Highly stable and durable ZnIn₂S₄ nanosheets wrapped oxygen deficient blue TiO₂(B) catalyst for selective CO₂...

Developing new and highly stable efficient photocatalysts is crucial for achieving high performance and selective photocatalytic CO₂ conversion. In this paper, we designed a one-dimensional oxygen-deficient blue TiO₂(B) (BT) catalyst for improved electron mobility and visible light accessibility. In addition, hexagonal ZnIn₂S₄ (ZIS) nanosheets with a low bandgap and great visible light accessibility are employed to produce effective heterostructures with BT. The synthesized materials are tested for photocatalytic conversion of CO₂ into solar fuels (H₂, CO and CH₄). The optimized composite yields 71.6 and 10.3 μmol g^-1h^-1 of CO and CH₄, three and ten times greater than ZIS, respectively. When ZIS nanosheets are combined with a one-dimensional oxygen-deficient BT catalyst, improved electron mobility and visible light accessibility are achieved, charge carriers are effectively segregated, and the transfer process is accelerated, resulting in efficient CO₂ reduction. The photocatalytic CO₂ conversion activity of the constructed BT/ZIS heterostructures is very stable over a 10-day (240-hour) period, and CO and CH₄ production rates increase linearly with time; however, as time goes on, the rates of H₂ production decrease. Further, a five-time recycling test confirmed this, revealing essentially equal activity and selectivity throughout the experiment. As a result, CO₂ to CO and CH₄ conversion has high selectivity and longer durability. The band structure of the BT/ZIS composite is determined using Mott-Schottky measurement, diffuse reflectance spectroscopy, and valence band X-ray photoelectron spectroscopy. This research demonstrates a novel approach to investigating effective, stable, and selective photocatalytic CO₂ reduction systems for solar-to-chemical energy conversion.