Oxygen Vacancy-Modified B-/N-Codoped ZnGa2O4 Nanospheres with Enhanced Photocatalytic Hydrogen Evolution Performance in the Absence of a Pt Cocatalyst

Abstract

Here, we report oxygen vacancy (VO)-modified B/N-codoped ZnGa2O4 (VO-B/N-ZGO) nanospheres, showing excellent photocatalytic H2 production even without a Pt cocatalyst, which is better than that obtained with VO-modified B-doped ZnGa2O4 (VO-B-ZGO) or N-doped ZnGa2O4 (N-ZGO) and as high as about three times of that achieved with the undoped ZnGa2O4 (ZGO) photocatalyst. The dramatically enhanced photocatalytic activity of VO-B/N-ZGO predominately originates from the improvement of charge separation and surface activation. Experimental characterization combined with the theoretical calculation method demonstrates that VO-B/N-ZGO can show effective charge compensation more easily through the interaction of oxygen vacancies, interstitial boron, and substitutional nitrogen; especially for the formation of a B–N bond, it avoids the presence of semioccupied states as new recombination centers in a doped photocatalyst. In addition, VO-B/N-ZGO rich in reactive sites is generated by oxygen vacancy-modified B/N-codopi...