Articolo in rivista, 2020, ENG, 10.3390/surfaces3010010

Multilayer WO3/BiVO4 Photoanodes for Solar-Driven Water Splitting Prepared by RF-Plasma Sputtering

Pedroni Matteo; Chiarello Gian Luca; Vassallo Espedito; Selli Elena

CNR ISTP, Istituto per la Scienza e Tecnologia dei Plasmi, Milano, Italy; Dipartimento di Chimica, Università degli Studi di Milano, Italy.

A series of WO3, BiVO4 and WO3/BiVO4 heterojunction coatings were deposited on fluorine-doped tin oxide (FTO), by means of reactive radio frequency (RF) plasma (co)sputtering, and tested as photoanodes for water splitting under simulated AM 1.5 G solar light in a three- electrode photoelectrochemical (PEC) cell in a 0.5 M NaSO4 electrolyte solution. The PEC performance and time stability of the heterojunction increases with an increase of the WO3 innermost layer up to 1000 nm. A two-step calcination treatment (600 °C after WO3 deposition followed by 400 °C after BiVO4 deposition) led to a most performing photoanode under back-side irradiation, generating a photocurrent density of 1.7 mA cm-2 at 1.4 V vs. SCE (i.e., two-fold and five-fold higher than that generated by individual WO3 and BiVO4 photoanodes, respectively). The incident photon to current efficiency (IPCE) measurements reveal the presence of two activity regions over the heterojunction with respect to WO3 alone: The PEC efficiency increases due to improved charge carrier separation above 450 nm (i.e., below the WO3 excitation energy), while it decreases below 450 nm (i.e., when both semiconductors are excited) due to electron-hole recombination at the interface of the two semiconductors.

Surfaces (Basel) 3 (1), pp. 105–115

Keywords

WO3/BiVO4 heterojunction, RF-plasma sputtering, photocatalytic water splitting, photoelectrochemical cell

CNR authors

Pedroni Matteo, Vassallo Espedito

CNR institutes

ISTP – Istituto per la Scienza e Tecnologia dei Plasmi

ID: 422828

Year: 2020

Type: Articolo in rivista

Creation: 2020-05-25 13:55:33.000

Last update: 2023-02-03 16:54:09.000

External IDs

CNR OAI-PMH: oai:it.cnr:prodotti:422828

DOI: 10.3390/surfaces3010010

ISI Web of Science (WOS): 000717477600001