Photoinduced Electrogenerated Chemiluminescence Imaging of Plasmonic Photoelectrochemistry at Single Nanocatalysts

In this study, we proposed a novel imaging technique,photoinducedelectrogenerated chemiluminescence microscopy (PECLM), to monitorredox reactions driven by hot carriers on single gold nanoparticles(AuNPs) on TiO2. Under laser irradiation, plasmon-generatedhot carriers were separated by an electric field, leaving hot holeson the surface of AuNPs to drive ECL reactions. PECL intensity washighly sensitive to the number of hot carriers. Through quantitativeimage analysis, we found that PECL density on individual AuNPs decreasedsignificantly with an increase in particle diameter, indicating thatparticle size has a significant impact on photoelectrochemical conversionefficiency. For the first time, we verified the feasibility of PECLMin mapping the catalytic activity of single photocatalysts. PECLMopens a new prospect for the in situ imaging of photocatalysis ina high-throughput way, which not only facilitates the optimizationof plasmonic photocatalysts but also contributes to the dynamic studyof photocatalytic processes on micro/nanointerfaces.