Promoting photothermal catalytic N2 reduction through dynamic mass transfer and accelerated charge transfer dynamics

Abstract

The effective adsorption and mass transfer of N2 at the catalytic active site, along with efficient photogenerated charge transfer at the interface are the prerequisites for the photothermal catalysis N2 reduction. Here, the hydrophobic-hydrophilic biphasic heterojunction Bi2WO6/ Bi2Sn2O7 (BWSO-20) was prepared by solvothermal method, and a strong interfacial internal electric field (IEF) was formed. The effects of N2 dynamic mass transfer and interface charge transfer kinetics on the performance of photothermal catalytic N2 reduction (PTC-NRR) was investigated. The results from in-suit DRIFTS, DFT, and molecular dynamics simulations (MD) indicated that a biphasic structure enhanced the dynamic mass transfer of N2 in the hydrophobic phase (BSO) and H2O in the hydrophilic phase (BWO) simultaneously. Additionally, the IEF that accelerates the transfer kinetics of photo-generated charges. Therefore, more photo-generated electrons and holes could transfer to the surface of the hydrophobic/hydrophilic phase catalyst and undergo redox semi-reactions with N2 and H2O. The PTC-NRR reached 366.1 μmoL·g−1 when using BWSO-20 without adding sacrificial agent. This work provides a new way to achieve efficient photothermal N2 reduction based on the interfacial charge transfer kinetics accelerated by the interfacial internal electric field and the dynamic mass transfer enhanced by hydrophobic – hydrophilic two-phase heterojunction.