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Abstract: Transformation of biomass into value-added chemicals and fuels is considered an upcycling process that is beneficial to resource utilization. In this study, we used a photoelectrochemical (PEC) approach for selective oxidation of propane-1,2,3-triol to dihydroxyacetone (DHA) with high efficiency and selectivity (99%) using Sn-doped -Fe2O3 (Sn:-Fe2O3) thin films with intrinsic oxygen vacancies (OVs). DHA is an essential compound utilized in the cosmetic industry. In a similar manner, we conducted the first study of the PEC oxidation of 4-hydroxy-3-methoxybenzyl alcohol under visible light. A kinetic model has been formulated and solved to find the time-dependent generation of the products. Electrochemical impedance analyses and PEC experiments demonstrated a correlation between the concentration of molecules and the catalytic performance of Sn:-Fe2O3. Studies using scavengers indicate that the photogenerated holes (h+), singlet oxygen (1O2), hydroxyl radicals (•OH), and superoxide radicals (•O2–) play key roles in achieving high PEC activity. This work provided a new perspective on designing efficient PEC systems for biomass conversion into energy and value-added chemicals.
Keywords: Sn-doped alpha-Fe2O3, oxygen vacancies, photoelectrochemical oxidation, propane-1, 2, 3-triol, 4-hydroxy-3-methoxybenzyl alcohol
Published in RUNG: 08.01.2025; Views: 708; Downloads: 6
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Abstract: Introduction of oxygen vacancies (OVs) has been investigated as a promising way to improve the electrical and catalytic characteristics of a hematite (α-Fe2O3) based photoelectrode. In this work, we develop a novel method for preparing porous Sn-doped α-Fe2O3 (Sn:Fe2O3) thin films with intrinsic OVs. The procedure included spin- coating an iron precursor onto a fluorine-doped tin oxide (FTO) substrate, followed by thermal treatment at elevated temperatures. The influence of Sn dopant on the optoelectronic properties of α-Fe2O3 was demonstrated by X-ray photoelectron spectroscopy and photoelectrochemical (PEC) measurements. The combined effect of OVs and Sn doping was found to play a synergistic role in reducing the charge recombination’s. The Sn:Fe2O3 photoanodes were used as a dual catalyst to oxidise water and break down an anti-inflammatory drug called 2-(4- isobutylphenyl)propanoic acid (IBPA). The Sn:Fe2O3 thin film with a 30-minute heat treatment time displayed the highest incident photon-to-current efficiency. For the first time, Sn:Fe2O3 thin films were utilised in the effective PEC degradation of IBPA employing peroxymonosulfate (PMS) under visible light illumination. The hydroxyl radicals (•OH), singlet oxygen (1O2), photogenerated holes (h+), and sulfate radicals (SO4 • ) were discovered to be the main reactive species during PEC degradation. IBPA degradation and the formation of new compounds were verified using liquid chromatography-mass spectrometry. The Lepidium sativum L phytotoxicity test reveals that PEC-treated wastewater with IBPA exhibits decreased toxicity.
Keywords: Sn-doped Fe2O3, oxygen vacancies, photoelectrochemical degradation, 2-(4-isobutylphenyl)propanoic acid, peroxymonosulfate
Published in RUNG: 10.01.2024; Views: 2259; Downloads: 42
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