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

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 H 2 O. Furthermore, theoretical calculations indicated that the charge transfer and local electric field could stretch the O–H bonds of the adsorbed H 2 O, 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.