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Reaction Kinetics and Catalysis Letters

Current research reports and chronological list of recent articles..




Reaction Kinetics and Catalysis Letters is a medium for the rapid publication of original contributions in such fields as kinetics of homogeneous reactions in gas, liquid and solid phase; homogeneous and heterogeneous catalysis; adsorption in heterogeneous catalysis; transport processes related to reaction kinetics and catalysis; preparation and study of catalysts; reactors and apparatus.

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Additional research articles see Current Chemistry Research Articles. Magazines with similar content (reaction kinetics and catalysis):

 - International Journal of Chemical Kinetics.



Reaction Kinetics and Catalysis Letters - Abstracts



Efficient one-pot synthesis of 3-methylindole from biomass-derived glycerol with aniline over Cu/SiO 2 modified with ZnO and Fe 2 O 3 and deep insight into the mechanism

Abstract

An efficient catalyst of Cu/SiO2 modified with ZnO and Fe2O3 was constructed for the one-pot synthesis of 3-methylindole originating from biomass-derived glycerol with aniline. The structure and property of as-prepared Cu/SiO2–ZnO–Fe2O3 composite were characterized by temperature programmed reduction of H2 (H2-TPR), X-ray diffraction (XRD), transmission electron microscope (TEM), temperature programmed desorption (TPD) of NH3 and CO2, inductively coupled plasma (ICP) emission spectroscopy, thermogravimetric and differential thermal analysis (TG–DTA). The results indicated that the interaction between copper and support was improved after adding ZnO to Cu/SiO2, as a result, Cu particles could be firmly anchored on the surface of SiO2–ZnO, which not only increased the dispersion of active component but also inhibited the aggregation or sintering of copper particles effectively. Meanwhile, the acid or base sites on the ZnO modified Cu/SiO2 catalyst significantly increased, which was beneficial to the hydrogenolysis of glycerol to acetol and 1,2-propanediol and promoted the synthesis of 3-methylindole. The introduction of Fe2O3 to Cu/SiO2–ZnO could promote the reduction of CuO and decrease the acidity of the catalyst, thereby the activity and stability of the catalyst were further improved. Under the optimized ZnO or Fe2O3 content of 0.100 or 0.030 mmol/g-SiO2, Cu/SiO2–ZnO–Fe2O3 exhibited excellent catalytic activity and long-term stability, which the yield of 3-methylindole was up to 73% and it was still more than 68% when the catalyst was reused four times. Moreover, the catalytic mechanism for the one-pot synthesis of 3-methylindole from glycerol and aniline over Cu/SiO2–ZnO–Fe2O3 was investigated in depth and a probable synthetic route was proposed based on the research of the catalytic reactions of glycerol, 1,2-propanediol or acetol with aniline as well as the hydrogenolysis of glycerol and the catalytic conversion of acetol, which both acetol and 1,2-propanediol were the intermediates for the production of 3-methylindole.


Datum: 01.10.2019


Kinetic evaluation of the hydroformylation of the post-metathesis product 7-tetradecene using a heterobimetallic rhodium-ferrocenyl Schiff base derived precatalyst

Abstract

Reaction engineering kinetics for the hydroformylation of the post-metathesis product 7-tetradecene using a heterobimetallic rhodium-ferrocenyl Schiff base derived precatalyst was investigated with variation of reaction temperature (85–105 °C), precatalyst loading (0.25–0.52 mM), carbon monoxide partial pressures (20–40 bar) and hydrogen partial pressures (20–40 bar). The experimental product-time distributions for the parallel hydroformylation and isomerization reaction system are well described by four interdependent pseudo first-order differential mole balance equations. The effects of temperature in the Arrhenius equation, precatalyst concentration, carbon monoxide and hydrogen partial pressures have been incorporated into a phenomenological mechanism-based rate equation. The rate of hydroformylation is first order in alkene, carbon monoxide and hydrogen, with fractional dependence in precatalyst concentration. The activation energy for the hydroformylation reaction was calculated to be 62 kJ mol−1, which is comparable to that determined for the commercialized phosphorus-modified catalyst systems.


