Preparation and physical/electrochemical characterization of Pt/poly(vinylferrocenium) electrocatalyst for methanol oxidation

Preparation and characterization of a platinum (Pt)-based catalyst using a redox polymer, poly(vinylferrocenium) (PVF⁺), as the support material was described. Pt was obtained from aqueous solution of K₂PtCl₄ in the complex form. Pt particles were reduced by chemical and electrochemical means. Chemical reduction was performed using aqueous hydrazine solution and electrochemical reduction was carried out in H₂SO₄ solution. The Pt/PVF⁺ catalyst system showed catalytic activity towards methanol oxidation. Cyclic voltammetry was used for the electrochemical characterization of the catalyst system. Scanning electron microscopy (SEM) images and energy dispersive X-ray spectrum (EDS) of the catalyst system were also recorded. The system was tested in a single fuel cell configuration at ambient temperature and atmospheric pressure. The open circuit voltage (OCV) was 680 mV for the system and the maximum power density was 0.31 mW cm⁻² at a current density of 0.63 mA cm⁻². Catalytic activity of Pt/PVF⁺ system towards methanol oxidation was comparable with the related catalysts in the literature.     

The Fe3+ role in decreasing the activity of Nafion-bonded IrO2 catalyst for proton exchange membrane water electrolyser

Fe³⁺ is a common ion contaminant for the proton exchange membrane water electrolyser (PEMWE). In this work, three-electrode-system was employed to study the effect of Fe³⁺ on Nafion-bonded IrO₂ catalyst which is conventional anode catalyst for PEMWE. Study results showed that Fe³⁺ contamination decreased IrO₂ catalytic activity significantly only when the following two conditions were both satisfied: 1) Nafion resin exists in working electrode; 2) working electrode potential was over 1.471 V (vs. NHE) which is around the initial voltage of oxygen evolution reaction (OER). Besides, the contaminated working electrode activity was recovered to about 16% by being immersed into 3 M H₂SO₄ solution, but it was recovered to about 59% by ethanol washing method. These study results revealed that Fe³⁺ plays a role of catalyst for H₂O₂ production during OER process, which leads to Nafion resin decomposition. The degradation products covered working electrode surface, and thus decreased effective active sites of IrO₂. Nafion degradation was further confirmed by analyzing 1) F⁻ content in anode water and 2) FTIR of contaminated Nafion membrane.     

Phosphate adsorption on chemically modified sugarcane bagasse fibres

Integral sugarcane bagasse fibres of about 2 cm length that were pre-treated for removal of greases and sugars were carboxymethylated on their surface, retaining about 20% of impurities (as insoluble material and water). The fibres were doped with Fe²⁺ ion, by dipping in aqueous iron chloride solutions of different concentrations. This material was used to remove phosphate from water. Thermal analyses (differential scanning calorimetry – DSC) and infrared spectroscopy – FTIR show the occurrence of important changes on carboxymethylated fibres after incorporation of Fe²⁺ and PO₄^3-. Non-carboxymethylated fibres, also treated with the iron solutions, also showed a good level of capture of phosphate from an aqueous solution. The chemical modification increases Fe²⁺ ion adsorption on the fibre surface, increasing the efficiency of phosphate adsorption. Apparently, the process of modification, without incorporation of Fe²⁺, also improves phosphate retention. When about 4% of iron is adsorbed on the fibres, 97% of phosphate is captured on the carboxymethylated material and 94% on the non-carboxymethylated material. The absorption data fit both the Langmuir and Freundlich isotherm. When quantified by measuring the monolayer adsorption in the Langmuir isotherm model, the presence of Fe²⁺ ions on the surface fibres increases the phosphate adsorption capacity by about 45%. Our results (Q max = 152 mg/g) are far superior or in the same order of magnitude, when compared with literature data, with the advantage be the raw material, waste of biomass, only somewhat changed chemically and even after the modifications compose materials harmless to the environment.     

