High Water Oxidation Performance of W‐Doped BiVO₄ Photoanodes Coupled to V₂O₅ Rods as a Photoabsorber and Hole Carrier

Abstract

Monoclinic BiVO 4 is recognized as a promising photoanode for water oxidation, but its relatively wide bandgap energy (E g %2.5 eV) and poor charge transport limit the light absorption (η abs ) and charge separation (η sep ) efficiencies, thus resulting in low photocurrents. To solve these drawbacks, here the η abs  η sep product has been decoupled by combining W-doped BiVO 4 and V 2 O 5 rods (E g %2.1 eV) for simultaneously increasing the light harvesting and the charge separation in photoanodes under back-side illumination. In this strategy, V 2 O 5 rods maximize the light absorption and hole transport throughout the W-BiVO 4 film, making more holes to achieve the V 2 O 5 /W-BiVO 4 /H 2 O interface to trigger the water oxidation reaction with photocurrents as high as 6.6 mA cm À2 at 1.23 V RHE after 2 h reaction. Notably, under back-side illumination, the W-BiVO 4 /V 2 O 5 photoanode exhibited η abs  η sep of 74.5 and 93.0% at 0.5 and 1.23 V RHE , respectively, the highest values reported up to date for BiVO 4 -based photoelectrodes. This simple strategy brings us closer to develop efficient photoanodes for photoelectrochemical water splitting devices.

Pulsed Laser Deposition of Bismuth Vanadate Thin Films—The Effect of Oxygen Pressure on the Morphology, Composition, and Photoelectrochemical Performance

“…The lowest photoactivity was observed for samples deposited under 0.1 mbar. Generally, the formation of BiVO 4 /V 2 O 5 heterojunction can enhance the efficiency of photocurrent generation for both, layered and bulk types of junctions [10]. However, the geometry of the system significantly affects its photoactivity [33] due to the relative positions of conduction bands [34].…”

“…The most common ways consists of Mo and W doping [7] and heterostructures formation [8]. Up to now, the highest photocurrent densities were achieved for bulk (i) W-doped BiVO 4 /V 2 O 5 heterojunction (6.6 mA cm −2 ) and (ii) electrode material that was prepared on a scaffold of polystyrene spheres scaffold and consisted of WO 3 and molybdenum doped BiVO 4 nanoparticles (5.8 mA cm −2 ), both covered by a FeOOH/NiOOH dual layer catalyst [9,10]. However, the theoretical value of the photocurrent should be possible to achieve for "bare" BiVO 4 .…”

Studies of Graphdiyne‐ZnO Nanocomposite Material and Application in Polymer Solar Cells

“…To analyze the interfacial properties of PSCs devices, electrochemical impedance spectroscopy (EIS) measurement was performed at 0.7 V bias voltages under dark condition . The EIS results are shown in Figure (g).…”

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

“…The V 2 O 5 presence positively affects charge separation efficiency and light absorption ability due to the narrower energy bandgap. BiVO 4 was additionally doped using W atoms, and it leads to one of the highest photocurrents of water oxidation obtained for BiVO 4 -based photoanodes [15]. Other authors claim that the presence of V 2 O 5 in BiVO 4 /V 2 O 5 junction enhances mobility of charge carriers measured as transit time for the migration of photoexcited electrons to counter electrode, what was confirmed using intensity-modulated photocurrent spectroscopy [16].…”

“…Recently, BiVO 4 /V 2 O 5 junction has been characterized as a promising photoanode for water splitting. The various geometries of the junction (e.g., bulk, layer on layer) have been studied [15]. The V 2 O 5 presence positively affects charge separation efficiency and light absorption ability due to the narrower energy bandgap.…”