Heterostructured Photocatalysts of Ni²⁺ Doped CdS Quantum Dots and β-Pb_0.33V₂O₅ Nanowires: Towards Selective CO₂ Reduction

Solar photocatalytic reduction of carbon dioxide (CO₂) to valuable products such as carbon monoxide, methane, and ethanol has become an appealing approach to mitigate the deleterious impact of the combustion of fossil fuels. Quantum dots (QDs), visible light-sensitive nanomaterials, have been widely studied for converting solar energy into chemical energy due to their light-harvesting properties, compositional tunability, and size-dependent energetics. However, bare QDs suffer from low selectivity toward the reduction of CO₂. To improve their catalytic activity, we have doped QDs with nickel(II) cations and interfaced them with ternary metal-intercalated vanadium oxide nanowires (NWs). Within the resulting heterostructures, QDs act as a charge donor, and the NWs exhibit intercalative mid-gap states functioning as a charge acceptor. Although our collaborative team has previously studied this type of heterostructure for hydrogen evolution and water splitting, they remain unexplored for CO₂photoreduction. This presentation will cover the preparation and characterization of heterostructures consisting of cysteine-capped nickel(II)-doped CdS QDs (cys-NiCdS QDs) interfaced with β-Pb_0.33V₂O₅ NWs. The heterostructures are envisioned as a system to selectively reduce CO₂ under white-light illumination. This presentation will highlight recent results from materials synthesis and characterization, photophysical and photoelectrochemical assessment of excited-state charge transfer, and photocatalysis using gas chromatography (GC) for product characterization.