Photoenhanced Electrocatalytic Hydrogen Evolution Accelerated Dominantly by the Hot Electrons from Intraband Transition rather than Interband Transition

Plasmonic materials enabling sunlight as an energy input to catalyze the hydrogen evolution reaction (HER) have become the research focus of artificial photosynthesis. Upon visible photoexcitation, there are both intraband transition and interband transition hot carriers generated, and which of them dominates the catalytic reaction remains elusive. Here, the contributions of hot electrons from intraband and interband transitions to the photoelectrocatalytic HER on plasmonic Au triangle nanoprisms (AuTNPs) have been studied. Compared with the dark reaction, the exchange current density increases by 9-fold and 3-fold under intraband and interband excitation, respectively, which is attributed to the higher energy level of intraband transition hot electrons. By calculation of the reaction activation energy with and without illumination, the contributions of the hot electrons from the two photoexcitation modes to the photoenhanced electroreduction reaction (PEER) are quantitatively analyzed, proposing the general standard to measure the effect of different hot electrons in different reactions.