Search query: Photoelectrochemical oxidation of organic solution

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abstract: The development of ultra efficient, sustainable, and easily accessible anode with relative non precious semiconducting metal oxides is highly significant for application in the practical treatment of organically polluted water. Herein, we report SnO2, TiO2, and Ag2O ternary semiconductor metal oxide blend grafted Ag@AgCl hybrids, prepared with the one step sol gel method and applied as a dimensionally stable anode (DSA) active layer on a SnO2 Sb/Ti electrode. Factors affecting crystal formation, including the presence or absence of O2 during calcination, the calcination temperature, and Ag@AgCl additive dosage were discussed. The micromorphology, phase composition, and photoelectrochemical activity of the newly designed anode were comprehensively characterized. The optimized preparation, which yielded a solid solution structure with flat and smooth surface and well crystallized lattice configuration, occurred in the absence of O2 during calcination at 550 with an Ag@AgCl additive dosage of 0.2 g in the sol gel precursor. The newly designed DSA displayed improved electrocatalysis (EC) and photoelectrical catalysis (PEC) capacity. The phenol and its TOC removal efficiency reached 90.65% and 58.17% for 10 mA/cm2 current density with a metal halide lamp in 3 h. The lifespan was four times that of SnO2 Sb/Ti electrode. This proposed DSA construction strategy may support improved EC and PEC reactivities toward the decomposition of organic pollutants.
author_names: Peng Li

Zhenan Bao

Guanghui Wang

Pengfei Xu

Xue-Gang Wang

Zhipeng Liu

Yadan Guo

Jing Deng

Weimin Zhang
title: Ternary semiconductor metal oxide blends grafted Ag@AgCl hybrid as dimensionally stable anode active layer for photoelectrochemical oxidation of organic compounds: Design strategies and photoelectric synergistic mechanism.
venue: Journal of hazardous materials
year: 2019

abstract: This study investigated the influence of adding peroxydisulfate (PDS) to a photoelectrocatalysis (PEC) system using self doped TiO2 nanotube arrays (bl TNAs) for organic pollutant degradation. The addition of 1.0 mM PDS increased the bisphenol A (BPA) removal efficiency of PEC (PEC/PDS) from 65.0% to 85.9% within 1 h. The enhancement could be attributed to the high formation yield of hydroxyl radicals *OH) increased charge separation, and assistance of the sulfate radicals (SO4* The PDS concentration and applied potential bias were influential operating parameters for the PEC/PDS system. In addition, the system exhibited a highly stable performance over a wide range of pH values and background inorganic and organic constituents, such as chloride ions, bicarbonate, and humic acid. Further, the degradation performance of the organic pollutant mixture, including BPA, 4 chlorophenol (4 CP) sulfamethoxazole (SMX) and carbamazepine (CBZ) was evaluated in 0.1 M (NH4)2SO4 solution and real surface water. The degradation efficiency increased in the order of CBZ SMX 4 CP BPA in the PEC and PEC/PDS systems with both water matrices. Compared with the PEC system, the PEC/PDS (1.0 mM) system showed a threefold higher pseudo first order reaction rate constant for BPA among pollutant mixtures in surface water. This was attributed to enhanced *OH production and the selective nature of SO4* The pseudo first order reaction rate constants of other pollutants, i.e. 4 CP, SMX, and CBZ increased ca. twofold in the PEC/PDS system. The results of this study showed that the PEC/PDS system with bl TNAs is a viable technology for oxidative treatment.
author_names: Aseom Son

Jiho Lee

Changha Lee

Kangwoo Cho

Jaesang Lee

Seok Won Hong
title: Persulfate enhanced photoelectrochemical oxidation of organic pollutants using self doped TiO2nanotube arrays: Effect of operating parameters and water matrix.
venue: Water research
year: 2021

abstract: Organic metal halide perovskite material has attracted intense interest in the photovoltaic field due to its excellent optoelectronic properties, but the extreme susceptibility of organolead halide perovskite to water seriously impedes its application for photoelectrochemical (PEC) conversions in aqueous solution. In this work, we develop an organolead halide perovskite photoanode of conventional electrode structure. The perovskite photoanode was fabricated by using a facile approach and encapsulated with conductive carbon paste and silver conductive paint for waterproof function, and the PEC water splitting was carried out as a model of PEC conversion. For PEC water oxidation, the photoanode achieved a remarkable photocurrent density of 12.4 mA/cm2 at 1.23 V versus reversible hydrogen electrode in alkaline electrolyte. In addition, the as prepared photoanode of conventional structure exhibited an unprecedented stability, which could be stable in alkaline electrolyte for more than 48 h. More importantly,
author_names: Ran Tao

