Bi single-atom decorated Cu/Cu₂O heterostructure via spray pyrolysis for 100% selectivity in photocatalytic CO production

Photocatalytic CO₂ reduction is a promising approach for mitigating climate change and facilitating sustainable energy conversion. However, designing catalysts with high activity and selectivity remains a fundamental challenge. In this study, we present a scalable and highly controllable two-step synthesis process consisting of spray pyrolysis and subsequent thermal reduction to develop a Bi single-atom-decorated Cu/Cu₂O heterostructure (Bi SA-Cu/Cu₂O). This approach enables the precise, atomically dispersed anchoring of Bi sites while inducing the formation of oxygen vacancies and regulating the Cu⁰/Cu⁺ multi-phase interface. The optimized catalyst achieves a CO production rate of 183.46 μmol·g⁻¹·h⁻¹, which is twice that of pre-reduced Bi SA-CuO. It also exhibits nearly 100% selectivity toward CO. Combined experimental and theoretical studies reveal that the atomic dispersion of Bi coupled with oxygen vacancies significantly enhances CO₂ adsorption. Furthermore, the metallic Cu and semiconducting Cu₂O phases work together to modulate the reaction pathway, lowering the energy barrier for *CO formation while increasing the energy barrier for *COOH hydrogenation and promoting CO desorption. This work presents a scalable synthetic strategy for the precise fabrication of single-atom-decorated heterostructures, providing deep mechanistic insights into the design of highly selective photocatalysts for CO₂ conversion. © 2026 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.