FeOOH Species Research Articles

Defect-rich CoFeCu alloy nanoflowers for efficient oxygen evolution reaction in alkaline media

Energy shortages and environmental problems caused by the intensive use of fossil fuels have led to an urgent search for alternative energy sources. The solar-powered hydrogen generation from water splitting is expected to replace the traditional fossil fuels extraction. However, the slow anodic oxygen evolution reaction (OER) of the water splitting limits the overall efficiency of hydrogen production. The introduction of foreign atoms into bimetallic alloys is an effective strategy for constructing rich defects, modulating the electronic structure and optimizing the electrocatalytic performance. In this study, CoFeCu alloy nanoflowers (CoFeCu/NF) are prepared as electrocatalysts for OER by introducing Cu into the CoFe alloy through a facile electrodeposition method. It is revealed that the introduction of Cu not only enhances the electronic interactions between the elements, i.e., Co, Fe, and Cu, but also induces the generation of a large number of Fe3+ cationic vacancies which facilitate the surface reconstruction of Fe into FeOOH species during OER. Benefiting from the synergistic effect of CoOOH and FeOOH generated by in-situ electrochemical reconstruction, CoFeCu/NF exhibits satisfactory OER catalytic performance in 1.0 M KOH (η10 mA cm−2 = 257 mV) and is able to maintain a good stability for 48 h at 50 mA cm−2. Our work demonstrates the roles of introducing Cu into transition metal-based alloys and provides an effective strategy for the rational design of OER electrocatalysts in alkaline media.

Unraveling the Evolution of Dynamic Active Sites of LaNixFe1-xO3 Catalysts During OER.

Perovskites have attracted tremendous attention as potential catalysts for the oxygen evolution reaction (OER). It is well-known that the introduction of Fe into rare earth perovskites such as LaNiO3 enhances the intrinsic OER activity. Despite numerous studies on structure-property relationships, the origin of the activity and the nature of the active species are still elusive and unclear. In this work, we study a series of LaNixFe1-xO3 perovskites using in situ electrochemical surface-enhanced Raman spectroscopy and electron energy loss spectroscopy to decipher the surface evolution and formation of active species during OER. While the origin of the activity arises from NiOOH species formed from the active Ni centers in LaNiO3, our work shows that Fe serves as the active center in LaNi0.5Fe0.5O3 and forms Fe-O-Ni and FeOOH species during OER. The OER activity of LaFeO3 originates from FeOOH species, which interact with the soluble Ni species in the electrolyte forming an active electrode-electrolyte interface with high-valent stable surface iron species (Fe4+) and thereby improving the performance. Our work provides deeper insights into the synergistic effects of Ni and Fe on the catalytic activity, which in turn provides new design principles for perovskite catalysts for the OER.

Enhancing Oxygen Evolution Reaction through In Situ Electrochemical Oxidation for the Structural Control of Co-Fe Prussian Blue Analogue

The development of exceptionally efficient catalysts for the oxygen evolution reaction (OER) and gaining a deep understanding of their activity is essential for advancing electrochemical conversion technologies. Prussian blue analogues (PBAs) serve as promising pre-catalysts for the OER. However, PBAs, typically prepared through the conventional co-precipitation method, exhibit a lower active site density and limited electrical transport, making them suitable precursors for the derivation of PBA derivatives. In this research, we identified a significant enhancement in the electrocatalytic performance of Co-Fe Prussian blue analogue (CoFe PBA) through electrochemical oxidation. The cubic CoFe PBA was synthesized by one-step co-precipitation method using adjusting the amount of sodium citrate and potassium ferricyanide. After the electrochemical treatment, CoFe PBA demonstrates remarkable attributes, including a low overpotential of 331mV at a current density of 10mA·cm-2, a small Tafel slope of 50.4mV·dec-1, and excellent long-term stability during electrolysis in a 1M KOH alkaline medium for over 37h. Moreover, the electrochemical oxidation of CoFe PBA was comprehensive, employing techniques such as Transmission electron microscope, Powder X-ray diffraction, and X-ray photoelectron spectroscopy. These analyses confirmed the presence of real active substances, including CoOOH and a part of FeOOH species, further supporting the observed improvements in electrocatalytic activity.

