AuPt alloy nanoparticles of 1 wt% supported on MnO₂-Mn₃O₄ heterostructures have been prepared by in situ transformation of α-MnO₂. They exhibit enhanced activity for aerobic photocatalytic glycerol oxidation under ambient conditions due to synergistic photothermal and photochemical catalytic effects, displaying 2.3 and 6.5 times enhancement compared to that of AuPt/Mn₃O₄ and AuPt/MnO₂, respectively.

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.