Cold sprayed WO₃and TiO₂electrodes for photoelectrochemical water and methanol oxidation in renewable energy applications

Abstract

Films prepared by cold spray have potential applications as photoanodes in electrochemical water splitting and waste water purification. In the present study cold sprayed photoelectrodes produced with WO 3 (active under visible light illumination) and TiO 2 (active under UV illumination) on titanium metal substrates were investigated as photoanodes for the oxidation of water and methanol, respectively. Methanol was chosen as organic model pollutant in acidic electrolytes. Main advantages of the cold sprayed photoelectrodes are the improved metal-semiconductor junctions and the superior mechanical stability.Additionally, the cold spray method can be utilized as a large-scale electrode fabrication technique for photoelectrochemical applications. Incident photon to current efficiencies reveal that cold sprayed TiO 2 / WO 3 photoanodes exhibit the best photoelectrochemical properties with regard to the water and methanol oxidation reactions in comparison with the benchmark photocatalyst Aeroxide TiO 2 P25 due to more efficient harvesting of the total solar light irradiation related to their smaller band gap energies.

Jet nebulizer-spray coated CZTS film as Pt-free electrocatalyst in photoelectrocatalytic fuel cells

“…The crystalline growth of CZTS by JNS spray coating rely on surface mobility of the atomic species on the substrate and intake metal precursor composition, which further control by substrate temperature.For instance, the CZTS coating at higher temperature (350 C) results high crystalline intensity peak along (112) c-axis ensure the temperature effect on crystal growth. The plausible reason for predominant crystal growth along (112) plane may due to the Cu enriched defect sites[7] and is in line with previous reports on spray coating[1,2,5] as well as other techniques[4,6]. The average crystalline size of CZTS films found to be increased from 24 nm to 57 nm by increasing processing temperature from 250 to 350 C. We experienced that the CZTS films were feel-off from the substrate while prepared below 250 C. Therefore, a minimum thermal energy is required for good CZTS film formation.The degree of preferred orientation of the different crystalline planes at different processing temperatures were analysed through evaluating texture coefficient (TC) using the Harris analysis[39] k, and l are the Miller indices; TC(hkl) is the texture coefficient value of specific (hkl) planes; I(hkl) is the measured peak intensity; and ΣI(hkl) is the summation of the intensities for the (112), (220) and (312) peaks of the CZTS films.The estimated TC values for different crystalline plane were presented inFigure 1 (b).…”

“…The photoelectrochemical (PEC) technique is a promising tool in energy generation [1] and offers flexible choice of electrolyte feed stock including sea water, industrial pollutant, and non-aqueous chemicals [2][3][4][5] . This facilitate to apply PEC in wide range of commodity valuable applications including cheap fuel generation (oxygen, and hydrogen), chemical synthesis, water treatment and value added to other applications [6].…”

Tailoring the Photoelectrochemical Activity of TiO2 Electrodes by Multilayer Screen‐Printing

“…Even if the parent material is the same, the chosen method will considerably impact the photoactivity of the resulting films . A particularly useful procedure is the screen‐printing technique, since it is fast, reproducible, and inexpensive, which makes it ideal for large‐scale fabrication . For this method a paste is prepared out of the photocatalyst powder and deposited through the mesh of a screen on an adequate substrate, and after a calcination step the electrode is obtained.…”

Systematic Material Study Reveals TiNb2O7 as a Model Wide‐Bandgap Photoanode Material for Solar Water Splitting

“…In contrast to the films, photocharacterization of our (minimally loaded) powder‐based TNO photoanode revealed promising kinetic features: the sharp photocurrent onset potential near 0.4 V versus RHE rivals or exceeds that of state‐of‐the‐art photoanode materials . The sharp nature of the photocurrent (red curve in Figure a) at the onset photovoltage also implies that photochemical reactions likely show quasi‐ideal kinetic behavior.…”