Synthesis and characterization of Pt/ZnO@SWCNT/Fe3O4 as a powerful catalyst for anodic part of direct methanol fuel cell reaction

Platinum is a preferred metal in fuel cell applications owing to its superior catalytic activity; Platinum's high cost and CO poisoning in oxidation processes, limit its usage as a standalone catalyst. At this point, it is important to develop new intermediate tolerant electrocatalysts. In this study, Zinc Oxide/Single Wall Carbon Nanotube/Iron oxide (ZnO@SWCNT/Fe₃O₄₎ catalyst was obtained by using ZnO, SWCNT/Fe₃O₄ support material, and Zinc Oxide/Single Platinum/Wall Carbon Nanotube/Iron oxide (Pt/ZnO@SWCNT/Fe₃O₄₎ catalyst was obtained by chemical synthesis method by adding Pt metal. With these catalysts, the efficiency of the use of Pt was examined within the scope of the study, and reducing limiting factors by using a low amount of Pt, at the same time, it is aimed to prepare a high electrocatalyst. The morphological structure of the obtained catalysts was characterized by scanning electron microscope (SEM), and X-ray diffraction (XRD). Methanol oxidation reactions (MOR) were conducted to determine the electrochemical performance of the catalysts. In the results obtained, it was observed that the current value obtained as a result of the Cyclic Voltammetry (CV) of the ZnO@SWCNT/Fe₃O₄ catalyst was 103.36 mA/cm², and the current value obtained as a result of the CV of the Pt/ZnO@SWCNT/Fe₃O₄ catalyst was 362.46 mA/cm². The results showed high stability for both catalysts, and it was seen that Pt increased the conductivity, methanol oxidation performance, and stability in the catalyst. The obtained catalysts showed high potential for methanol oxidation and are promising for fuel cell applications.     

Advance electrochemical oxidation of fipronil contaminated wastewater by graphite anodes and sorbent nano hydroxyapatite

Degradation of C₁₂H₄Cl₂F₆N₄OS phenylpyrazole insecticide (Fipronil) by advance electrochemical oxidation in aqueous water solution was studied. The process efficiency was figured based on the COD, chloride, and fluoride reduction from fipronil. Further, we tried to highlight the importance of nano-hydroxyapatite (n-Hap) as a cost-effective nano sorbent for removal of fluoride from fipronil. From the advance electrochemical oxidation experiment, it was found that the COD removal was 79%, chloride 52%, and fluoride 80%. The intermediate of fipronil compounds was examined by GC-MS. The final results conclude that advance electrochemical oxidation process was effective for removal of fipronil synthetic wastewater.     

Fenton degradation of 4-chlorophenol contaminated water promoted by solar irradiation

The degradation of 4-chlorophenol (4-CP) contaminated water by Fenton process with or without solar irradiation assistance were investigated. It was found that the COD degradation and mineralization efficiency of 4-CP were more than 90% when a 30 min treatment of solar photo-Fenton oxidation process was applied and under an optimum [H₂O₂]₀/[Fe²⁺]₀ ratio of 40, the COD degradation and mineralization efficiency increased 65% as compared to Fenton oxidation. Meanwhile, the AOS values increased from −0.33 to 2.13 in solar photo-Fenton process while no significant improvement for AOS values was found in Fenton process, implying a higher degree of oxidation for 4-CP in solar photo-Fenton process. In addition, increasing the intensity of solar irradiation seemed to be beneficial for treatment of 4-CP contaminated water. Formation of chloride ion as a result of mineralization of organically bounded chlorine was identified during the treatment of 4-CP solution. Near-stoichiometric accumulation of chlorine was observed during the degradation of 4-CP in both Fenton and solar photo-Fenton processes. However, accumulation rate of chloride ions were much faster in solar photo-Fenton process. The degradation of 4-CP was found to obey a pseudo-first-order reaction kinetics. As compared to Fenton process, the presence of solar light in photo-Fenton process increases the reaction rate by a factor of 6.5 and 15.8 for COD and TOC degradation, respectively. In other words, during the treatment of 4-CP contaminated water, solar photo-Fenton process possesses notably higher mineralization efficiency in a relatively short radiation time as compared to Fenton process, and could enhance the degradation treatment of refractory organic wastewater such as 4-CP in a cost-effective approach.     

