Inter-plane 2D/2D ultrathin La2Ti2O7/Ti3C2 MXene Schottky heterojunctions toward high-efficiency photocatalytic CO2 reduction

Ascribing to incremental fossil fuels emissions, the utilization and conversion of CO 2 and development of renewable energy is globally essential and significative. Ultrathin 2D/2D heterojunctions with fast photo-generated electrons transmission channels illustrate a better strategy to improve photocatalytic activity. Herein, combing La 2 Ti 2 O 7 with metallic few-layered Ti 3 C 2 MXene to construct inter-plane 2D/2D heterojunction was in situ self-assembled through solvothermal method. Benefiting from the advantages including stability, conductivity, abundant active sites and formation of Schottky junctions, as expected, the ultrathin 2D/2D La 2 Ti 2 O 7 /Ti 3 C 2 MXene nanosheets presented much improved photocatalytic ability for CO 2 reduction to CO and CH 4 , which is about 4.6 and 11.4 times higher than that of mechanical mixed La 2 Ti 2 O 7 and Ti 3 C 2 MXene. fs-TAS and XPS provided direct evidence that the prominence of La 2 Ti 2 O 7 /Ti 3 C 2 MXene in photocatalytic CO 2 reduction reaction over other opponents should be attributed to the synergetic effect of efficient charge carrier mobility and formed 2D/2D Schottky heterojunction interfacial contact between La 2 Ti 2 O 7 and Ti 3 C 2 MXene. Intermediates revealed by in-situ DRIFTS and corresponding atomic-level DFT calculations confirmed the mechanism, pathways and selectivity for photocatalytic CO 2 conversion. This work expanded promising prospects arouses new impetus for deepening the prehension of the mechanism of photocatalytic CO 2 reduction, designing and fabrication of Schottky heterojunctions for application in conversion and utilization of CO 2 .