Light-Induced Chemiluminescence Microscopy for Imaging Heterogeneous Photo-Fenton-Type Activity on Individual Hematite Photocatalysts.

While chemiluminescence (CL) offers a promising method for assessing catalytic activity in chemical catalysis, a well-controlled assessment of the inherent heterogeneity of catalyst particles at a single-particle level remains challenging. Here, we report light-induced CL microscopy for imaging heterogeneous photocatalytic activity on individual photocatalysts in a spatiotemporally controlled manner. The CL microscopy approach is based on light-addressable catalysis to reveal the heterogeneous activity of photocatalysts at the single catalyst level with high controllability for CL emission. We also report, for the first time, the spatial heterogeneity of photo-Fenton-type activity of dendritic hematite within a single hematite photocatalyst, along with the unique activity distribution of the individual photocatalysts across a population of dendritic hematite structures of varying shapes and sizes.