Evaluation of iron containing biochar composites prepared by different preparation methods for H2O2 sensing

BackgroundThe procedures employed to prepare the ferrous biochar samples, the iron salts utilized, and their quantities have an effect on the surface characteristics of the material and the types of iron that will develop on the surface. MethodsIron containing biochar (Fe-BC) samples were prepared using three different preparation methods: Precipitation, Impregnation (IP) and Solid-state (SS). The iron content of the biochar (BC) was varied in a range from 6.5 to 21.0 wt. % by using a SS method that mechanically mixed FeCl3 and hazelnut shell (HS) in solid form. Significant FindingsThe XRD, XPS and FT-IR results showed that the magnetite particles (Fe3O4) were mainly formed on the surface of all samples, but their content was strongly dependent on the preparation method and the amount of iron. Additionally, the formation of Fe2O3, Fe2C, FeCO3, and FeOOH species on the surface was determined. The highest surface area and microporosity were obtained for the Fe-BC sample prepared by IP (Fe-BC-IP):850 m2/g and 0.28 cm3/g, respectively. A novel and fast electrochemical sensing platform for the detection of H2O2 with a broad linear range (0.5-10 mM) and high sensitivity (621 µA mM−1 cm−2) was fabricated. The findings demonstrate that the non-enzymatic BC-IP sensor is a useful alternative for measuring H2O2.

Electronic Structure Regulation and Surface Reconstruction of Iron Diselenide for Enhanced Oxygen Evolution Activity.

Regulating the electronic structure of active sites and monitoring the evolution of the active component is essential to improve the intrinsic activity of catalysts for electrochemical reactions. Herein, a highly efficient pre-electrocatalyst of iron diselenide with rich Se vacancies achieved by phosphorus doping (denoted as P-FeSe2 ) for oxygen evolution reaction (OER) is reported. Systematically experimental and theoretical results show that the formed Se vacancies with phosphorus doping can synergistically modulate the electronic structure of FeSe2 and facilitate OER kinetics with the resulting enhanced electrical conductivity and electrochemical surface area. Importantly, the in situ formed FeOOH species on the surface of the P-FeSe2 nanorods (denoted as P-FeOOH(Se)) during the OER process acts as an active component to efficiently catalyze OER and exhibits a low overpotential of 217 mV to reach 10 mA cm-2 with good durability. Promisingly, an alkaline electrolyzer assembled with P-FeOOH(Se) and Pt/C electrodes requires an ultra-low cell voltage of 1.50 V at 10 mA cm-2 for overall water splitting, which is superior to the RuO2 || Pt/C counterpart and most of the state-of-the-art electrolyzers, demonstrating the high potential of the fabricated electrocatalyst by P doping strategy to explore more highly efficient selenide-based catalysts for various reactions.

Metal-Impregnated Petroleum Coke-Derived Activated Carbon for the Adsorption of Arsenic in Acidic Waters.

The efficacy of metal-impregnated petroleum coke (PC) activated carbon for the adsorption of arsenite and arsenate in acidic waters is investigated in this study. Unmodified PC activated carbon, FeCl3-loaded activated carbon, KMnO4-loaded activated carbon, and a mixed FeCl3-KMnO4-loaded activated carbon were used for evaluation. The surface characteristics of the activated carbons before and after arsenic adsorption were analyzed by X-ray photoelectron spectroscopy (XPS). Arsenate adsorption was significantly improved by the addition of an iron-manganese-loaded activated carbon, increasing adsorption from 8.12 to 50.93%. Oxidation-reduction reactions are proposed based on the observed arsenic 2p3/2, iron 2p3/2, and manganese 2p3/2 XPS peaks. While iron in the iron-loaded activated carbon is not acting as the reducing agent, it is acting as a conductor for the flow of electrons from the activated carbon to the arsenic for reduction to take place prior to the physisorption of the arsenic. In the manganese-loaded activated carbon, manganese acts as the reducing agent for arsenic prior to arsenic adsorption to the surface through physisorption. XPS of the post-arsenic(V) exposure samples showed that the Fe2O3 species were reduced from 32.18 to 1.66% in the FeMn-loaded sample, while the FeOOH species were increased from 53.16 to 81.71%. Similarly, MnO in the FeMn-loaded activated carbon dropped from 26.82 to 15.40%, while MnOOH and MnO2 increased from 39.98 and 33.20 to 43.96 and 40.64%, respectively. This is consistent with the proposed mechanism. The adsorption of arsenite was also evaluated to show that the modification of the activated carbon adsorbed not only the arsenic(V) species but also the more toxic arsenic(III) species without the need for oxidation of the arsenic prior to adsorption.

