Bimetallic Synergy in Ultrafine Cocatalyst Alloy Nanoparticles for Efficient Photocatalytic Water Splitting

摘要

Herein, PtRu solid-solution alloy nanoparticles enable high-performance H_2evolution reaction cocatalysts through the transfer of knowledge from electrocatalysisto photocatalysis. Ultrafine PtRu alloy nanoparticles (1.0 ± 0.2 nmin diameter) are synthesized by using a chemical polyol method and used forelectro/photo-catalyses. Integration of PtRu nanoparticles with carbon and AldopedSrTiO_3 powders via liquid-phase adsorption and successive two-stepair and H_2 annealing ensures uniform deposition of PtRu alloy nanoparticles(<2 nm) with a solid-solution structure. The PtRu alloy nanoparticles exhibithigher electrocatalytic activity for the hydrogen evolution reaction thanmonometallic Pt counterparts. Modifying Al-doped SrTiO_3 with PtRu alloynanoparticles results in efficient photocatalytic overall water-splitting activitywith an apparent quantum yield of 65 at 365 nm and a solar-to-hydrogenenergy conversion efficiency of 0.45, which are the highest values amongSrTiO_3-based photocatalytic water splitting systems with Rh-free cocatalysts.Transient diffuse reflectance spectroscopy reveals that the PtRu nanoparticleshave a superior electron-capturing ability than the Pt counterparts, probablydue to the decreased work function of Pt by alloying with Ru. This work establishesa framework to elucidate catalytic trends and provides rational designguidance toward the development of bimetallic solid-solution nanoparticlesas cost-effective and highly active cocatalysts for overall water splitting.