Au Nanorod Photosensitized La₂Ti₂O₇ Nanosteps: Successive Surface Heterojunctions Boosting Visible to Near-Infrared Photocatalytic H₂ Evolution

Visible and near-infrared (NIR) light utilization is a high-priority target for solar-to-chemical energy conversion. In this work, a promising surface heterojunction-based plasmonic photocatalyst was developed by integrating Au nanorods (NRs) with La₂Ti₂O₇ nanosteps (Au-LTO NSP) for photocatalytic H₂ evolution in visible and near-infrared (NIR) regions. At wavelengths longer than 420 nm, Au-LTO NSP displayed H₂ production rate that was separately 2.4 and 4.7 times that of Au-LTO nanosheets (NS) and Au–P25 composites, using methanol as the sacrificial agent. At wavelengths longer than 780 nm, the enhancement was 2.3 and 5.8 times, respectively. The high apparent quantum efficiency (AEQ) of 1.4% at 920 nm irradiation makes the Au-LTO NSP photocatalyst especially efficient for the NIR light utilization. The broadband photocatalytic activity of Au-LTO NSP was mainly caused by longitudinal surface plasmon resonance of Au NRs, generating and injecting hot electrons into LTO NSP. Substantial electrons transferred from Au NRs to the (010) facets and then directionally migrated to the (012) facets of LTO NSP, as consequence of the successive (010) and (012) surface heterojunctions within a LTO NSP single particle. The unique step structure of LTO retarded the recombination of the photoinduced electrons and holes in Au NRs, showing the powerful role of the semiconductor surface heterojunction in favoring the plasmon-induced interfacial hot electron transfer