Structural and electronic properties of oxygen defective and Se-doped p-type BiVO4(001) thin film for the applications of photocatalysis

Abstract

Monoclinic BiVO 4 is being used as a photocatalyst due to its stability, cost-effectiveness, ease of synthesis, and narrow band gap. Although, the valence band maximum, VBM (∼−6.80 eV vs vacuum) of BiVO 4 is well below the redox potential of water but having less positive conduction band minimum, CBM (−4.56 eV vs vacuum), responsible for its low efficiency. We have carried out a comprehensive periodic density functional theory (DFT) simulations for the pristine, Oxygen defective (O v ) and Se doped BiVO 4 , to engineer not only its CB edge position but the overall photocatalytic and charge carrier properties. Our theoretical method has nicely reproduced the experimental data of pristine BiVO 4 , which encouraged us to elaborate further its O v and Se-doped characteristics. It is found that both the O v (1% Oxygen vacancy) and Se-doped BiVO 4 (1-2% Se) have ideal band edges, band gaps, and small effective masses of electrons and holes, responsible for high photocatalytic activities. Moreover, Se-doped BiVO 4 behave as p-type semiconductor. Finally, the photocatalytic water-splitting behaviour of the selected surfaces were counterchecked with water interaction, where the strong water adsorption energy of about ∼−38 to −50 kcal/mol, confirms and predicts their higher efficiencies compared to that of parent BiVO 4 .

Printable Photocatalyst Sheets Incorporating a Transparent Conductive Mediator for Z-Scheme Water Splitting

“…28 On the other hand, BiVO 4 :Mo is unable to produce hydrogen from water because its conduction band level is more positive than the reduction potential of H + to produce H 2 . [29][30][31] However, the simultaneous evolution of H 2 and O 2 occurred at a H 2 /O 2 ratio of 2:1 on the as-prepared SrTiO 3 :Rh/np-ITO/BiVO 4 :Mo sheet. These results suggest that H 2 and O 2 were evolved by two-step photoexcitation over the SrTiO 3 :Rh and BiVO 4 :Mo particles.…”

First-Principle Insight Into the Effects of Oxygen Vacancies on the Electronic, Photocatalytic, and Optical Properties of Monoclinic BiVO4(001)

“…Although several studies have explored the effects of Ovac on the crystal structure, adsorption energy and band structure of monoclinic BiVO 4 (m-BiVO 4 ) (Yuan et al, 2017 ; Ullah et al, 2018 ; Wang et al, 2020 ), studies that include both theoretical calculations and photocatalytic experiments are rare. In addition, in those studies, the effects of adsorption energy and electron distribution of Ovac on photocatalytic materials were studied using theoretical calculations.…”

Determination of the Intrinsic Defect at the Origin of Poor H2 Evolution Performance of the Monoclinic BiVO4 Photocatalyst Using Density Functional Theory

“…The 5d-electrons on Bi were not considered as valence electrons in Bi because they would not change the band gap and DOS characteristics as recently reported in the literature. 40 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 9 PBE functional since it yields accurate bonds and lattice parameters in computationally cheap method. The calculated lattice parameters of the relaxed structures are reported in Table 1.…”