Edge atomic Fe sites decorated porous graphitic carbon as an efficient bifunctional oxygen catalyst for Zinc-air batteries

The development of advanced bifunctional oxygen electrocatalysts for oxygen reduction and evolution reactions (ORR and OER) is critical to the practical application of zinc-air batteries (ZABs). Herein, a silica-assisted method is reported to integrate numerous accessible edge Fe-Nx sites into porous graphitic carbon (named Fe-N-G) for achieving highly active and robust oxygen electrocatalysis. Silica facilitates the formation of edge Fe-Nx sites and dense graphitic domains in carbon by inhibiting iron aggregation. The purification process creates a well-developed mass transfer channel for Fe-N-G. Consequently, Fe-N-G delivers a half-wave potential of 0.859 V in ORR and an overpotential of 344 mV at 10 mA cm−2 in OER. During long-term operation, the graphitic layers protect edge Fe-Nx sites from demetallation in ORR and synergize with FeOOH species endowing Fe-N-G with enhanced OER activity. Density functional theory calculations reveal that the edge Fe-Nx site is superior to the in-plane Fe-Nx site in terms of OH* dissociation in ORR and OOH* formation in OER. The constructed ZAB based on Fe-N-G cathode shows a higher peak power density of 133 mW cm−2 and more stable cycling performance than Pt/C + RuO2 counterparts. This work provides a novel strategy to obtain high-efficiency bifunctional oxygen electrocatalysts through space mediation.

Rational Design of Molybdenum-Doped Cobalt Nitride Nanowire Arrays for Robust Overall Water Splitting.

Rational design of efficient electrocatalysts is highly imperative but still a challenge for overall water splitting. Herein, we construct self-supported Co3 N nanowire arrays with different Mo doping contents by hydrothermal and nitridation processes that serve as robust electrocatalysts for overall water splitting. The optimal Co3 N-Mo0.2 /Ni foam (NF) electrode delivers a low overpotential of 97 mV at a current density of 50 mA cm-2 as well as a highly stable hydrogen evolution reaction (HER). Density functional theory (DFT) calculations prove that Mo doping can effectively modulate the electronic structure and surface adsorption energies of H2 O and hydrogen intermediates on Co3 N, leading to improved reaction kinetics with high catalytic activity. Further modification with FeOOH species on the surface of Co3 N-Mo0.2 /NF improves the oxygen evolution reaction (OER) performance benefiting from the synergistic effect of dual Co-Fe catalytic centers. As a result, the Co3 N-Mo0.2 @FeOOH/NF catalysts display outstanding OER catalytic performance with a low overpotential of 250 mV at 50 1 mA cm-2 . The constructed Co3 N-Mo0.2 /NF||Co3 N-Mo0.2 @FeOOH/NF water electrolyzer exhibits a small voltage of 1.48 V to achieve a high current density of 50 mA cm-2 at 80 °C, which is superior to most of the reported electrocatalysts. This work provides a new approach to developing robust electrode materials for electrocatalytic water splitting.

Self‐Supporting Iron‐Modified Nickel Phosphide Electrode Realizing Superior Bifunctional Performance for Water Splitting

AbstractUtilizing non‐noble metal‐based materials to design highly active and low‐cost bifunctional electrocatalysts play a vital role in oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) for the overall water splitting. Herein, a self‐supporting nickel phosphide electrode with the decoration of FeOOH species is successfully prepared by a simple electrodeposition and maceration drying process. This kind of electrode exhibits superior bifunctional activity for both HER and OER. Benefiting from the more exposed catalytic active sites, open hierarchical structure, and better reaction kinetics. At the current density of 100 mA cm−2, the optimal Ni2P−FeOOH/NF delivers the small overpotentials of 200 mV and 235 mV for HER and OER in an alkaline solution, respectively. After further assembling into the electrolyzer, the Ni2P−FeOOH/NF‐based device shows a lower cell voltage of 1.5 V and 1.66 V to reach the current density of 10 mA cm−2 and 100 mA cm−2, along with superior stability. This work outlines a promising strategy for the facile preparation of self‐supporting electrodes for practical application in hydrogen generation by overall water splitting.

Laser-induced immobilization of an amorphous iron-phosphate/Fe3O4 composite on nickel foam for efficient water oxidation.

