Photothermally Enhanced Photocatalytic Glycerol Oxidation on AuPt/MnO2-Mn3O4

Abstract

Photocatalytic valorization of glycerol to value-added chemicals under ambient conditions is a promising approach for economically feasible and environmentally friendly biomass utilization. Herein, the successful synthesis of ≈2.6 nm AuPt alloy nanoparticles supported on MnO₂-Mn₃O₄ heterostructures via in situ transformation of α-MnO₂ is reported. Selective aerobic photocatalytic glycerol oxidation toward value-added C3 products has been achieved with AM 1.5G light irradiation under ambient conditions on these as synthesized 1 wt% AuPt/MnO₂-Mn₃O₄, which displays 2.3 and 6.5 times enhancement compared to that of AuPt/Mn₃O₄ and AuPt/MnO₂. A 74% overall C3 product selectivity (60% in terms of glyceric acid) has been achieved at 75% glycerol conversion after 4 h of photocatalytic reaction. Investigation results reveal that the formation of MnO₂-Mn₃O₄ heterostructures combines the local photothermal heating (primarily on MnO₂) synergistically with the photochemical catalysis (on Mn₃O₄), thus achieving enhanced photocatalytic glycerol oxidation. This study may provide guidance for future catalyst design, where photon-driven photocatalysis with phonon-driven photothermal effect can be seamlessly integrated to achieve maximal solar energy utilization and high photocatalytic efficiency.