Preparation of Nanoparticle Porous-Structured BiVO4 Photoanodes by a New Two-Step Electrochemical Deposition Method for Water Splitting

Abstract

In the synthesis method of a BiVO4 photoanode via BiOI flakes, a BiOI film is formed by electrochemical deposition in Step 1, and a vanadium (V) source solution is placed by drop-casting on the BiOI film in Step 2. Following this, BiVO4 particles are converted from the BiOI–(V species) precursors by annealing. However, it is challenging to evenly distribute vanadium species among the BiOI flakes. As a result, the conversion reaction to form BiVO4 does not proceed simultaneously and uniformly. To address this limitation, in Step 2, we developed a new electrochemical deposition method that allowed the even distribution of V2O5 among Bi–O–I flakes to enhance the conversion reaction uniformly. Furthermore, when lactic acid was added to the electrodeposition bath solution, BiVO4 crystals with an increased (040) peak intensity of the X-ray diffractometer (XRD) pattern were obtained. The photocurrent of the BiVO4 photoanode was 2.2 mA/cm2 at 1.23 V vs. reversible hydrogen electrode (RHE) under solar simulated light of 100 mW/cm2 illumination. The Faradaic efficiency of oxygen evolution was close to 100%. In addition, overall water splitting was performed using a Ru/SrTiO3:Rh–BiVO4 photocatalyst sheet prepared by the BiVO4 synthesis method. The corresponding hydrogen and oxygen were produced in a 2:1 stoichiometric ratio under visible light irradiation.

Development and Functionalization of Visible-Light-Driven Water-Splitting Photocatalysts

“…In addition to producing energy in combustion engines, H 2 can also be directly converted into electric power by fuel cells ( Figure 1 A). If H 2 can be produced via a photocatalytic water-splitting reaction [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ], renewable energy can be produced from sunlight and water, which are abundant on Earth ( Figure 1 B). Therefore, water-splitting photocatalysts have attracted huge attention as a means to address energy and environmental problems.…”

Experimental Evidence for Photoactivated BiVO4 Anodes with Enhanced Photoelectrochemical Water Oxidation

“…BiVO 4 photoanodes were fabricated using our original method. 32 In step 1, a 30 mL electrodeposition bath was prepared by combining an aqueous solution containing 0.0075 mol L −1 bismuth(III) nitrate pentahydrate [Bi-(NO 3 ) 3 •5H 2 O, 98%, Alfa Aesar], 0.4 mol L −1 potassium iodide (KI, Tianjin Zhiyuan Reagent Co., Ltd.), and 60 mmol L −1 lactic acid (C 3 H 6 O 3 , 85%, Acros Organics). The pH of the solution was adjusted to 1.0−1.2 using nitric acid (HNO 3 , Guangzhou Chemical Reagent).…”

Scaling up BiVO4 Photoanodes on Porous Ti Transport Layers for Solar Hydrogen Production

“…The authors have cited additional references within the Supporting Information. [19][20][21][40][41][42]50,53,54,[58][59][60][61][62]…”

“…Supporting information for this article is available on the www under https://doi.org/10.1002/cssc.300969. The authors have cited additional references within the Supporting Information [19–21,40–42,50,53,54,58–62] …”