A laser-induced immobilization strategy is applied to prepare an amorphous iron-phosphate/Fe3O4 (L-FePO) composite on a nickel foam (NF) support. By laser-irradiating an iron hydrogen phosphate (FeHP) precursor, a melting and oxidation process leads to the generation of L-FePO with hierarchical pores and an amorphous structure. L-FePO shows exceptional electrocatalytic performance for the OER in an alkaline electrolyte, demonstrating an overpotential of 256 mV at 100 mA cm-2, a Tafel slope of 71 mV dec-1, and good stability over 100 h. The active Fe3O4, partially dissolved phosphate, and newly formed FeOOH species provide abundant active sites, contributing to the excellent OER performance.

Effect of ferric ions on surface sulfidization of hemimorphite and implications for xanthate adsorption

• Addition of Fe 3+ weakened the surface activity of hemimorphite. • The sulfidization of hemimorphite was depressed in the presence of Fe 3+ . • Adsorption of xanthate on hemimorphite surfaces was hindered by Fe 3+ . The existence of ferric ions (Fe 3+ ) in the pulp solution will severely affect the surface properties and flotation performance of targeted minerals, so its specific effect on the interaction of flotation reagents with the mineral surface must be understood. In this work, the effect of Fe 3+ on the surface sulfidization of hemimorphite was investigated, and the interaction mechanism of Fe 3+ with the hemimorphite surface was clarified. The results of time-of-flight secondary-ion mass spectrometry and X-ray photoelectron spectroscopy indicated that the addition of Fe 3+ before sulfidization generated Fe–OOH species and hindered the formation of active sulfide species on hemimorphite particles. Infrared spectroscopy and contact-angle measurements showed that the addition of Fe 3+ was detrimental to the adsorption of xanthate species on hemimorphite particles, prohibiting the formation of hydrophobic hemimorphite surfaces in the Fe 3+ –sulfidization–xanthate system. Thus, the presence of Fe 3+ in the pulp of hemimorphite was not conducive to the formation of the desired sulfidization products and stable adsorption layers of xanthate on its surface, resulting in unsatisfactory floatability of zinc oxide minerals containing hemimorphite.

Degradation mechanism of surface hydrophobicity by ferrous ions in the sulfidization flotation system of smithsonite

Metal ions commonly exist in the flotation pulp, which will affect the mineral surface properties and lead to a change in the mineral floatability. In this work, the effect of Fe2+ on the flotation behavior of smithsonite was investigated, and the interaction mechanism of Fe2+ with the smithsonite surface in the sulfidization flotation system was clarified. The results of microflotation tests showed that the presence of Fe2+ can greatly reduce the flotation recovery of smithsonite. The results of zeta-potential measurement, time-of-flight secondary-ion mass spectrometry, and X-ray photoelectron spectroscopy indicated that addition of Fe2+ before sulfidization generated FeOOH species and hindered formation of active sulfide species on smithsonite. The results of infrared spectroscopy and contact-angle measurement showed that addition of Fe2+ was harmful for adsorption of the collector on smithsonite, and it was difficult to obtain hydrophobic smithsonite surfaces in the Fe2+–sulfidization–xanthate flotation system. Considering the above results, the presence of Fe2+ depressed adsorption of sulfide ions and the collector on smithsonite, making smithsonite show poor floatability, and it was difficult to obtain the ideal flotation recovery of smithsonite.

Boosting oxygen evolution reaction activity and durability of phosphate doped Ni(OH)2/FeOOH hierarchical microtubes by morphology engineering and reconstruction strategy

Developing electrocatalysts with remarkable activity and durability is significant for efficient oxygen evolution reaction (OER). Herein, we designed phosphate doped Ni(OH)2/FeOOH hierarchical microtubes (denoted as POx-Ni(OH)2/FeOOH HMTs), obtained by phosphate doped NiFe Prussian blue analogue hierarchical microtubes (denoted as P-NF-PBA HMTs) completely reconstructing in OER process. POx-Ni(OH)2/FeOOH HMTs possess an extremely low overpotential of 237 mV at 30 mA cm−2 in alkaline electrolyte with the Tafel slope of 35 mV dec−1, and the catalysts can maintain excellent durability for 100 h at 30 mA cm−2. The remarkable electrochemical catalytic activity comes from the advantages of the hierarchical hollow structure, the modulation of electronic structure caused by phosphate doping, and the synergistic effect of Ni(OH)2 and FeOOH species produced by catalyst complete reconstruction in the OER process. This work may provide an effective strategy to develop highly efficient and durable electrocatalysts towards OER.

