One‐Dimensional Single‐Crystal Mesoporous TiO2 Supported CuW6O24 Clusters as Photocatalytic Cascade Nanoreactor for Boosting Reduction of CO2 to CH4

Abstract

AbstractConstructing nanoreactors with multiple active sites in well‐defined crystalline mesoporous frameworks is an effective strategy for tailoring photocatalysts to address the challenging of CO2 reduction. Herein, one‐dimensional (1‐D) mesoporous single‐crystal TiO2 nanorod (MS‐TiO2‐NRs, ≈110 nm in length, high surface area of 117 m2 g−1, and uniform mesopores of ≈7.0 nm) based nanoreactors are prepared via a droplet interface directed‐assembly strategy under mild condition. By regulating the interfacial energy, the 1‐D mesoporous single‐crystal TiO2 can be further tuned to polycrystalline fan‐ and flower‐like morphologies with different oxygen vacancies (Ov). The integration of single‐crystal nature and mesopores with exposed oxygen vacancies make the rod‐like TiO2 nanoreactors exhibit a high‐photocatalytic CO2 reduction selectivity to CO (95.1%). Furthermore, photocatalytic cascade nanoreactors by in situ incorporation of CuW6O24 (W–Cu) clusters onto MS‐TiO2‐NRs via Ov are designed and synthesized, which improved the CO2 adsorption capacity and achieved two‐step CO2–CO–CH4 photoreduction. The second step CO‐to‐CH4 reaction induced by W–Cu sites ensures a high generation rate of CH4 (420.4 µmol g−1 h−1), along with an enhanced CH4 selectivity (≈94.3% electron selectivity). This research provides a platform for the design of mesoporous single‐crystal materials, which potentially extends to a range of functional ceramics and semiconductors for various applications.