Zhixia Sun

Fengyan Li

Wencheng Fang

Lin Xu
title: Achieving Organic Metal Halide Perovskite into a Conventional Photoelectrode: Outstanding Stability in Aqueous Solution and High Efficient Photoelectrochemical Water Splitting
venue: ACS Applied Energy Materials
year: 2019

abstract: Solution processable organic semiconductors have potentials as visible photoelectrochemical (PEC) water splitting photoelectrodes due to their tunable small band gap and electronic energy levels, but they are typically limited by poor stability and photocatalytic activity. Here, we demonstrate the direct visible PEC water oxidation on solution processed organic semiconductor thin films with improved stability and performance by ultrathin metal oxide passivation layers. N type fullerene derivative thin films passivated by sub 2 nm ZnO via atomic layer deposition enabled the visible PEC water oxidation at wavelengths longer than 600 nm in harsh alkaline electrolyte environments with up to 30 mA/cm2 photocurrents at the thermodynamic water oxidation equilibrium potential and the photoanode half lifetime extended to ~1000 s. The systematic investigation reveals the enhanced water oxidation catalytic activity afforded by ZnO passivation and the charge tunneling governing the hole transfer through passivation l.
author_names: L Wang

Danhua Yan

David W Shaffer

Xinyi Ye

Bobby Layne

Javier J Concepcion

Mingzhao Liu

Chang-Yong Nam
title: Improved Stability and Performance of Visible Photoelectrochemical Water Splitting on Solution Processed Organic Semiconductor Thin Films by Ultrathin Metal Oxide Passivation
year: 2018

abstract: Abstract Metal organic frameworks (MOFs) are promising co catalysts for increasingenhancing the performance of photoelectrochemical (PEC) water splitting. In this work, we successfully fabricated an efficient BiVO4 photoanode for PEC water oxidation by decorating its surface with Bi based MOF as a co catalyst via an unconventional immersion process at an ambient temperature. Bi MOF exhibits a large surface area and promotes bulk charge separation and surface charge transfer in the water oxidation reaction, resulting in an enhancement in the photocurrent density, which is approximately two times larger than that of the bare BiVO4 photoanode. In addition, the operation stability of our Bi MOF/BiVO4 photoanode was dramatically improved, and more than 95% of its initial photocurrent density was retained even after 24 h, indicating that the improved charge transfer by the Bi MOF layer prohibits the dissolution of the BiVO4 layer into the solution during the water oxidation reaction.
author_names: Seungkyu Kim

Top Archie Dela Pena

Sehun Seo

Jun-cheol Park

Jong-Hoon Lee

Jae Ha Woo

Chang Hyuck Choi
title: Co catalytic effects of Bi based metal organic framework on BiVO4 photoanodes for photoelectrochemical water oxidation
year: 2021

abstract: Abstract The degradation of pollutants with the simultaneous promotion of hydrogen production is an attractive and promising solution for the current environmental and energy problem, but few studies have been performed concerning the trends and mechanism of this process. Two classes of typical pollutants, phenols and alkylbenzenes, are treated using a self biasing photoelectrochemical (PEC) cell to reveal the intrinsic relationships between the redox properties of the pollutants and hydrogen production. The results show that the TOC removal rates of these pollutants range from 63.5% to 93.6% The highest hydrogen production efficiency (e H2 which is the ratio of experimental and theoretical hydrogen production amounts, reaches 81.5% The degradation rate constant (k) decreases as the experimental photoelectrocatalytic oxidation potential (E PEC increases. This trend can be explained by the degradation pathway deduced from the detection of intermediate products using LC MS and the associated reaction energetics from theoretical calculations. Neither the degradation rate constant (k) nor the TOC removal amounts (DTOC) determines the hydrogen production. The e H2 value positively depends on the average oxidation current efficiency (ACE) which is the ratio of experimental to theoretical TOC removal amounts. This study reveals a significant theory for the use of wastewater for hydrogen production.
author_names: Zhongyi Wu

Zhaoyu Zhou

Yajun Zhang

Jie Wang

Huijie Shi

Qi Shen

Guangfeng Wei

Guohua Zhao
title: Simultaneous photoelectrocatalytic aromatic organic pollutants oxidation for hydrogen production promotion with a self biasing photoelectrochemical cell
year: 2017

abstract: Abstract Morphology engineering is of prime significance in designing semiconductor photoelectrodes for efficient photoelectrochemical (PEC) fuel generation. Herein, we report a strategy to fabricate nanostructured tungsten oxide films using anodic oxidation of tungsten and their performance as photoanodes for PEC water splitting. A solution of an organic compound, dimethyl sulfoxide, with hydrofluoric acid was used as the electrolyte. The anodization parameters such as voltage and electrolyte temperature were found to have a critical influence in determining the porous nature and dimensions of the resulting oxide film. Anodization conducted at a voltage ~10 V and a temperature ~40 degC led to the formation of compact tungsten oxide films due to the low strength of the electric field partially responsible for the porous morphology development. The surface of the film became porous at elevated temperatures. At higher voltages, a thin nanoporous film atop a thicker compact layer was formed; however, the structure became more disordered and less porous when the electrolyte temperature was increased. The study demonstrated that by adjusting the voltage and temperature, the oxide film morphology could be varied from a compact layer to a porous structure resembling nanotubes. The films heat treated at 500 degC attained the monoclinic phase of WO3. The PEC performance was influenced strongly by the morphology of the films. The films with nanotube like morphology yielded incident photon to current conversion efficiency values of over 40% This study would provide a practical basis for developing optimal WO3 nanostructures for efficient PEC fuel generation.
author_names: Tao Zhang

