The interface electric field accelerated charge transfer kinetics of 1D/0D TiO2/Bi2Sn2O7 Z-scheme heterojunction with close contact interface significantly improves photothermal catalytic N2 reduction

Abstract

The slow kinetics of charge transfer and weak redox ability hindered the practical application of photocatalytic N2 reduction. Therefore, in this article, Bi2Sn2O7 nanoparticles were grown in situ on the surface of TiO2 nanorods using a solvothermal method to form a 1D/0D TiO2/Bi2Sn2O7 (TBSO-15) Z-scheme heterojunction with a tight contact interface. The results of density functional theory calculations (DFT) and Kelvin probe force microscopy (KPFM) indicated that the difference in Fermi levels led to spontaneous rearrangement of charges at the heterojunction interface and the formation of a strong interfacial electric field (IEF). IEF provided a powerful driving force for the spatial separation of photogenerated charges, accelerating charge transfer dynamics. Secondly, the Z-scheme migration pathway of photo-generated charges between TiO2 and Bi2Sn2O7 enhanced the redox ability of TBSO-15 and formed a spatially separated redox center. In addition, molecular dynamics simulations (MD) showed that the photothermal effect significantly promoted the dynamic diffusion of N2 and H2O, accelerating the chemical reaction kinetics. Therefore, the synergistic effect of the two significantly improved the performance of Photothermal catalytic N2 reduction (PTC-NRR). After simulating solar irradiation for 2 h, the PTC-NRR performance of TBSO-15 achieved 327.25 μmoL·g−1 in pure water, which was 19.7 times that of TiO2 and 4.2 times that of Bi2Sn2O7, respectively. This study provides a reference for the synergistic effect of charge space transfer dynamics and photothermal effect to promote PTC-NRR.