Elucidating the role of surface states of BiVO4 with Mo doping and a CoOOH co-catalyst for photoelectrochemical water splitting

Yalavarthi R, Zbořil R, Schmuki P, Naldoni A, Kment Š (2021)

Publication Type: Journal article

Publication year: 2021

Journal

Journal of Power Sources Elsevier

Book Volume: 483

Article Number: 229080

DOI: 10.1016/j.jpowsour.2020.229080

Abstract

Bismuth vanadate (BiVO4) is a promising material for photoelectrochemical (PEC) water splitting, however, its PEC performance is limited by the high surface and bulk charge recombination rates. Here we present a comprehensive study to elucidate a recombination phenomenon of BiVO4 that arises with Mo doping. The Mo doping produces multiple effects including the formation of MoOx (reduced form of Mo6+) species and oxygen vacancies (VOs) on the surface of the BiVO4 that work in tandem with V4+ species (and MoOx) acting as surface-active intermediates (i-SS) providing improved hole transfer to the electrolyte. In contrast, in the absence of V4+ species, the VOs can act as recombination centers (r-SS). Further, CoOOH co-catalyst coating is used to minimize such recombination centers. Eventually, a photocurrent enhancement of ~37 times (1.1 mA/cm2 at 1.23 V vs. RHE) and a cathodic shift in onset potential of ~500 mV compared to that of pristine BiVO4 (0.03 mA/cm2 at 1.23 V vs. RHE) is obtained. We carried out in-depth PEC analysis using hole scavenger measurements, PEC impedance spectroscopy, and intensity-modulated photocurrent spectroscopy to elucidate the effect of the surface reduction process upon doping, the impact of Vos, MoOx species and CoOOH layer on the enhanced PEC performance.

Authors with CRIS profile

Patrik Schmuki Lehrstuhl für Werkstoffwissenschaften (Korrosion und Oberflächentechnik)

Involved external institutions

Palacky University Olomouc / Univerzita Palackého v Olomouci CZ Czech Republic (CZ)

How to cite

APA:

Yalavarthi, R., Zbořil, R., Schmuki, P., Naldoni, A., & Kment, Š. (2021). Elucidating the role of surface states of BiVO4 with Mo doping and a CoOOH co-catalyst for photoelectrochemical water splitting. Journal of Power Sources, 483. https://doi.org/10.1016/j.jpowsour.2020.229080

MLA:

Yalavarthi, Rambabu, et al. "Elucidating the role of surface states of BiVO4 with Mo doping and a CoOOH co-catalyst for photoelectrochemical water splitting." Journal of Power Sources 483 (2021).

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