Interaction mechanism of Fe3+ with smithsonite surfaces and its response to flotation performance

Iron ions are commonly present in flotation systems. They affect the pulp environment and mineral surface properties, and this changes the mineral floatability. In this work, the effects of Fe3+ on the surface sulfidization characteristics and collector adsorption on smithsonite surfaces were investigated. The results of microflotation tests showed that the addition of 7.5 × 10−4 mol/L Fe3+ decreased the flotation recovery of smithsonite from 49%, which was the recovery achieved by direct sulfidization–xanthate flotation, to 2%. Zeta potential analysis, time-of-flight secondary ion mass spectrometry, and X-ray photoelectron spectroscopy showed that addition of Fe3+ to the pulp reduced the number of active sites on the smithsonite surface and generated hydrophilic Fe–OOH species on the mineral surface. This decreased the reactivity of the mineral surface. The sulfide content of the smithsonite surface after the addition of Fe3+ was lower than that after direct sulfidization. Infrared spectroscopic analysis and contact angle measurements proved that xanthate adsorption on the smithsonite surface was hindered by the addition of Fe3+, which led to poor floatability of the smithsonite.

Self pH regulated iron(II) catalyst for radical free oxidation of benzyl alcohols

Selective oxidation of various aromatic benzyl alcohols to benzaldehydes was found to be catalyzed with 90% conversion and 99% selectivity by an iron (II) catalyst herein designated as Fe-DDPA [DDPA = 3′-disulfanediyldipropionic acid]. The Fe-DDPA catalyst was prepared by a small loading of FeCl2 into a 2D sheet formed by the supramolecular assembling of DDPA. From both solid and liquid state nuclear magnetic resonance (NMR) spectroscopic study it was evident for the stabilization of the Fe(II) center through Fe-S interaction with the disulfide (S-S) unit of DDPA. DDPA was found to serve as an excellent support to maintain a pH that was required for a radical free oxidation of benzyl alcohol to aldehydes. The catalytic oxidation of benzyl alcohols was found to occur with excellent conversion and selectivity in acetonitrile (CH3CN) solvent in comparison to various other solvents. From various spectroscopic studies viz UV-vis, FT-IR and ESI-MS it was ascertained that the CH3CN interacted with Fe-DDPA to form a [(DDPA)2Fe(CH3CN)2]2+ species which then reacted with H2O2 to form an intermediate Fe-hydroxoperoxo, FeIII-OOH species. The Fe-OOH further got oxidized to the active FeIV=O species and was responsible for bringing the high selectivity in the oxidation reaction. The generation of highly unstable Fe-OOH species was further confirmed by electrochemical study, UV–vis, Raman and ESR spectroscopic analysis.

Equilibrium, kinetics, and mechanism of lead adsorption using zero-valent iron coated on diatomite

The lead adsorption performances of zero-valent iron coated on diatomite (ZVI-D) were investigated. ZVI-D was prepared by impregnation of diatomite with iron sulfate solution, and followed by reducing with sodium borohydride. The zero-valent iron of ZVI-D was confirmed by XPS. The adsorption performances were tested in a batch reactor with an initial lead concentration in the range of 100–1,250 mg/L. It was found that a lead adsorption isotherm could be described by Langmuir equations with a maximum adsorption capacity of 158.73 mg/g at 298 K. The mean adsorption energy (E) of 54.78 kJ/mol was determined by using Dubinin–Radushkevich isotherm. The kinetics of Pb2+ adsorption was fitted with a pseudo-second-order model. From the thermodynamic study, it was found that the adsorption process was endothermic and spontaneous. An adsorption mechanism was proposed by using XPS data. Three steps of the adsorption were suggested, (i) Pb2+ ions were oxidized to Pb0 on ZVI active sites, (ii)ferrous ions reacted with the Pb2+ to form FeOPbOH, PbO–Fe, PbO2-–Fe2O3, and PbO–FeOOH species on ZVI surface, and (iii) Pb2+ turned to PbO2–Si, PbO–Si, Pb(OH)2–Al, and PbO2–Al2O3 on diatomite surface.

A structural and functional model for the 1-aminocyclopropane-1-carboxylic acid oxidase.