Datum: 01.10.2019


Molecular reaction kinetics model for the hydrodeoxygenation of low boiling point phenolic compounds in coal tar with Ni–Ce/SiO 2 catalysts

Abstract

In this study, 27 groups of hydrogenation experiments were carried out in a single-tube fixed-bed reactor using 9 phenolic compounds extracted from coal tar (fraction before 240 °C) as raw materials. Based on the experimental results, a set of molecular reaction kinetics model which involve 21 compounds and 33 chemical reactions was established. In this paper, the Runge–Kutta method was used to solve the dynamic equations, and the BFGS algorithm (a quasi-Newton optimization algorithm) is used to optimize the parameters of the dynamic model. The whole calculation process was completed on MATLAB software. The experimental results show that the maximum error of the model for predicting phenolic, unsaturated hydrocarbon and saturated hydrocarbon content in products is less than 5%, while the maximum error for predicting single substance is less than 10%. It could be calculated that the optimum temperature for hydrodeoxygenation of phenolic compounds is 633 K, which aims to retain aromatic hydrocarbons.


Datum: 01.10.2019


Kinetic analysis of azo dye decolorization during their acid–base equilibria: photocatalytic degradation of tartrazine and sunset yellow

Abstract

In this study, the kinetics of the photodegradation of tartrazine (TA) and sunset yellow (SY) was systematically evaluated at different pH values in the presence of α-Fe2O3 nanostructures as a cost-effective and efficient photocatalyst. For each dye, time-spectral data was recorded in the pH range 8–12, then the whole data was resolved by hard soft-modelling parallel factor analysis to obtain the kinetic profiles of the components existing during simultaneous kinetic and equilibria processes. Then, the rate constants of degradation processes together with their uncertainties were computed. The results revealed that pH strongly affects the mechanism and the rate constants of the dyes photoreactivity due to changing the structure of the analytes. In fact, those protonated/deprotonated structures with resonance forms were less degradable because of their stability and then showed lower rate constant(s).


Datum: 01.10.2019


Enhancement of catalytic performance over different transition metals modified CeO 2 for toluene abatement

Abstract

Pure CeO2 and CeO2–MOx (M: Mn, Zr and Ni) catalysts were synthesized by the co-precipitation method and evaluated for the oxidation of toluene. The characterization showed that the specific surface area and the porous texture of catalysts were improved due to the doping of transition metal. Besides, the doping of MOx into ceria contributed to the generation of structural defects, which could contribute to the easier storage and release of surface oxygen. Furthermore, the CeO2–MOx (M: Mn, Zr and Ni) catalysts exhibited higher concentration of Ce3+ and surface adsorbed oxygen than pure CeO2, which could correlate with the generation of oxygen vacancies, resulting in the enhancement of redox properties. Hence, CeO2–MnOx exhibited the best apparent catalytic activity of toluene due to its more Ce3+, structural defects and active oxygen species.


Datum: 01.10.2019


Enhanced hydrothermal stability of a manganese metavanadate catalyst based on WO 3 –TiO 2 for the selective catalytic reduction of NO x with NH 3

Abstract

A catalyst with 1 wt% manganese metavanadate (MnV2O6) based on WO3–TiO2 is prepared and applied to the selective catalytic reduction of NOx with NH3. After hydrothermal aging treatment at 750 °C for 12 h, it performs excellent activity with a wide temperature window. The catalysts are characterized by XRD, BET, DSC, UV–Vis, NH3-TPD and in situ FT-IR. With the introduction of MnV2O6, the sintering and phase transformation of TiO2 from anatase to rutile are suppressed during the aging process. Simultaneously, the excessive agglomeration of vanadium species and growth of crystalline V2O5 are hindered. The superior hydrothermal stability is attributed to the higher melting point of MnV2O6. The strong interaction between V and Mn contributes to maintain the vanadium species and inhibits the promoting effect of free vanadia on sintering and rutilization of support. MnV2O6 based catalyst exhibits higher adsorption capacity and activation ability of ammonia species after aging, which are in favor of the de-NOx activity.


