Defect engineering of two-dimensional WO 3 nanosheets for enhanced electrochromism and photoeletrochemical performance

Abstract The capability of introduction of oxygen vacancies in a controlled way has emerged as the heart of modern transition metal oxide semiconductor chemistry. As chemical defects, the oxygen vacancies have been proposed as electron donors, which are prone to increase carrier density and promote charge carrier separation. Herein, we have successfully prepared 2D WO 3 ultrathin nanosheets with abundant surface oxygen vacancies by a combination of facile solvothermal reaction and hydrogenation method. The resultant hydrogenated WO 3 ultrathin nanosheets exhibit remarkable electrochromism and photocatalytic performances compared with the non-hydrogenated samples, mainly due to their increased oxygen vacancies, narrowed band gap coupled with fast charge transfer and enhanced adsorption of visible light.