Developing highly efficient photocatalysts for CO₂ reduction remains a great challenge. The large band gap and poor charge carrier dynamics are the major factors limiting the performance of Bi₄Ti₃O₁₂ (BTO). Herein, a series of La-doped Bi₄Ti₃O₁₂ (BLa_xTO) nanosheets were synthesized and further modified by NaBH₄ hydrogenation to create surface defect-rich H-BLa_XTO nanosheets. Characterizations and theoretical calculations confirmed that the synergistic effect of La doping and hydrogenation significantly enhanced visible-light absorption, promoted charge separation, and improved the electron reduction capacity. When applied to photocatalytic CO₂ reduction, the H-BLa_0.2TO catalyst achieved a superior CH₃OH production rate of 7.90 μmol·g⁻¹·h⁻¹, which is 5.6 times higher than that of pristine Bi₄Ti₃O₁₂. Moreover, the H-BLa_0.2TO catalyst maintained excellent stability over four consecutive cycles. This study offers an integrated strategy for constructing high-performance bismuth-based photocatalysts through elemental doping and defect engineering.

We report a route to produce 1,4-dioxane from oxirane by using ZrO₂/TiO₂ as catalyst. The composite oxide ZrO₂/TiO₂ was prepared by a coprecipitation method and the catalytic performance was tested through the synthesis of 1,4-dioxane from oxirane in a pipe reactor. The X-ray diffraction (XRD) shows that ZrO₂ and TiO₂ are in crystal form. When the mass percentage of ZrO₂ is 25%, the composite oxide ZrO₂/TiO₂ presents as an amorphous form. The sample 25%ZrO₂/TiO₂ exhibits a specific surface area of 269.5 m²·g⁻¹ and pore volume of 1.34 mL·g⁻¹. The catalyst has 670 µmol·g⁻¹ of NH₃-TPD acid, and the characterization of ammonia infrared spectroscopy (NH₃-FTIR) shows that both Brønsted and Lewis acids are present on the surface of the catalyst. The reaction mechanism was analyzed according to the distribution of product. The test of catalytic performance showed 100.0% conversion of oxirane and 86.2% selectivity of 1,4-dioxane at the optimal operation conditions: atmospheric pressure, reaction temperature 75 °C and gaseous hourly space velocity of 1200.0 h⁻¹. The catalyst exhibits good catalytic performance stability after continuous use for 720 h.

The incorporation of Cu-species, leveraging their variable valence states, represents a promising strategy for enhancing photocatalytic CO ₂ reduction.