Treatment of dairy wastewater using anaerobic and solar photocatalytic methods

The present study was aimed to treat the dairy wastewater by using anaerobic and solar photocatalytic oxidation methods. The anaerobic treatment was carried out in a laboratory scale hybrid upflow anaerobic sludge blanket reactor (HUASB) with a working volume of 5.9 L. It was operated at organic loading rate (OLR) varying from 8 to 20 kg COD/m³ day for a period of 110 days. The maximum loading rate of the anaerobic reactor was found to be 19.2 kg COD/m³ day and the corresponding chemical oxygen demand (COD) removal at this OLR was 84%. The anaerobically treated wastewater at an OLR of 19.2 kg COD/m³ day was subjected to secondary solar photocatalytic oxidation treatment. The optimum pH and catalyst loading for the solar photochemical oxidation was found to be 5 and 300 mg/L, respectively. The secondary solar photocatalytic oxidation using TiO₂ removed 62% of the COD from primary anaerobic treatment. Integration of anaerobic and solar photocatalytic treatment resulted in 95% removal of COD from the dairy wastewater. The findings suggest that anaerobic treatment followed by solar photo catalytic oxidation would be a promising alternative for the treatment of dairy wastewater.     

An electrochemical strategy of doping Fe into TiO2 nanotube array films for enhancement in photocatalytic activity

Highly ordered Fe³⁺-doped TiO₂ nanotube array films were fabricated directly by the electrochemical anodic oxidation of pure titanium in an HF electrolyte solution containing iron ions. The morphology, structure and composition of the as-prepared nanotube array films were characterized by SEM, Raman and XPS. The effects of dopant amount on the morphologies, structure, photoelectrochemical property and photoabsorption of the TiO₂ nanotube array film were investigated. The results showed that Fe³⁺ was successfully introduced into the nanotube array film. Compared with the undoped TiO₂ nanotube array film, the photocurrent of Fe³⁺-doped TiO₂ nanotube array films increased obviously. The absorption edge of Fe³⁺-doped TiO₂ nanotube array films appeared to be red shifted. The photocatalytic activity of Fe³⁺-doped TiO₂ nanotube array films was evaluated by the removal of methylene blue (MB) aqueous solution. A maximum enhancement of photocatalytic activity was achieved for Fe³⁺-doped TiO₂ nanotube array film prepared in 0.10 M Fe(NO₃)₃+0.5% HF electrolyte under UV irradiation, which attributes to the effective separation of photogenerated electron–hole upon the substitutional introduction of appropriate Fe³⁺ amount into the anatase TiO₂ structure.     

Hydrogen-based sono-hybrid catalytic degradation and mitigation of industrially-originated dye-based pollutants

Hazardous pollutants in water bodies have increased global concern due to their considerable toxicity and threat to the environmental matrices. Conventional remediation approaches are futile for eliminating various toxic dyes and other related pollutants. Regulations compliances for wastewater expulsion have forced scientists to either introduce new methods or upgrade present technologies to attain operative deprivation and mineralization of pollutants. Advanced oxidation processes (AOPs) relying on the generation of highly reactive oxidizing radicals, like ^?O, and ^?OH are considered efficient to attain high mineralization of a large number of dye pollutants and many other organic contaminants. Compared to conventional AOPs, including photocatalysis, Fenton, photo-ferrioxalate, ozone/UV, ozonation, H₂O₂/UV, etc., sonolysis is a comparatively newer AOP that implicates the use of ultrasound irradiation for generating oxidizing radicals, leading to the degradation of recalcitrant dyes. Due to no chemical catalyst requirement and being executed at ambient pressure and temperature, ultrasound-assisted AOPs have become robust hybrid AOPs to degrade environmental contaminants. Ultrasound treatments to mitigate pollutants are important because of the cavitation phenomenon. This review focuses on the degradation of dyes through ultrasound-based advanced oxidation processes. Firstly, we have described the ecotoxicity and health hazards of dye pollutants, then different sono-based methods such as sono-hybrid Fenton (US + Fe⁺²/H₂O₂), Fenton like (Fe⁺³/H₂O₂) process, sono-hybrid photo-Fenton process (US + Fe²⁺/H₂O₂/UV system, sono-hybrid hydrogen peroxide (US + H₂O₂), sono-hybrid catalytic (photo/electro) processes have been examined in details for their efficacy for degradation of dyes in wastewater. Future perspectives of ultrasound-assisted AOPs for dyes removal have also been discussed.     

