A Simplified Successive Ionic Layer Adsorption and Reaction (s-SILAR) Method for Growth of Porous BiVO₄Thin Films for Photoelectrochemical Water Oxidation

Abstract

Since monoclinic bismuth vanadate (BiVO4) has been considered to be a promising anode material for photoelectrochemical (PEC) water splitting, the synthesis of high-quality BiVO4 photoanodes for use in PEC cells is beneficial. Here, we report a facile simplified successive ionic layer adsorption and reaction (s-SILAR) method to synthesize porous BiVO4 films. Evaluation of the porous BiVO4 film as a photoanode yielded photocurrents of ∼0.70 and ∼1.20 mA cm−2 at 1.23 V vs RHE under AM1.5G irradiation for water and sulfite oxidation, respectively. After coupling with a cobalt–phosphate (Co-Pi) catalyst, its photocurrent for water oxidation increased to ∼0.97 mA cm−2 at 1.23 V vs RHE. The high performance of the resultant BiVO4 films and simplicity of operation make this s-SILAR technique a promising strategy to prepare BiVO4 photoanodes.

Rational Design of Photoelectrodes for the Fully Integrated Polymer Electrode Membrane–Photoelectrochemical Water-Splitting System: A Case Study of Bismuth Vanadate

“…■ DEVELOPMENT OF BIVO 4 ON PEM−PEC SUITABLE SUBSTRATES BY S-SILAR In the literature, BiVO 4 thin films have been deposited by various methods including electrochemical deposition, 20,34 spin-coating, 35 reactive sputtering, 36 dip-coating, 37,38 and hydrothermal methods. 39 Out of these, electrochemical deposition of BiVO 4 on FTO-coated glass substrate has been the most successful with the highest current density and stability reported so far.…”

“…In the literature, BiVO 4 thin films have been deposited by various methods including electrochemical deposition, , spin-coating, reactive sputtering, dip-coating, , and hydrothermal methods . Out of these, electrochemical deposition of BiVO 4 on FTO-coated glass substrate has been the most successful with the highest current density and stability reported so far. , However, the electrochemical deposition method is sensitive to the electrolyte purity, environment, and applied bias.…”

“…Herein, we employ the cost-effective, scalable, and easy to use technique known as successive ionic layer adsorption and reaction (SILAR), which is the modified form of simple dip-coating for the preparation of a BiVO 4 thin film. , In particular, we use a simplified-SILAR (s-SILAR) method in which there are rinse steps (which are typical used in SILAR procedures) in the process of film preparation as shown in Scheme c. We replaced the conventional FTO-coated glass substrate with a porous conductive Ti-felt substrate to enable the photoanode for direct integration on the PEM–PEC reactor.…”

SILAR Deposition of Metal Oxide Nanostructured Films

“…The case of metal vanadates is a perfect example to elucidate this aspect. SILAR-based metal vanadates recently highlighted include Cu 2 V 2 O 7 , [168] Ag 3 VO 4 , [169] BiVO 4 , [170,171] and Fe 2 V 4 O 13 , [172] which have all been mostly employed as the light active materials for photoelectrochemical water splitting. Commonly in all of these, a soluble salt of the desired metal constitutes the cationic precursor while in most cases, ammonium or sodium vanadates were utilized as the vanadium precursor in the deposition process.…”

“…Due to the insolubility of Bi(NO 3 ) 3 in water, acid was added to the bismuth precursor to assist the dissolution. Guo et al [170] used acetic acid or acetic acid/water mixture as the solvent to prepare the Bi bath and SEM images revealed that the BiVO 4 film prepared via acetic acid was dense while it was much more porous if using mixture of water and acetic acid as the solvent for Bi(NO 3 ) 3 . BiVO 4 films prepared from different cycles were investigated in PEC performances and the optimized cycle was 20 and the best annealing temperature was 450 °C.…”