Enhanced Photoelectrocatalytical Performance of Inorganic-Inorganic Hybrid Consisting BiVO4, V2O5, and Cobalt Hexacyanocobaltate as a Perspective Photoanode for Water Splitting

Abstract

Thin layers of BiVO 4 /V 2 O 5 were prepared on FTO substrates using pulsed laser deposition technique. The method of cobalt hexacyanocobaltate (Cohcc) synthesis on the BiVO 4 /V 2 O 5 photoanodes consists of cobalt deposition followed by electrochemical oxidation of metallic Co in K 3 [Co(CN) 6 ] aqueous electrolyte. The modified electrodes were tested as photoanodes for water oxidation under simulated sunlight irradiation. Deposited films were characterized using UV-Vis spectroscopy, Raman spectroscopy, and scanning electron microscopy. Since the V 2 O 5 is characterized by a narrower energy bandgap than BiVO 4 , the presence of V 2 O 5 shifts absorption edge (ΔE =~0.25 eV) of modified films towards lower energies enabling the conversion of a wider range of solar radiation. The formation of heterojunction increases photocurrent of water oxidation measured at 1.2 V vs Ag/ AgCl (3 M KCl) to over 1 mA cm-2 , while bare BiVO 4 and V 2 O 5 exhibit 0.37 and 0.08 mA cm-2 , respectively. On the other hand, the modification of obtained layers with Cohcc shifts onset potential of photocurrent generation into a cathodic direction. As a result, the photocurrent enhancement at a wide range of applied potential was achieved.

BiVO4 Heterojunctions as Efficient Photoanodes for Photoelectrochemical Water Oxidation

“…Recently, some classical oxide semiconductor materials strive to be novel in constructing Type II heterojunction. such as WO 3 , MoO 3 , V 2 O 5 [6–9] Khan et al. first fabricated a WO 3 /BiVO 4 heterojunction photoanode with a conformal TiO 2 protective layer by a combination of hydrothermal and solution drop‐casting methods, as shown in Figure 3(a–d).…”

Controllable synthesis of nanostructured bismuth vanadate thin films as an efficient catalyst for photoelectrochemical water splitting

“…5(b), the photostability test of DI + EG showed B33.6% loss of photoanodic behavior over a period of 2500 s. The two sets of films are, therefore, separated by both their characteristics and photoelectrochemical performance. Since V 2 O 5 usually shows low photoelectrochemical performance and the presence of a negligible amount of V 2 O 5 could not form the potential BiVO 4 /V 2 O 5 heterojunction system to enhance charge separation, [55][56][57][58] high photocurrent in EtOH + HNO 3 and DI + EG is most likely caused by their morphologies and exposed facets. Here, the plate-like particles generally result in better PEC properties compared with the cuboid-like particles.…”

How to Build Prussian Blue Based Water Oxidation Catalytic Assemblies: Common Trends and Strategies

“…Both CoCo and CoFe PBAs enhance the photocurrent densities when they are coupled to BiVO 4 . [63][64][65] Transient absorption measurements reveal that a PBA coating enhances the performance by presenting a favorable interface for efficient hole transfer, thereby retarding recombination in the semiconductor, combined with the catalytic function necessary to drive water oxidation. [62] Pires et al also examined the use of cobalt pentacyanoferrate derivatives with different auxiliary ligands (CoFe-L; L = CN, NH 3 , isn, and mpz) on PEC performances of BiVO 4 photoanodes and investigated the effect of the ligand on the relative alignments of the band edges.…”

“…BiVO 4 , on the other hand, inherently has a proper band energy alignment among the recently employed SCs in this field. Both CoCo and CoFe PBAs enhance the photocurrent densities when they are coupled to BiVO 4 [63–65] . Transient absorption measurements reveal that a PBA coating enhances the performance by presenting a favorable interface for efficient hole transfer, thereby retarding recombination in the semiconductor, combined with the catalytic function necessary to drive water oxidation [62] …”