Engineering of CdSe quantum dots for photocatalysis: Fundamentals and applications in CO₂ reduction and biomass photoreforming

Abstract

Photocatalytic conversion of CO₂ and biomass-derived substrates offers a promising route for coupling solar energy harvesting with sustainable fuel and chemical production. This review analyzes CdSe quantum dots (QDs) as photocatalysts by linking their size-dependent electronic structure and surface chemistry to reaction-level performance in CO₂ reduction and biomass photoreforming. Quantum confinement defines band-edge energetics and exciton behavior, whereas ligand environments, defect states, and surface reconstruction govern carrier extraction, interfacial redox transfer, and susceptibility to non-radiative loss. Performance is therefore determined not only by light absorption, but by the balance between charge separation, transport, surface utilization, and degradation pathways. Reported CdSe QD systems are examined across unsupported nanocrystals, supported dispersions, and heterojunction architectures to identify how interfacial contact, optical management, and mass transport influence activity, selectivity, and comparability. In CO₂ photoreduction, surface-state energetics, carrier delivery, and photocorrosion constrain both efficiency and product distribution; in biomass photoreforming, substrate complexity and adsorption geometry regulate oxidation pathways and coupling to reductive half-reactions. These relationships provide a basis for more rigorous benchmarking and mechanism-informed catalyst design.