Steering accessible oxygen vacancies for alcohol oxidation over defective Nb2O5 under visible light illumination

We provide a distinct understanding on the role of oxygen vacancies (OVs) for visible light-triggered aerobic oxidation of alcohols via comparative studies on three kinds of Nb2O5, i.e., undoped, Ti-doped and Ce-doped Nb2O5. With benzyl alcohol and 5-hydroxymethylfurfural as representative alcohol substrates, we show that fast alcohol oxidation with high selectivity can be achieved on these doped Nb2O5 containing abundant OVs. However, the functionality of OVs is dependent on the properties of dopants as Ce-doped Nb2O5 exhibits a better performance than Ti-doped one. Investigations indicate that the Ce dopants incur little distortion to the structure of Nb2O5 and induce more accessible OVs than Ti dopants for the dissociative chemisorption of alcohol molecules which supports favorable interfacial electron migration process. The present work not only reveals the difference of oxygen vacancies caused by varied metal doping but provides a unique insight in the relation between OVs structure and photocatalytic alcohol oxidation.