Porous Defective Bi/Bi3NbO7 Nanosheets for Efficient Photocatalytic NO Removal under Visible Light

Abstract

Since conventional techniques are ineffective for NO removal at low concentrations, photocatalysis has become attractive in this regard, recently. However, in practice, photocatalytic NO removal has drawbacks such as limited light absorption and the proclivity of producing toxic by-products. To address these issues, novel defective Bi/Bi3NbO7 structures with good porosity were fabricated by a solvothermal method and used for enhanced photocatalytic NO removal under visible light irradiation. The morphological and structural properties of the prepared materials were comprehensively analyzed. The optimal photocatalytic activity of pore-defective Bi/Bi3NbO7 for NO removal was 60.3%, when the molar ratios of urea and Bi(NO)3•5H2O to pristine Bi3NbO7 were 1:25 and 1:2, respectively, under the following operational conditions: NO concentration of 700 ppb, catalyst dosage of 50 mg and irradiation time of 14 min. The induced defects and the surface plasmon resonance (SPR) effect of Bi nanodots made remarkable contributions to improving the photocatalytic NO removal as well as inhibiting the toxic byproduct NO2. The photocatalytic NO removal pathway over the prepared photocatalysts was further mechanistically clarified taking advantage of EPR results and scavenging experiments. Considering the increased NO generation in the atmosphere, this work may provide novel insights for designing effective porous photocatalysts to treat gaseous toxic pollutants.