Suppressing Photoinduced Charge Recombination via the Lorentz Force in a Photocatalytic System

Abstract

Suppressing the recombination of photogenerated charges is one of the most important routes for enhancing the catalytic performance of semiconductor photocatalysts. In addition to the built-in field produced by semiconductor heterostructures and the photo-electrocatalysis realized by applying an external electrical potential to photocatalysts assembled on electrodes, other strategies are waiting to be scientifically explored and understood. In this work, a Lorentz force-assisted charge carrier separation enhancement strategy is reported to improve the photocatalytic efficiency by applying a magnetic field to a photocatalytic system. The photocatalytic efficiency can be improved by 26% just by placing a permanent magnet beneath the normal photocatalytic system without any additional power supply. The mechanism by which the Lorentz force acts oppositely on the photogenerated electrons and holes is introduced, resulting in the suppression of the photoinduced charge recombination. This work provides insights into the specific role of the Lorentz force in suppressing the recombination of electron-hole pairs in their initial photogenerated states. This suppression would increase the population of charge carriers that would subsequently be transported in the semiconductor. It is believed that this strategy based on magnetic effects will initiate a new way of thinking about photoinduced charge separation.