Photoelectrochemical (PEC) water splitting converts solar light and water into oxygen and energy-rich hydrogen. WO3/BiVO4 heterojunction photoanodes perform much better than the separate oxide components, though internal charge recombination undermines their PEC performance when both oxides absorb light. Here we exploit the BiVO4 layer to sensitize WO3 to visible light and shield it from direct photoexcitation to overcome this efficiency loss. PEC experiments and ultrafast transient absorption spectroscopy performed by frontside (through BiVO4) or backside (through WO3) irradiating photoanodes with different BiVO4 layer thickness demonstrate that irradiation through BiVO4 is beneficial for charge separation. Optimized electrodes irradiated through BiVO4 show 40% higher photocurrent density compared to backside irradiation.

Enhanced Charge Carrier Separation in WO3/BiVO4 Photoanodes Achieved via Light Absorption in the BiVO4 Layer / I. Grigioni, A. Polo, M.V. Dozzi, K.G. Stamplecoskie, D.H. Jara, P.V. Kamat, E. Selli. - In: ACS APPLIED ENERGY MATERIALS. - ISSN 2574-0962. - 5:(2022 Oct 17), pp. 13142-13148. [10.1021/acsaem.2c02597]

Enhanced Charge Carrier Separation in WO3/BiVO4 Photoanodes Achieved via Light Absorption in the BiVO4 Layer

I. Grigioni
Primo
Investigation
;
A. Polo
Secondo
Conceptualization
;
M.V. Dozzi
Conceptualization
;
E. Selli
Ultimo
Writing – Review & Editing
2022

Abstract

Photoelectrochemical (PEC) water splitting converts solar light and water into oxygen and energy-rich hydrogen. WO3/BiVO4 heterojunction photoanodes perform much better than the separate oxide components, though internal charge recombination undermines their PEC performance when both oxides absorb light. Here we exploit the BiVO4 layer to sensitize WO3 to visible light and shield it from direct photoexcitation to overcome this efficiency loss. PEC experiments and ultrafast transient absorption spectroscopy performed by frontside (through BiVO4) or backside (through WO3) irradiating photoanodes with different BiVO4 layer thickness demonstrate that irradiation through BiVO4 is beneficial for charge separation. Optimized electrodes irradiated through BiVO4 show 40% higher photocurrent density compared to backside irradiation.
solar water oxidation; heterojunction; ultrafast transient absorption; photoactive layer thickness; filter effect
Settore CHIM/02 - Chimica Fisica
H20MCITNIF19ESELL_01 - Photoelectrochemical Solar Light Conversion into Fuels on Colloidal Quantum Dots Based Photoanodes (QuantumSolarFuels) - SELLI, ELENA - H20MCITNIF - Horizon 2020_Marie Skłodowska-Curie actions-Innovative Training Network (ITN)/Individual Fellowships (IF) - 2019
CAR_RIC14ESELL_M - Laboratorio multifunzionale e centro di formazione per la caratterizzazione e la sperimentazione preapplicativa di smart materials - SELLI, ELENA - CAR_RIC - Bandi Fondazione Cariplo - 2014
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/947050
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