Datum: 01.10.2019


Hierarchical ZSM-5 based on fly ash for the low-temperature purification of odorous volatile organic compound in cooking fumes

Abstract

Hierarchical ZSM-5 (HZ) zeolites with different SiO2/Al2O3 ratios (SiO2/Al2O3 = 50, 100, 150, 200, 250 and 300) were synthesized using a two-step hydrothermal treatment method, and the Al and Si were obtained from fly ash by the alkali melting and acid leaching method. On this basis, the 10 wt% LaMnO3/HZ catalysts were prepared by impregnation. The all the synthesized catalysts were investigated for the low-temperature (200 °C) catalytic oxidation of pentanal, which was selected as a typical odorous volatile organic compound (VOC) in cooking fumes. In addition, the physicochemical properties of HZ zeolites were characterized by several techniques (XRD, N2 physical adsorption–desorption, ICP-OES, SEM,TEM,NH3-TPD and 27Al MAS-NMR). The results showed that the HZ zeolite, which was micro-mesoporous material and had high specific surface area, provided a higher diffuser efficiency for long-chain VOC gas. The catalytic performance of HZ zeolite was better than that of the traditional ZSM-5 zeolite. Compared with the dry atmosphere, HZ-100 zeolite, which possessed more proper medium strong acid sites and the appropriate amount of acid sites, had the higher pentanal catalytic combustion conversion of above 92% and the relatively superior stability with 2 V% water steam in air, indicating that the suitable acid sites can form the best synergistic catalytic effect with water molecules for purifying long-chainVOC gas. In addition, the catalytic conversion of pentanal on 10 wt% LaMnO3/HZ-100 was 100% with no deactivation, and compared with HZ under a dry atmosphere, the average CO2 yields of 10 wt% LaMnO3/HZ catalysts in the steady catalytic oxidation stage under a dry atmosphere and 2 V% water steam in air were improved by 6–18% and 13–20%.


Datum: 01.10.2019


High catalytic activity of gold nanoparticle-templated, tyrosine-rich peptide self-assemblies for 3,3′,5,5′-tetramethylbenzidine oxidation in the absence of hydrogen peroxide

Abstract

In this study, gold nanoparticle-templated, tyrosine-rich peptide (YC7@AuNPs) self-assemblies were examined as peroxidase enzyme–mimic catalysts for the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) and its activity was monitored by changing the reaction conditions such as pH, temperature, initial TMB concentration, and catalyst (Au) loading amount. The YC7@AuNPs catalysts were active for TMB oxidation even in the absence of hydrogen peroxide. Michaelis–Menten kinetic analysis showed that the YC7@AuNPs catalysts without hydrogen peroxide have activities comparable to other peroxidase–mimic catalysts using hydrogen peroxide in terms of the Michaelis constant.


Datum: 01.10.2019


Low temperature hydrogenation and hydrodeoxygenation of oxygen-substituted aromatics over Rh/silica: part 1: phenol, anisole and 4-methoxyphenol

