Enhanced Photocatalytic Activity of N-TiO2/WO3 Photoelectrode with Controlled Morphology and Mesoporous Structure

(3) By utilizing the dual action of ammonium metatungstate (H8N6O24W6) as a nitrogen source for N-doped TiO2 and as a precursor for WO3 in TiO2/WO3 composites, and titanium butoxide (C16H36O4Ti) as a precursor for TiO2, N-TiO2/WO3 photoelectrodes were successfully prepared with the addition of F127 as a template agent to control the morphology. SEM images showed an irregular nanoblock morphology on the surface of the photoelectrode, with the addition of F127 reducing the volume of the nanoblocks and providing more reactive sites for photocatalysis. EDS results indicated a uniform distribution of N, W, and Ti elements on the surface of the photoelectrode. Combined with TEM and XPS analysis, the (101) crystal face of TiO2 and the (002) crystal face of WO3 were combined, and the XPS peak of N element at 399.5 eV indicated that N was doped into TiO2 in the form of a chemical bond N-Ti-O. The isotherm types of 350nw, 400nw, 450nw photoelectrodes prepared with F127 were all type IV isotherms, with hysteresis loops of type H3, indicating the formation of mesoporous structures that facilitate interface reactions between the photoelectrode and electrolyte. At the optimum calcination temperature of 400 ﾰC, the 400nw photoelectrode had a specific surface area of 87.83 m2/g, which was 3.67 times higher than that of the non-F127 modified photoelectrode 2-5. The smaller band gap width (3.0 eV) and lower electrochemical interface resistance of the 400nw photoelectrode provided favorable conditions for its high photocatalytic performance. In the photoelectrochemical water oxidation test with MB-contaminated wastewater, the 400nw photoelectrode exhibited the best MB degradation performance (31%) and hydrogen (5.81 ﾵmol) and oxygen (5.94 ﾵmol) production efficiency due to its highest charge quantity of 0.461 C.