TiO2-assisted degradation of acid orange 7 textile dye under solar light

Photocatalytic degradation of acid orange 7 (AO7) in aqueous systems was successfully achieved by the combination of TiO₂ with potassium persulphate under solar light using a photochemical reactor with recirculation. Degradation of AO7 involves color removal and mineralization. The employment of TiO₂ removed 85% of color from the 0.2 mM AO7 aqueous solution under solar light; while, 66% of color was abated using the persulphate ion as oxidant in the absence of TiO₂ under similar conditions in 2 h. However, over 90% of color removal was achieved by combining TiO₂ and the persulphate ion for the same solution under similar conditions. Color removal was faster at pH 3. Mineralization of AO7 was followed by measuring chemical oxygen demand (COD). Negligible COD abatement of the textile dye was observed in the absence of persulphate ions (S₂O₈²⁻) while over 70% of COD abatement was observed for the initial dye concentrations of 0.2–0.7 mM employing a mix of TiO₂–S₂O₈²⁻ under solar light.     

Accelerated durability tests of catalyst layers with various pore volume for catalyst coated membranes applied in PEM fuel cells

The effect of pore volume on the catalyst layer durability of PEM fuel cell was simulated by soaking the catalyst coated membrane (CCM) into H₂O₂/Fe²⁺ solution. Before this simulation, the CCM with various pore volumes in catalyst layer was fabricated. The structure of catalyst layers was optimized with an increase in pore volume, leading to an improvement of fuel cell performance. However, this treatment causes a negative effect on the lifetime of CCM especially when H₂O₂/Fe²⁺ introduced. As a result, the catalyst layer with high pore volume has a higher detaching rate than that with low pore volume. The detaching of catalyst layers could be attributed to degradation of both the recast Nafion in catalyst layers and the Nafion membrane. The catalyst layer with high pore volume accelerates the recast Nafion degradation. Thus, the durability of membrane electrode assembly should be considered when the catalyst layer is optimized.     

Catalytic partial oxidation of coke oven gas to syngas in an oxygen permeation membrane reactor combined with NiO/MgO catalyst

A high oxygen permeability and sufficient chemical and mechanical stability mixed ion and electron conductivity membrane to withstand the hash strong oxidation and reduction working conditions is significant for the membrane reactor to commercial-scale plant. In this paper, a disk-shaped Ba_1.0Co_0.7Fe_0.2Nb_0.1O_3−δ membrane was applied to a membrane reactor for the partial oxidation of methane in coke oven gas (COG) to syngas. The reaction was carried out using NiO/MgO solid solution catalyst by feeding COG. The reforming process was performed successfully; 95% CH₄ conversion, 80% H₂ selectivity, 106% CO selectivity and 16.3 ml cm⁻² min⁻¹ oxygen permeation flux were achieved at 1148 K. The reaction has been steadily carried out for more than 100 h. The NiO/MgO catalyst used in the membrane reactor exhibited good catalytic activity and resistance to coking in the COG atmosphere. Characterization of the membrane surface by SEM and XRD after long life test showed that both the surface exposed to the air side and reaction side still preserved the Perovskite structure which is implied that the practical application of this membrane as membrane reactor for partial oxidation of COG is promising.     

Fe7Se8@Fe2O3 heterostructure nanosheets as bifunctional electrocatalyst for urea electrolysis

Water electrolysis for producing hydrogen is considered to be the most feasible means to develop new green energy. Compared with above, urea electrolysis can improve energy conversion efficiency by introducing urea, and can also be used for purification of wastewater rich in urea. In this paper, a bifunctional electrocatalyst with heterostructure, namely Fe₇Se₈@Fe₂O₃ nanosheets supported on nickel foam, were synthesized for the first time through typical hydrothermal and partial oxidation processes. Iron cation promotes electron transfer and adjusts electron structure under the synergistic action of selenium and oxygen anion, thus achieving excellent catalytic activity of urea electrolysis. In an alkaline solution of 1 M KOH with 0.5 M urea, the Fe₇Se₈@Fe₂O₃/NF catalyst can drive the current density of 10 mA cm^?2 with requiring only potential of 1.313 V and overpotential of 141 mV for urea oxidation reaction (UOR) and hydrogen evolution reaction (HER), respectively. What is noteworthy is that Fe₇Se₈@Fe₂O₃/NF heterostructure is used as bifunctional electrocatalyst to form urea electrolyzer device, which only needs potential of 1.55 V to drive current density of 10 mA cm^?2, which is one of the best catalytic activities reported so far, and the electrode couple showed remarkable stability for 15 h. Density functional theory shows that the Fe₇Se₈@Fe₂O₃/NF material exhibits the minimum Gibbs free energy for the adsorption of hydrogen. This work provides a new method for exploring novel and environmentally friendly bifunctional electrocatalysts for urea electrolysis.     

