Single-particle exciton-initiated photo-catalytic reaction mapping on defective cuprous oxide

Although the exciton-triggered photocatalysis has recently been confirmed, so far it is limited to the low-dimensional semiconductors, and the characterization approaches are impossible to image and characterize the photo-catalytic reaction on single semiconductor photocatalysts. Herein by combining dark-field microscopy with 3, 3′, 5, 5′-tetramethylbenzidine as the chromogenic probe, we visually map the exciton-initiated photo-catalytic reaction on defective Cu2O microcrystals in real time at the single-particle level. Single-particle imaging results reveal the heterogeneity in reactivity among different individuals and at different regions within the same microcrystal. Moreover, the reaction rate constant of this photocatalytic reaction is determined as well. The theoretical simulations suggest that the introduction of Mn2+ can modulate the electronic structure and enhance the oxygen affinity of Cu2O, facilitating the production of 1O2. This high spatio-temporal-resolution imaging approach is general, which is also appropriate for investigating the exciton effects on Fe2+-doped Cu2O microcrystals. [Display omitted] •The exciton-initiated photo-catalytic reaction on single defective Cu2O microcrystals is visually mapped.•Single-particle imaging results reveal the heterogeneity in reactivity.•This high spatio-temporal-resolution imaging approach is general.