Plasmon-Enhanced Water Activation for Hydrogen Evolution from Ammonia-Borane Studied at a Single-Particle Level

Abstract

Understanding the plasmon-enhanced water activation mechanism is crucial for improving the catalytic activity for ammonia–borane (AB) dehydrogenation. Here, the water activation process is explored at both single-particle and ensemble levels. Kinetic analysis of AB dehydrogenation on Pt–Au nanorods (NRs), especially kinetic isotope experiments, confirmed that water activation is the rate-determining step. Importantly, the activation of water molecules by energetic charge carriers was clarified by in situ single-particle photoluminescence (PL) measurements. The PL quenching phenomenon of Pt–Au NRs (not Au NRs) was observed when in contact with water molecules, implying the transfer of hot electrons to H2O. Furthermore, theoretical calculations indicated that the charge transfer and local electric field could stretch the O–H bonds of the adsorbed H2O, leading to the activation of the O–H bond. This work provides an advanced understanding of the details of plasmon-enhanced bond activation and paves a potential route to increase the catalytic rate of involving water activation.