The hitherto most realistic low-molecular-weight analogue for the 1-aminocyclopropane-1-carboxylic acid oxidase (ACCO) is reported. The ACCOs 2-His-1-carboxylate iron(II) active site was mimicked by a TpFe moiety, to which the natural substrate ACC could be bound. The resulting complex [Tp(Me,Ph) FeACC] (1), according to X-ray diffraction analysis performed for the nickel analogue, represents an excellent structural model, featuring ACC coordinated in a bidentate fashion-as proposed for the enzymatic substrate complex-as well as a vacant coordination site that forms the basis for the first successful replication also of the ACCO function: 1 is the first known ACC complex that reacts with O2 to produce ethylene. As a FeOOH species had been suggested as intermediate in the catalytic cycle, H2 O2 was tested as the oxidant, too, and indeed evolution of ethylene proceeded even more rapidly to give 65 % yield.

Surface alteration mechanism and topochemistry of iron in tremolite asbestos: A step toward understanding the potential hazard of amphibole asbestos

Non-occupational, environmental and unintentional exposure to fibrous tremolite, one of the most widespread naturally occurring asbestos, represents a potentially significant geological risk in several parts of the world. The toxicity of amphibole asbestos is commonly related to iron content and oxidation state, but information available on surface iron topochemistry and amphibole alteration mechanism is still rather poor. With the aim to shed a light on this mechanism, two tremolite samples, one from Italy (Castelluccio) and one from USA (Maryland), immersed in a buffer solution (pH7.4) with H2O2 were characterized by a multi-technique approach. X-ray photoelectron spectroscopy (XPS) and high resolution–transmission electron microscopy (HR-TEM) were used to investigate the surface chemistry of the incubated samples and to detect structural modifications of the fibres, while inductively coupled plasma optical emission spectrometry (ICP-OES) was used to determine the concentration of dissolved elements.An original four-step model for amphibole alteration pathway is proposed. The alteration process starts with an incongruent dissolution of the amphiboles that produces an amorphous, altered surface layer and that is followed by iron oxidation and formation of FeOOH species. Then the congruent dissolution of the altered layer starts and, subsequently, the residual Fe oxi-hydroxides aggregates and insoluble, Fe-rich, amorphous nanoparticles on top of the fibres are formed. The results are compared to those obtained on crocidolite, a highly toxic amphibole asbestos with a 10 to 20 times higher iron content than tremolite. The high chemical reactivity observed in the literature for tremolite appears to be related not only to its iron content and oxidation state, but also to the low nuclearity of iron on the altered surfaces, in contrast to pronounced Fe clusterization at crocidolite surfaces. This is a significant step toward a conceivable explanation of why asbestos tremolite is potentially as toxic as crocidolite.

The study of transition on NiFe2O4 nanoparticles prepared by co-precipitation/calcination

In this study, the NiFe2O4 nanoparticles have been prepared by co-precipitation and calcination process. Using a vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive spectrometer of X-ray (EDX), and X-ray photoelectron spectroscopy (XPS), the samples obtained by co-precipitation and then by further calcination have been analyzed. The experimental results show that the precursor synthesized by co-precipitation is the composite of both amorphous FeOOH and Ni(OH)2, but has no amorphous NiFe2O4. The results of both EDX and XPS revealed that the FeOOH species is wrapped up by Ni(OH)2 species. In the calcination process, the amorphous composite is dehydrated and transformed gradually into crystalline NiFe2O4 nanoparticles, with the metal ions diffusing. The reaction is different from the one used to prepare other ferrite (e.g., CoFe2O4, MnFe2O4, Fe3O4, etc.) nanoparticles directly by co-precipitation. With increasing calcination temperature, the NiFe2O4 grains grow and the magnetization is enhanced.

Photocatalytic degradation of hydroquinone using HFO supported polymeric material

Photocatalytic degradation of hydroquinone (HQ) has been investigated using polystyrene-divinyl benzene polymeric hybrid ion exchange (HIX) resin. The polymeric material was modified with iron cations and thermally treated at 60°C to produce nano FeOOH species (HFO) supported on the HIX polymer and denoted as Fe-HIX. The obtained material was characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM). The data obtained for the degradation of HQ indicate that the addition of Fe-HIX material to the degraded HQ solution greatly enhance the rate of degradation in the presence of H2O2. Since the rate of degradation was found to be governed by the adsorption mechanism, so the adsorption isotherms were established in dark at different pH values and different doses from resin correlated with the obtained data of degradation.