Abstract

The hydrogenation and competitive hydrogenation of anisole, phenol and 4-methoxyphenol was studied in the liquid phase over a Rh/silica catalyst at 323 K and 3 barg hydrogen pressure. The rate of conversion of the reactants to products gave an order of anisole ≫ phenol > 4-methoxyphenol with hydrogenation and hydrodeoxygenation products being produced. Anisole, the most reactive substrate, was rapidly converted to methoxycyclohexane, cyclohexane, cyclohexanone and cyclohexanol, while phenol was hydrogenated to cyclohexanone, cyclohexanol and cyclohexane. In both cases cyclohexanol was produced as a secondary product from cyclohexanone hydrogenation. The yield of cyclohexane, the hydrodeoxygenation (HDO) product was > 20% from both reactants and was formed as a primary product from the aromatic species. Hydrogenation of 4-methoxyphenol was selective to 4-methoxycyclohexanone with no alcohol formation, while the hydrogenolysis products revealed that the catalyst was more active for demethoxylation than dehydroxylation. A comparative strength of adsorption was determined from competitive hydrogenation and gave an order of anisole > phenol > 4-methoxyphenol. Competitive, pair hydrogenation inhibited HDO and stopped cyclohexane from being produced from phenol and 4-methoxyphenol, although it was still produced from anisole. An increased rate of hydrogenation for 4-methoxyphenol was observed for competitive reactions with phenol and anisole but not when all three reactants were present. In contrast to the pair reactions, when all three reactants were present HDO occurred with all aromatics producing cyclohexane. Replacing hydrogen with deuterium revealed an inverse kinetic isotope effect for ring hydrogenation of 4-methoxyphenol but not phenol or anisole, which both had a positive KIE.


Datum: 01.10.2019


Sustainable approach to the synthesis of 1,4-disubstitued triazoles using reusable Cu(II) complex supported on hydroxyapatite-encapsulated α-Fe 2 O 3 as organic–inorganic hybrid nanocatalyst

Abstract

A novel Cu(II) complex supported on hydroxyapatite-encapsulated α-Fe2O3 as organic–inorganic hybrid nanocatalyst (α-Fe2O3@Hap@Cu) was synthesized and used in the preparation of 1,2,3-triazole derivatives under green reaction conditions. In this protocol, water was used as solvent under aerobic conditions at room temperature, with low catalyst loading, while ensuring the recovery and reusability of the catalyst. The catalyst affords excellent selectivity in formation of the desired products in short reaction time (10–35 min) and excellent yields (85–98%). The paramagnetic nature of the catalyst led to its easy and convenient separation by an external magnet and reused for 11 consecutive runs without significant loss in activity. The structure of the catalyst was established by FT-IR, XRD, SEM, TEM, EDX, VSM and TGA analyses.


Datum: 01.10.2019


Hydrogen-transfer hydrodehalogenation of aromatic halides with a silica-supported palladium catalyst in alkaline 2-propanol: comparison between brominated and chlorinated anisoles

Abstract

Hydrogen-transfer hydrodehalogenation of brominated anisoles, chlorinated anisoles, and bromochloroanisoles was carried out at 30–40 °C in a solution of NaOH in 2-propanol/methanol (99:1 V/V) in the presence of a Pd/SiO2 catalyst. The dehalogenation reactions proceeded stepwise to afford anisole, and 2-propanol served as a hydrogen source. In single-substrate reactions, 2,4,6-tribromoanisole (TBA) was dehalogenated more slowly than 2,4,6-trichloroanisole, whereas in a competitive reaction, 2,4,6-TBA was preferentially dehalogenated. The analysis of lower-halogenated intermediates revealed that the ortho halogen was less reactive than the para halogen, and the isomer selectivity of the dehalogenation reaction strongly depended on the halogen atom. The conversion of bromochloroanisoles (3-bromo-4-chloroanisole, 3-bromo-5-chloroanisole, and 2-bromo-4-chloroanisole) to anisole occurred exclusively via the corresponding chloroanisoles. The difference in dehalogenation behavior between the brominated and chlorinated anisoles is discussed on the basis of carbon–halogen bond dissociation energies, steric effects, and substrate adsorption ability.


