Charge steering in ultrathin 2D nanomaterials for photocatalysis

Abstract

During the photocatalytic reaction, charge carriers play a dominant role in affecting the entire catalytic processes. Accordingly, recent endeavours on charge steering in ultrathin 2D photocatalysts to achieve high photocatalytic efficiency from the aspects of increasing charge generation, boosting charge transport and separation, suppressing charge recombination, and accelerating reaction kinetics are reviewed. Diverse strategies for effective tuning based on ultrathin 2D photocatalysts have been thoroughly discussed. Specifically, for charge generation, disorder engineering, doping, and plasmonic engineering can be effective approaches for extending the absorption range, while thickness control, crystal phase engineering, and molecular incorporation can increase the absorption intensity. For charge transport and separation, tuning the morphology, electrical conductivity, internal electric field and polarization is demonstrated to be able to boost bulk charge separation. Strategies like surface defect engineering, surface modification, incorporation of water-soluble molecular co-catalysts and shortening the surface migration distance are employed for boosting surface charge separation. Subsequently, strategies like constructing 2D/2D heterostructures, Z-scheme systems, in-plane heterojunctions and Moiré superlattices are presented to suppress charge recombination. Finally, surface polarization, co-catalyst modification, single atom engineering, crystal facet engineering, and vacancy engineering are summarized to accelerate reaction kinetics. Moreover, concluding remarks and perspectives on the future exploration of charge manipulation in ultrathin 2D photocatalysts are presented.