Synthesis of Bi₂WO₆ photoanode on transparent conducting oxide substrate with low onset potential for solar water splitting

Abstract

High conduction band of Bi2WO6, thus low onset potential of Bi2WO6/Co-Pi photoanode, is favourable for overall water splitting at zero bias potential when it combines with a silicon photocathode.

Recent Advances in Bismuth‐Based Nanomaterials for Photoelectrochemical Water Splitting

“…RHE BiVO 4 film [160] spray pyrolysis Co-Pi and Wd oping0 .5 m K 2 SO 4 in phosphate buffer 2.3 mA cm À2 at 1.23V vs. RHE BiVO 4 island [143] spin coating WO 3 and TiO 2 0.1 m Na 2 SO 4 4.2 mA cm À2 at 1.23V vs. RHE BiVO 4 island [165] Co-magnetron sputtering Mo 0.5 m Na 2 SO 4 with 0.1 m phosphate buffer 1.2 mA cm À2 at 1.23V vs. RHE BiVO 4 shell [166] drop casting SnO 2 :Sb phosphate bufferwith 1 m Na 2 SO 4 3.9 mA cm À2 at 0.6 V vs. RHE BiVO 4 core-shell [132] electrodepositionWO 3 and Co-Pi potassium phosphate buffer6.722 mA cm À2 at 1.23Vvs. RHE Bi 2 WO 6 inverseo pal [89] evaporationi nduced self-assemblynone 1 m Na 2 SO 4 0.25mAcm À2 at 0.8 V vs. Ag/AgCl Bi 2 WO 6 agglomerated nanoporous particles [92] electrochemical methodf ollowed by coating and thermal annealing none 0.1 m borate buffer,p H9 0.1 mA cm À2 at 0.99V vs. RHE Bi 2 WO 6 nanorod arrays [33] hydrothermalCo-Pi 0.5 m Na 2 SO 4 30 mAcm À2 at 1.2 V vs. RHE Bi 2 WO 6 2D arrays [90] self-assembly none 1 m NaOH6 10 À5 Acm À2 at 0.4 Vv s. Ag/AgCl Bi 2 MoO 6 nanosheets [167] metal-assisted chemical etchinga nd hydrothermal growth Fe x Ni 1Àx O/Si 0.5 m potassiump hosphate 0.98mAcm À2 at 1.2 V vs. Ag/AgCl Bi 2 MoO 6 nanosheets [123] microwave-assistedu ltrasonics eparation WO 3 0.1 m Na 2 SO 4 2.2 mA cm À2 at 0.8 V vs. SCE Bi 2 MoO 6 fused quasispherical nanoparticles [126] anodization of Mo foil and subsequent hydrothermal MoO 3 0.1 m Na 2 SO 4 2.75mAcm À2 at 0.4 V vs. Ag/AgCl Bi 2 MoO 6 nanorodarray [168] hydrothermalBiVO 4 0.1 m Na 2 SO 4 250 mAcm À2 at 0.8 V vs. SCE BiFeO 3 nanoparticles [101] low-pressure CVD Ni-B 1 m potassium borate 0.72mAcm À2 at 1V vs. Ag/AgCl BiFeO 3 triangular nanopillers [147] pulsed laser deposition Fe 2 O 3 0.5 m Na 2 SO 4 0.19mAcm À2 at 0.6 V vs. Ag/AgCl BiFeO 3 [35] chemical solution deposition BiVO 4 0.1 m potassiump hosphate buffer 0.63mAcm À2 at 0.6 V vs. Ag/AgCl CuBi 2 O 4 agglomerated nanoparticles [104] drop casting none 0.3 m K 2 SO 4 and 0.2 m phosphate buffer/30% H 2 O 2 (4:1 v/v) 0.5 mA cm À2 at 0.6 V vs. RHE Bi 2 FeCrO 6 [169] pulsed laser deposition none 1 m Na 2 SO 4 À1.02 mA cm À2 at À0.97Vvs. RHE ChemSusChem 2017, 10,3001 -3018 www.chemsuschem.org ized the performances, issues, and challenges of bismuth-containing materials for PEC water splitting.…”

“…Apart from these transition-metaloxides, WO 3 and Fe 2 O 3 are commonly investigated as photoanodes, because they possess narrow band gaps and efficiently harvest sunlight. [33][34][35] It is noteworthy that the electronic structure of bismuth-based materials comprises the 6s orbital of Bi and the 2p orbitalo f oxygen in the valence band, whereas the valence band of other metal oxides, for instance, TiO 2 ,c onsists of the 2p orbital of oxygen only. Bismuth-based nanomaterials are promising candidates, as most them are visible-light responsivef or photoelectrocatalytic water splitting.…”

“…Bismuth-based nanomaterials are promising candidates, as most them are visible-light responsivef or photoelectrocatalytic water splitting. [33][34][35] It is noteworthy that the electronic structure of bismuth-based materials comprises the 6s orbital of Bi and the 2p orbitalo f oxygen in the valence band, whereas the valence band of other metal oxides, for instance, TiO 2 ,c onsists of the 2p orbital of oxygen only. [36,37] This important feature results in bismuth-In recent years, bismuth-based nanomaterials have drawn considerable interesta sp otentialc andidates for photoelectrochemical( PEC) water splitting owing to their narrow band gaps, nontoxicity,a nd low costs.…”

Foto(eletro)reforma do glicerol empregando filmes de Bi2WO6 como fotoanodos seletivos

“…Desse modo, obteve-se valores de bandgap de 2,8 eV (± 0,1) para as amostras sintetizadas em pH diferente de 2, de modo que as mesmas apresentam certa absorção na região visível do espectro. Os valores encontrados são, em geral, condizentes com os reportados na literatura, comumente entre 2,7 e 2.9 eV (TANG; ZOU; YE, 2004;SAISON et al, 2013;ZHANG, Y. et al, 2013;CHAE et al, 2014). Por outro lado, a amostra obtida em pH 2, apresentou um de bandgap de 3,2 eV, essa diferença pode ser explicada pelo menor tamanho de partícula do material, uma vez que o decréscimo no tamanho de partícula pode resultar no confinamento dos portadores de carga, o que resulta num aumento da energia de band gap (FERREIRA et al, 2017;GOYAL;DEVLAL, 2018).…”

“…Nessas condições é possível avaliar qual a amostra tem a melhores propriedades de superfície para promover processos de transferência eletrônica. Além disso, para aplicação fotoeletroquímica, é desejável que o material tenha a banda de condução mais negativa que o potencial de redução do H + , uma vez que isso confere um melhor acoplamento com o catodo, o que reduz o sobrepotencial elétrico requerido pela PEC (WEBER; DIGNAM, 1984;WALTER et al, 2010;CHAE et al, 2014).…”