Formation of active oxygen species on single-atom Pt catalyst and promoted catalytic oxidation of toluene

Catalytic oxidation of toluene over noble metal catalysts is a representative reaction for elimination of volatile organic compounds(VOCs).However,to fully understand the activation of molecular oxygen and the role of active oxygen species generated in this reaction is still a challenging target.Herein,MgO nanosheets and single-atom Pt loaded MgO(Pt SA/MgO)nanosheets were synthesized and used as catalysts in toluene oxidation.The activation process of molecular oxygen and oxidation performance on the two catalysts were contrastively investigated.The Pt SA/MgO exhibited significantly enhanced catalytic activity compared to MgO.The oxygen vacancies can be easily generated on the Pt SA/MgO surface,which facilitate the activation of molecular oxygen and the formation of active oxygen species.Based on the experimental data and theoretical calculations,an active oxygen species promoted oxidation mechanism for toluene was proposed.In the presence of H2O,the molecular oxygen is more favorable to be dissociated to generate•OH on the oxygen vacancies of the Pt SA/MgO surface,which is the dominant active oxygen species.We anticipate that this work may shed light on further investigation of t10.1007/s12274-020-2765-1he oxidation mechanism of toluene and other VOCs over noble metal catalysts.

One-Pot Synthesis of Bismuth Basic Nitrate-Bi_(2)MoO_(6) Photocatalyst for Selective Oxidation of Toluene

The key issues to improve the performance of photocatalysts for selective oxidation of toluene are promoting the migration and separation of charge carrier,and enhancing the generation of active oxygen species.It is known that the construction of compact heterojunction is an efficient protocol to inhibit photogenerated electron-hole recombination.In this work,a 2D-2D[Bi_(6)O_(6)(OH)_(3)](NO_(3))3·1.5H2O-Bi_(2)MoO_(6)(denoted as BBN-BMO)composite heterojunction has been prepared by one-step hydrothermal method for the first time.The tetragonal phase BBN in the composite plays the role of transferring electrons from the visible light activated orthorhombic phase BMO and promoting the generation of active·O_(2)^(-),the holes left in BMO are used to activate toluene and produce benzyl radical,thus greatly improving the photocatalytic performance for selective oxidation of toluene.The toluene conversion rate of BBN-BMO is 3466μmol·g^(-1)·h^(-1),which is three times that of pure BMO.The selectivity to benzalde-hyde is 94.2%.In addition,reasonable mechanism has been speculated based on a series of control experiments.