In-situ preparation of TiO2/N-doped graphene hollow sphere photocatalyst with enhanced photocatalytic CO2 reduction performance

Photocatalytic CO2 conversion efficiency is hampered by the rapid recombination of photogenerated charge carriers. It is effective to suppress the recombination by constructing cocatalysts on photocatalysts with high-quality interfacial contact. Herein, we develop a novel strategy to in-situ grow ultrathin N-doped graphene (NG) layer on TiO2 hollow spheres (HS) with large area and intimate interfacial contact via a chemical vapor deposition (CVD). The optimized TiO2/NG HS nanocomposite achieves total CO2 conversion rates (the sum yield of CO, CH3OH and CH4) of 18.11 μmol g−1 h−1, which is about 4.6 times higher than blank TiO2 HS. Experimental results demonstrate that intimate interfacial contact and abundant pyridinic N sites can effectively facilitate photogenerated charge carrier separation and transport, realizing enhanced photocatalytic CO2 reduction performance. In addition, this work provides an effective strategy for in-situ construction of graphene-based photocatalysts for highly efficient photocatalytic CO2 conversion.