Photocatalytic colour and COD removal in the distillery effluent by solar radiation

The photodegradation of distillery effluent has been studied for removal of colour and COD reduction in the presence of solar radiation. The influence of experimental parameters such as H₂O₂ concentration dosage, effluent COD concentration, TiO₂ catalyst and pH on colour and COD removal efficiency through solar photochemical process has been investigated. Maximum colour removal of the distillery effluent achieved was 79% at an H₂O₂ concentration of 0.3 M, pH 6, effluent COD concentration of 500 ppm and catalyst dosage of 0.1 g/L. The TiO₂/H₂O₂ system seems to be more efficient in comparison to the synergetic action that appears when using H₂O₂ and TiO₂. The photocatalytic degradation process using solar light as an irradiation source showed potential application for the colour removal of the distillery effluent treatment. Solar radiation can be an considered as an alternative, effective and economic energy carrier for the treatment of industrial effluent.     

MgFe and Mg–Co–Fe mixed oxides derived from hydrotalcites: Highly efficient catalysts for COx free hydrogen production from NH3

Mg–Fe Layered Double Hydroxide (LDH) with M²⁺: M³⁺ 3:1 stoichiometric ratio was synthesized and employed as catalyst precursor for CO_x-free hydrogen production from ammonia. The resulting catalyst showed good catalytic activity. A series of Mg/Co–Fe layered double hydroxides were synthesized by replacing Mg²⁺ with Co²⁺ without disturbing M²⁺:M³⁺ ratio. The influence of nature and extent of Co(II) substitution on structure, morphology and surface properties were studied. A systematic study was carried out using these materials as catalyst precursors for ammonia decomposition. BET, XRD, TPR, XPS, CO₂-TPD and TEM techniques were used to characterize the synthesized catalysts. These Fe-based catalysts are highly active, highly stable and not promoting any stable surface nitridation during the ammonia decomposition reaction. Among all catalysts, the Mg₃Co₃Fe₂ catalyst showed the highest activity i.e. 100% conversion at 6,000 h⁻¹ and 60% at 50,000 h⁻¹ space velocities at 550 °C. The registered superior catalytic activity was result of the formed specific catalyst's properties like high surface area, high surface Co and Fe atomic concentration and suitable basicity. These Fe-based materials are, cost-effective, easily synthesize and highly stable, thus attractive for large-scale operation.     

Magnetic field effects on selective catalytic reduction of NO by NH3 over Fe2O3 catalyst in a magnetically fluidized bed

Selective catalytic reduction (SCR) of NO from simulated flue gas by ammonia with Fe₂O₃ particles as the catalyst was performed using a magnetically fluidized bed (MFB). X-ray diffraction (XRD) spectroscopy and Brunauer–Emmett–Teller (BET) method were used to analyze Fe₂O₃ catalyst. Important effects of magnetic fields were observed in the SCR of NO by ammonia over Fe₂O₃ catalyst. The apparent activation energies of SCR were reduced by external magnetic fields, and the SCR activity of Fe₂O₃ catalyst was improved with the magnetic fields at low temperatures. Thus the scope of temperature with high efficiency of NO removal was extended from 493–523 K to 453–523 K by magnetic fields. Magnetic fields of 0.01–0.015 T were suggested for NO removal on Fe₂O₃ catalyst with MFB. The results suggested that the magnetoadsorption of NO onto Fe₂O₃ surface together with NH₂ and NO free radicals effects induced by the external magnetic fields both acted to improve the rate of SCR of NO on Fe₂O₃ catalyst. On the other hand, magnetic field effects were also attributed to improved gas–solid contact in MFB.     

