Insight on the Contribution of Plasmons to Gold‐Catalyzed Solar‐Driven Selective Oxidation of Glucose under Oxygen

With the increasing concerns about pollution and reduction of energy demands, the use of solar energy to drive chemical transformations is becoming increasingly attractive. Within the context of sustainability, sunlight‐driven organic transformation of biomass feedstock, such as free carbohydrates, to obtain high added‐value products is an important topic in which the recent progress should contribute to the development of solar biorefineries. Among the variety of photocatalysts, gold nanoparticles (NPs) loaded onto large bandgap semiconductors represent the state of the art. Such catalysts are known to accelerate the targeted reaction upon plasmonic excitation. In addition, as noble metal NPs, they also hold an additional role related to surface catalysis, which has been exploited for aerobic oxidation of free sugars. Nevertheless, the respective contribution of each role during transformation is not well established. Herein, the enhancement of the O2‐mediated oxidation of free sugars using Au NPs on CeO2 under standard air mass 1.5G illumination conditions is reported. The results highlight that the plasmonic contribution of Au NPs is totally annihilated and this enhancement stems solely from a thermal activation process induced by NIR radiation from standard white‐light conditions. The utilization of solar energy to transform biomass feedstock is an important topic that brings to the forefront the concept of solar biorefineries. Herein, the enhancement of O2‐mediated gold‐catalyzed oxidation of free sugars using standard illumination conditions is presented. The results highlight that under these conditions, only thermal activation, and not the plasmonic effect, is responsible for the reaction enhancement under illumination.