Defect Management of SrNbO2N through Zn Modification for Promoted Photocatalytic Water Oxidation

With a superior light-response ability and a high dielectric constant, the perovskite oxynitride SrNbO2N was expected to be an efficient photocatalyst for solar water splitting. However, a high defect density that formed during its preparation process had inhibited its charge separation and decreased the photocatalytic activity. In this work, SrNbO2N was modified through a high concentration doping of Zn2+ at the B site to inhibit its defect formation and promote its photocatalytic oxygen evolution performance. The defect formation in Sr(Nb2/3Zn1/3)O3–xNy (SNZON) is inhibited due to the sacrificial reduction of zinc ions during the nitridation process. Benefiting from the successful inhibition of defect formation and the promoted surface hydrophobicity, a remarkably promoted water oxidation activity was achieved on the as-obtained SNZON photocatalyst and the apparent quantum efficiency at 420 ± 10 nm reaches about 2.4%. This work may endow a new solution toward the preparation of low-defect oxynitride semiconductors with enhanced solar to chemical energy conversion efficiency.