Unexpected catalytic performance in silent tantalum oxide through nitridation and defect chemistry.

This work reports on the preparation of a noble-metal-free and highly active catalyst that proved to be an efficient and green reductant with renewable capacity. Nitridation of a silent Ta1.1O1.05 substrate led to the formation of a series of TaOxNy hollow nanocrystals that exhibited outstanding activity toward catalytic reduction of nitrobenzenes under ambient conditions. ESR and XPS results indicated that defective nitrogen species and oxygen vacancies at the surfaces of the TaOxNy nanocrystals may play synergetic roles in the reduction of nitrobenzenes. The underlying mechanism is completely different from those previously reported for metallic nanoparticles. This work may provide new possibilities for the development of novel defect-meditated catalytic systems and offer a strategy for tuning any catalysts from silent to highly reactive by carefully tailoring the chemical composition and surface defect chemistry.