Cuprous ion (Cu⁺) doping induced surface/interface engineering for enhancing the CO₂ photoreduction capability of...

Solar-driven reduction of CO₂ and H₂O into fuels is a promising approach for addressing global warming and energy crisis. Herein, Cu⁺ doped W₁₈O₄₉ nanowires were prepared by a facile solvothermal method and applied in photocatalytic reduction of CO₂. The composition and structure of pristine and Cu⁺ doped W₁₈O₄₉ samples have been characterized. It was found that the morphology of W₁₈O₄₉ nanowires was changed with increasing amounts of dopant. The photocatalytic CO₂ reduction activity of W₁₈O₄₉ nanowires and the Cu⁺ doped W₁₈O₄₉ samples were evaluated using H₂O as reducing agent. The strategy of Cu⁺ doping not only could affect the band edge position and the surface wettability, but also influenced separation of the photogenerated electron-hole pairs. It was found that Cu⁺ doping could introduce oxygen vacancy and change the conduction edge to a more negative position for W₁₈O₄₉ nanowires, which might be beneficial for the activation of CO₂ and promote the following CO₂ reduction. Furthermore, the higher separation efficiency of photogenerated electron-hole pairs with Cu⁺ doping could contribute to the CO₂ photoreduction enhancement. In addition, the Cu⁺ doped W₁₈O₄₉ nanowires (Cu-W₁₈O₄₉-0.005) presented a relatively poor hydrophilic property, which might be beneficial for the adsorption of CO₂ molecules and contribute to its superior photocatalytic CO₂ reduction capability.