Evaluating chemical degradation of proton conducting perfluorosulfonic acid ionomers in a Fenton test by solid-state F NMR spectroscopy

Chemical degradation and stability of perfluorosulfonic acid (PFSA) ionomers against radical attack were investigated by an (ex situ) Fenton test. Solid-state and solution NMR as well as ATR-FTIR studies were performed on the samples before and after the Fenton reaction. By changing the concentration of the Fenton's solution it is found that the metallic catalyst (Fe²⁺) is a critical factor which may affect the solid-state NMR results. After adjusting the experimental conditions, i.e., by reducing the Fe²⁺ concentration, it was possible to detect by solid-state ¹⁹F NMR spectroscopy the structural changes of the perfluorosulfonic acid ionomers during the ex situ Fenton test.A comparative study was made on the degradation of Nafion and Hyflon Ion membranes which differ in the length of the side chains. It is shown that the Hyflon Ion membrane with shorter side chains is more stable against side chain attack, most probably because of the absence of an additional tertiary carbon in the side chain. At the same time, there is evidence for enhanced main chain degradation in membranes with unprotected backbone chain ends.     

Synthesis of mesoporous Co–Ce oxides catalysts by glycine-nitrate combustion approach for CO preferential oxidation reaction in excess H2

Preferential oxidation of CO (CO-PrOx) is an important step to meet the need of the proton exchange membrane (PEM) fuel cell without the Pt anion poison. A glycine-nitrate approach was used for the synthesis of Co/CeO₂ nanoparticle for preferential oxidation of CO, which a precursor solution was prepared by mixing glycine with an aqueous solution of blended nitrate in stoichiometric ratio. Then the glycine-mixed precursor solution was heated in a beaker for producing nanosized porous powders. Catalytic properties of the powders were investigated and results illustrate that the Co-loading of 30 wt.% catalysts exhibits excellent catalytic properties. Various characterization techniques like X-ray diffraction, SEM, BET, Raman and TPR were used to analyze the relationship between catalyst nature and catalytic performance. The X-ray diffraction patterns and SEM micrographs indicate that catalysts prepared by glycine-nitrate combustion own mesopore structure. The BET, Raman and TPR results showed that the high activity of the 30 wt.% Co-loading of Co/CeO₂ catalysts is related to the high BET surface and the strongly interaction between fine-dispersed Co species and CeO₂ support.     

Ru coated Co nanoparticles decorated on cotton derived carbon fibers as a highly efficient and magnetically recyclable catalyst for hydrogen generation from ammonia borane

Cotton, which has abundant oxygen-containing hydrophilic groups, can adsorb a lot of water or other water soluble materials. In this paper, cotton was impregnated in CoCl₂ aqueous solution. Co²⁺ can be uniformly adsorbed on cotton fibers. After been freeze-dried, the Co²⁺-adsorbed cotton was carbonized under an inert atmosphere and the Co nanoparticles (NPs) modified cotton derived carbon fibers (Co/CCF) were obtained. The Co/CCF was then dispersed in RuCl₃ aqueous solution, so that Ru³⁺ can be reduced by metallic Co NPs through spontaneous replacement reaction and covered on Co NPs surface. Hence, the Ru@Co/CCF catalyst was prepared with low Ru loading in the view of Ru saving. In the catalytic hydrolysis of ammonia borane (NH₃·BH₃, AB), the Ru@Co/CCF catalyst showed excellent catalytic activity as compared with Ru/CCF and many other noble metal based catalysts. The superior activity of the catalyst is mainly due to the highly dispersed Ru@Co NPs on the carbon fibers and the uniform covering of the metallic Ru on the surface of Co NPs. Moreover, owing to the magnetic core of the Ru@Co NPs, Ru@Co/CCF catalyst can be easily separated from the reaction system using an external magnetic field. Thus, this work provided a useful strategy for facile preparation of low precious metals loading catalysts using cheap and environmental starting material as catalyst support precursor material.     

Preferential CO oxidation over Au/ZnO and Au/ZnO–Fe2O3 catalysts prepared by photodeposition

Preferential CO oxidation in a H₂-rich stream was studied over Au/ZnO and Au/ZnO–Fe₂O₃ catalysts prepared by photodeposition under UV–vis light. The high catalytic activities of both Au/ZnO and Au/ZnO–Fe₂O₃ catalysts are presented over a temperature range of 30–130 °C. TEM results revealed that the average particle size of Au over the Au/ZnO and Au/ZnO–Fe₂O₃ catalysts, is in the range of 3–5 nm. Moreover, DR/UV–vis spectra showed that the prepared catalysts contained Au^δ+ and Au⁰ (active sites for the PROX reaction) on the catalyst support. Based on the experiment observations, it can be concluded that the catalysts prepared by a photodeposition exhibited excellent catalytic activity, even when both CO₂ and H₂O were added to the simulated stream.