Tandem Synergistic Catalysis on Cu–Pd/Bi₄Ti₃O₁₂ Nanorods Promoting Highly SelectivePhotoconversion of CO₂ to Ethyl Alcohol

The production of high-energy-density liquid fuels through the photoconversion of CO₂ offers a highly efficient method for storing sustainable solar energy for future use. Bi₄Ti₃O₁₂ (BTO) nanorods loaded with Cu–Pd nanoalloys were designed for the highly selective photoreduction of CO₂ to ethyl alcohol, using H₂O as the proton source. A tandem synergistic catalysis mechanism was proposed for this CO₂ photoconversion process. Initially, *CO intermediates are produced at the BTO nanorod, then transfer to neighboring Cu atoms, where they convert into ethyl alcohol via C–C bond formation on Pd atoms. Adjusting the ratio of Cu to Pd can modify the binding strength of the intermediates on the catalyst surface and the reaction kinetics of the CO₂ reduction, thus optimizing the efficiency and selectivity of the products. With the substitution of TiO₂, CeO₂, and SiO₂ for the BTO nanorod in similar systems, only CO or CH₄ were produced, highlighting the essential role of BTO in the present CO₂ photoconversion. Additionally, thermal-assisted photocatalysis was also tested to lower the free energy barrier for the formation of the *OCCO intermediate, crucial for ethyl alcohol production, and enhance charge separation in BTO, leading to a 2.7-fold improvement compared to that under light illumination alone. A photocatalytic CO₂ reduction device was well designed with a reaction area of 25 cm × 25 cm, providing a potential model for large-scale ethyl alcohol production from the photoconversion of CO₂. This research may pave the way for utilizing the synergistic effects of metal active sites and photocatalyst substrates to enhance the generation of multicarbon species from CO₂ reduction.