Single atom doping induced charge-specific distribution of Cu1-TiO2 for selective aniline oxidation via a new mechanism
Utilizing single atom sites doping into metal oxides to modulate their intrinsic active sites,achieving precise selectivity control in complex organic reactions,is a highly desirable yet challenging en-deavor.Meanwhile,identifying the active site also represents a significant obstacle,primarily due to the intricate electronic environment of single atom site doped metal oxide.Herein,a single atom Cu doped TiOz catalyst(Cu1-TiO2)is prepared via a simple"colloid-acid treatment"strategy,which switches aniline oxidation selectivity of TiO2 from azoxybenzene to nitrosobenzene,without using additives or changing solvent,while other metal or nonmetal doped TiO2 did not possess.Compre-hensive mechanistic investigations and DFT calculations unveil that Ti-O active site is responsible for triggering the aniline to form a new PhNOH intermediate,two PhNOH condense to azoxyben-zene over TiO2 catalyst.As for Cu1-TiO2,the charge-specific distribution between the isolated Cu and TiO2 generates unique Cu1-O-Ti hybridization structure with nine catalytic active sites,eight of them make PhNOH take place spontaneous dissociation to produce nitrosobenzene.This work not only unveils a new mechanistic pathway featuring the PhNOH intermediate in aniline oxidation for the first time but also presents a novel approach for constructing single-atom doped metal oxides and exploring their intricate active sites.
Single atom doped metal oxideAniline oxidationSelectivityNew mechanismActive site
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