Photoelectrochemical solar energy conversion to electricity or fuels is often limited by the activity of photogenerated holes and electrons on photoelectrode surfaces, requiring modification with catalysts to improve efficiency. It is unclear, however, on what surface sites to optimally deposit catalysts, and to what extent the same surface sites, responsible for fuel-forming reactions, also cause recombination. Here we use charge-carrier-selective single-molecule super-resolution photoelectrocatalysis imaging to quantify the correlation between photogenerated hole and electron activities on semiconductor surfaces at nanometer resolution under photoelectrochemical water oxidation conditions. We further use sub-particle-level photocurrent-vs-potential measurements to define the relationship between water oxidation photocurrent and charge-carrier surface activities. Guided by hole and electron activity maps, site-selective catalyst deposition on individual semiconductor particles reveals the optimal sites for oxygen evolution catalysts, leading to a strategy for rationally engineering photoanodes with catalysts.

Reaction and photocurrent imaging of single semiconductor particles for solar water oxidation

254th National Meeting (2017)

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