Cooperative Catalytic Effect of ZrO₂ and α‐Fe₂O₃ Nanoparticles on BiVO₄ Photoanodes for Enhanced Photoelectrochemical Water Splitting

Abstract

Photoelectrochemical water splitting with metal oxide semiconductors offers a cost-competitive alternative for the generation of solar fuels. Most of the materials studied so far suffer from poor charge-transfer kinetics at the semiconductor/liquid interface, making compulsory the use of catalytic layers to overcome the large overpotentials required for the water oxidation reaction. Herein, we report a very soft electrolytic synthesis deposition method, which allows remarkably enhanced water oxidation kinetics of BiVO photoanodes by the sequential addition of Zr and Fe precursors. Upon a heat treatment cycle, these precursors are converted into monoclinic ZrO and α-Fe O nanoparticles, which mainly act as catalysts, leading to a five-fold increase of the water oxidation photocurrent of BiVO . This method provides a versatile platform that is easy to apply to different semiconductor materials, fully reproducible, and facile to scale-up on large area conductive substrates with attractive implications for technological deployment.

Semiconductor α‐Fe2O3 Hematite Fabricated Electrode for Sensitive Detection of Phenolic Pollutants

“…XRD diffraction pattern of the sample shown in Figure b shows the characteristic peaks of hematite phase (α‐Fe 2 O 3 ) crystals, together with FTO peaks from the substrate which are labeled with an asterisk, confirming the formation of hematite after electrodeposition . The electrode shows to be very active for the oxidation of water under basic conditions (1 M KOH) as reported previously (see Figure SI1) . Films are relatively flat with some texture that provides photocurrent of oxygen evolution under illumination conditions of 300 μA/cm 2 at 0.4 V vs Ag/AgCl.…”

Level Alignment as Descriptor for Semiconductor/Catalyst Systems in Water Splitting: The Case of Hematite/Cobalt Hexacyanoferrate Photoanodes

“…Thin‐film hematite electrodes were prepared by a simple and cost‐efficient electrodeposition method, based on a description by Shaddad et al., but with varying calcination conditions as in Refs. .…”

An integrated photoanode based on non-critical raw materials for robust solar water splitting

“…We previously showed that electrochemical deposition of Fe under specific conditions led to the formation of catalytically active a-Fe 2 O 3 nanoparticles on the surface of a water splitting photoanode. 38 Although a-Fe 2 O 3 has been widely studied as a water oxidation photoanode, [39][40][41][42][43] it has been suggested that electrodeposited a-Fe 2 O 3 particles provide cooperative electrocatalytic behavior on BiVO 4 photoanodes for water oxidation. 38 Three different deposition charges of Fe were tested: 5, 12 and 25 mC cm À2 , corresponding to 0.49, 1.06 and 6.27 at% of Fe detected by EDS analysis on Ni foil (ESI, † Fig.…”