm, which are about 47 and 18 times that of CTO nanoparticles (NPs). The improved catalytic performance ascribed to not only good mass diffusion and exchange, highly efficient light harvesting of 3DOM structure, but also the efficient charges separation of type Ⅱ heterojunction. The investigation on photocatalytic mechanism indicates that the glucose is mainly converted to gluconic acid and lactic acid, and the control reaction step is gluconic acid to lactic acid. The selectivity for gluconic acid on 3DOM CTO-ZCS is 85.65 %. Our work here proposes a green sustainable method to achieve highly efficient H₂ production and selective conversion of glucose to gluconic acid.