Synthesis and highly efficient photocatalysis applications of CdS QDs and Au NPs Co-modified KTaO3 perovskite cubes.

Perovskite structure has attracted interest for the past few years due to its prospects in photocatalysis. The exploration of efficient perovskite photocatalysts still receives much attention in the field of chemistry and materials science. Herein, KTaO3 cubes are first prepared by hydrothermal synthesis, then Au nanoparticles (NPs) are loaded on the cubes by photodeposition, and finally, CdS quantum dots (QDs) are modified on Au/KTaO3 cubes using an in situ growth method, and eventually tantalum-based photocatalysts in a ternary system are successfully prepared. The fabricated CdS/Au/KTaO3 reveals photocatalytic properties in hydrogen evolution and degradation of dyes. In particular, under the same conditions, the photocatalytic hydrogen evolution rate of the optimized 13%CdS/1.3%Au/KTaO3 (13% and 1.3% are the contents of CdS and Au in the composite photocatalyst, respectively) is 2.892 mmol g-1 h-1. Compared to those of bare KTaO3 and CdS, it is approximately 107-fold and 8.5-fold enhanced, respectively. And the sizes of CdS and Au in the photocatalyst are 4.21 and 15.07 nm. The increased photoactivity of the composite can be ascribed to the synergistic effect of several factors, such as: the Au NPs' surface plasma resonance (SPR) impact improves the production of hot electrons and the ability of KTaO3 to capture light; effective integration between CdS QDs and KTaO3 cubes forms a heterojunction and expands the absorption range of KTaO3 in the visible light spectrum, improving the utilization rate of visible light effectively. Hence, a co-modification strategy has been proposed for endowing KTaO3 perovskites with new structures and different functions, and it is expected to become a general strategy to find an illuminating strategy for achieving improvements and enhancements in the photocatalytic field.

Ultrathin Niobate Nanosheet Assembly with Au NPs and CdS QDs as a Highly Efficient Photocatalyst.

Niobate nanosheets have aroused widespread interest in recent years for their prospects in catalysis. The exploration of 2D niobate catalysis with stable and efficient properties is still the focus in chemistry and materials science. Herein, the successful fabrication of 2D CdS/Au/HNb3 O8 catalyst is demonstrated which revealed efficient photocatalytic properties in H2 evolution, oxidative self-coupling of amines to imines, and degradation of dyes. Especially the assembled architecture can give a rate of 5.85 mmol ⋅ g-1 ⋅ h-1 of photocatalytic H2 evolution, an ∼254-fold enhancement, compared with bare HNb3 O8 nanosheets under identical conditions. In accordance with density functional theory (DFT) and X-ray adsorption fine structure (XAFS) analyses, the vast improvements are benefited from efficient migration and separation of charge carriers. Besides, the surface plasma resonance (SPR) effect of Au NPs enhances the light harvesting capacity and boosts the generation of hot electrons, efficiently improving the visible-light absorption.