Investigation of W/Mo co-doping with multiple concentrations in photocatalyst BiVO4 by first-principles calculations. (1st August 2022)

• Record Type: Journal Article
• Authors: Shi, Jia; Zhang, Wenyu; Gu, Qiang
• Is Part Of: Solid state communications. Volume 351(2022)
• Publication Date: 2022-08-01
• Subjects: A. Semiconductors -- D. Electronic properties -- D. Photocatalytic properties; Solid state chemistry -- Periodicals; Solid state physics -- Periodicals; Chimie de l'état solide -- Périodiques; Physique de l'état solide -- Périodiques; 530.41
• DOI: 10.1016/j.ssc.2022.114794
• Languages: English
• ISSNs: 0038-1098

Abstract

Abstract: Monoclinic BiVO4, being a multicomponent metal oxide, exhibits superior solar-active performance than its tetragonal phase in photocatalysis. In order to obtain improved separations between photoinduced electrons and holes, electronic properties and photocatalytic activity of W/Mo co-doped BiVO4 with multiple W/Mo concentrations (W– α Mo–BiVO4 and β W–Mo–BiVO4 ( α, β = 1, 2, 3 ) ) were investigated using the GGA + U method based on density functional theory (DFT). According to the calculated formation energy, W– α Mo–BiVO4 composition is more stable than β W–Mo–BiVO4 if the amount of α is equal to β . The electronic structures of W– α Mo–BiVO4 and β W–Mo–BiVO4 ( α, β = 1, 2, 3 ) tend to have sharper valence band and flatter conduction band edges than those of pure BiVO4 . Multiple co-doping W/Mo configurations result in the formation of continuous impurity states, which is beneficial for photocatalysis response. Notably, the absorption peaks of W– α Mo–BiVO4 and β W–Mo–BiVO4 ( α, β = 1, 2, 3 ) emerge at the dominant photon flux segment corresponding to 0–1.23 eV, improving the solar light absorption and conversion. Moreover, the results of dielectric constant and carrier effective mass indicate that W and Mo co-doping with different concentrations in BiVO4 substantially enhance the separation of photoactive electron-hole pairs and the mobility velocities of charge carriers. The potentials vs. NHE strongly confirmed that W– α Mo–BiVO4 and β W–Mo–BiVO4 ( α, β = 2, 3 ) have abundant reduction potential to strengthen the capability of converting photogenerated e − into H2 O2 . Particularly, E C B (+0.43 eV vs. NHE) of 2W–Mo–BiVO4 possesses a more powerful reduction capability. Based on our results, W/Mo co-doping with multiple concentrations in BiVO4 (W– α Mo–BiVO4 and β W–Mo–BiVO4 ( α, β = 2, 3 ) ) are particularly suitable for solar-light-driven photocatalytic activity. Graphical abstract: By adopting GGA + U method within the framework of density functional theory to calculate formation energy, electronic and photocatalytic properties, W/Mo co-doping with multiple concentrations in BiVO4 significantly improve the performance of photocatalysis. Image 1 Highlights: GGA + U provides accurate description of electronic structures in W/Mo co-doped BiVO4 . The band edge position is regulated by co-doping W/Mo with multiple concentrations. W and Mo dopants extend light absorption capability to the dominant segment of photons flux in solar light spectrum. The separation of photoactive electron-hole pair is achieved by the contribution of W/Mo. Desired free charge carriers and ample reduction potentials are attained by calculating electronic band edge.