Maggie Paulose

Ram P Neupane

Lillian Aurora Schaffer

Dhan Bahadur Rana

Jinzhan Su

Liejin Guo

Oomman K Varghese
title: Nanoporous WO3 films synthesized by tuning anodization conditions for photoelectrochemical water oxidation
year: 2020

abstract: Methanol is an available, small, and colorless molecule, which can be used for the photocatalytic activity evaluation without the sensitization problem associated with most dye molecules. Thus, TiO2 suspended in aqueous methanol solutions is commonly employed as a model test for the photocatalytic degradation of organic pollutants in aerobic system or for photocatalytic hydrogen production in absence of molecular oxygen. It is, hence, important to explore the mechanism of its photocatalytic and photoelectrochemical oxidation on TiO2 in aqueous solution. In this mini review, the possible mechanisms for water and methanol oxidation on TiO2 will therefore be presented and discussed.
author_names: Amira Y Ahmed

Tarek A Kandiel

Irina I Ivanova

Detlef W Bahnemann
title: Photocatalytic and photoelectrochemical oxidation mechanisms of methanol on TiO2 in aqueous solution
year: 2014

abstract: Abstract In this study, the organic solvent free 'green synthesis' of bismuth vanadate (BiVO 4 has been described for its application in photoelectrochemical (PEC) water oxidation. BiVO 4 thin films were successfully prepared through electrodeposition of Bi film on the FTO glass substrate from the aqueous bath containing Bi(NO 3 3 in presence of K Na tartrate and dextrose; followed by thermo chemical reaction with an aqueous solution of vanadium acetylacetonate (VO(acac) 2 XRD SEM EDS analyses indicated the formation of scheelite monoclinic BiVO 4 with seed like morphology. UV visible absorption spectra measured the band gap energy 2.3 eV indicating visible light activity of the photocatalyst and the Mott Schottky analysis showed n type nature of the semiconductor. Highest photocurrent of 1.3 mA cm 2 (at ~1 V vs Ag/AgCl) for water oxidation and 2 mA cm 2 (at ~0.6 V vs Ag/AgCl) for sacrificial (SO 3 2 oxidation were measured under 35 mW cm 2 illumination using the optimized thin film and the maximum incident photon to current conversion efficiency (IPCE) of 42% was obtained. The enhanced photocurrent in solar assisted water oxidation is attributed to the formation of well covered and compact film with improved electrical continuity, shown by minimum charge transfer resistance. Adsorption of an optimized amount of Co 2+ over the BiVO 4 improves its catalytic properties towards oxygen evolution reaction by approximately 2.5 times, with lowering of charge transfer resistance of the material as measured through impedance analysis.
author_names: P K Hajra

Sukumar Kundu

Arjun Maity

Chinmoy Bhattacharya
title: Facile photoelectrochemical water oxidation on Co2+ adsorbed BiVO4 thin films synthesized from aqueous solutions
venue: Chemical Engineering Journal
year: 2019

abstract: Coupling semiconducting metal organic frameworks (MOFs) with metal oxide (MO) semiconductor nanowires is an efficient solution to tune the photoelectric properties of both the parties. In this report, we demonstrate a facile surfactant free growth strategy for modification of zinc oxide (ZnO) single crystal nanowire arrays (NWAs) with the MOF zinc glycolate (noted as Zn GA) that contains an embedded continuous 3D Zn O network. Due to the structural resemblance of the Zn O network between Zn GA and ZnO, the prepared ZnO@Zn GA nanowires present a tight contact at the core shell interface in a partially epitaxial manner, and the loading amount of Zn GA can be well controlled in the synthetic process. The inherent p type Zn GA in combination with the widely available n type ZnO assures the construction of tandem n p heterojunctions at the core shell interface, which is confirmed by Mott Schottky analysis. By implementation of the ZnO@Zn GA NWAs as photoanodes for photoelectrochemical oxidation of water and oxalic acid, improved photocurrent responses are obtained relative to the primary ZnO NWAs. The most significant photoresponse is observed in the ZnO nanowires shelled by a compact Zn GA particulate thin film with the largest junction region. These results are elucidated by the enhanced spatial separation efficiency of photogenerated charge carriers, which is favored by the built in electric field at the interface of the n p heterojunctions.
author_names: Qianqian Gao

Huihui Kang

Yun Cai

Daxiang Xue

Fengjiao Yu

Jun Fang

Yang Yang
title: Improving photoelectrochemical response of ZnO nanowire arrays by coating with p type ZnO resembling metal organic framework.
venue: Dalton transactions
year: 2019