Hierarchical hyper-branched titania nanorods with tuneable selectivity for CO₂ photoreduction

Utilising captured CO₂ and converting it into solar fuels can be extremely beneficial in reducing the constantly rising CO₂ concentration in the atmosphere while simultaneously addressing energy crisis issues. Hence, many researchers have focused their work on the CO₂ photoreduction reaction for the last 4 decades. Herein, the titania hyper-branched nanorod (HBN) thin films, with a novel hierarchical dendritic morphology, revealed enhanced CO₂ photoreduction performance. The HBNs exhibited enhanced photogenerated charge production (66%), in comparison with P25 (39%), due to the unique hyper-branched morphology. Furthermore, the proposed HBN thin films exhibited a high degree of control over the product selectivity, by undergoing a facile phase-altering treatment. The selectivity was shifted from 91% towards CO, to 67% towards CH₄. Additionally, the HBN samples showed the potential to surpass the conversion rates of the benchmark P25 TiO₂ in both CO and CH₄ production. To further enhance the selectivity and overall performance of the HBNs, RuO₂ was incorporated into the synthesis, which enhanced the CH₄ selectivity from 67% to 74%; whereas the incorporation of CuO revealed a selectivity profile comparative to P25.