Datum: 01.10.2019


Preparation of mesoporous silica supported sulfonic acid and evaluation of the catalyst in esterification reactions

Abstract

Sulfonic acid group was chemically bonded on either amorphous or highly ordered mesoporous silica surface through hydrothermal treatment with Na2SO3/NaHSO3 aqueous solution followed by acidification after the silica was grafted with surface propyl-chloride group. N2 adsorption–desorption was used for the characterization of the topology properties of the mesoporous silica–SO3H catalysts and the acid amount was studied by titration. Solid NMR and FTIR techniques were employed for detection of the surface groups and covalently bonded propyl–SO3H species was identified. The solid acid catalyst was evaluated in esterification reactions between various carboxylic acids and short-chain alcohols and the results demonstrated that the mesoporous silica–SO3H catalyst shows not only a high activity comparable to that of reported KIT-6-120–SO3H catalyst, but also an excellent recyclability (without deactivation after reused for eight times in lauric acid esterification with ethanol). The good performance and strong acidic character of the catalyst was correlated with the large pore size, well accessible acid sites as well as covalently grafted active structure on the catalyst.


Datum: 01.10.2019


Correlation of metal–organic framework structures and catalytic performance in Fischer–Tropsch synthesis process

Abstract

Two typical metal–organic frameworks (MOFs), i.e. tris(pyridine-2-carboxylato)-cobalt(III) monohydrate (MOF-1) and (μ2-pyridine 2,6-dicarboxylato)(pyridine 2,6-dicarboxylato) pentaaqua dicobalt(II)dihydrate (MOF-2) were employed for preparation of cobalt Fischer–Tropsch catalysts. Both MOF-derived catalysts were obtained by direct pyrolysis in N2 atmosphere at 500 °C. The pyrolysis of desired MOFs resulted nanoparticles embedded in the porous carbon matrix. Such catalysts can serve as useful catalysts for FT synthesis. Co-MOF-1 derived catalyst exhibited carbon monoxide conversion of 74.8% and selectivity towards long-chain hydrocarbons (C5+) of 49.2%. Also, it showed selectivity for short-chain hydrocarbons (C2–C4) of 36.19% for 50 h on steam while Co-MOF-2 derived catalyst displayed CO conversion of 81.6% and selectivity for long-chain hydrocarbons (C5+) and short-chain hydrocarbons of 56.8% and 28.2%. The superb activity and catalytic efficiency can be ascribed to the MOF precursors structures. This study investigated the relationship between MOF structure and catalytic performance and presented a new approach to design novel super active catalysts with preferable selectivity for Fischer–Tropsch synthesis by opting the suitable MOF precursors.


Datum: 01.10.2019


Photocatalytic discoloration of an azo-dye using LaMn 0.5 Ti 0.5 O 3 double perovskite under visible light irradiation and enhancement of photocatalytic activity by using graphene

Abstract

In this study, rare-earth perovskite-type oxides LaTiO3±δ, LaMnO3 and LaMn0.5Ti0.5O3 were prepared by the sol–gel method and tested for the photocatalytic decomposition of an azo dye, basic red 46, under visible light. The experimental results showed that the photocatalytic activity of LaMn0.5Ti0.5O3 was much higher than that of LaMnO3 and LaTiO3±δ. Then, the discoloration efficiency of basic red 46 was studied over LaMn0.5Ti0.5O3 prepared by several methods. The structure, morphology and light absorption of prepared samples were characterized by XRD, SEM and UV–vis (DRS mode) spectroscopy. The best photocatalytic performance exhibited by the LaMn0.5Ti0.5O3 prepared using the Pechini sol–gel method and its excellent activity results from narrower band-gap energy, smaller particles size and porosity structure which is capable of supporting the enhanced loading of organic contaminants on surface. In the following, graphene/LaMn0.5Ti0.5O3 nanocomposite photocatalysts were synthesized for the first time. The photocatalytic efficiency of the graphene/LaMn0.5Ti0.5O3 nanocomposites was higher than that of pristine LaMn0.5Ti0.5O3 and graphene(50%wt)/LaMn0.5Ti0.5O3 had the greatest photocatalytic activity (degradation 90% after 5 h). The excellent photocatalytic activity can be attributed to the high separation efficiency of photoinduced electron–hole pairs resulting from the excellent conductivity of in graphene/LaMn0.5Ti0.5O3.


Datum: 01.10.2019


Citronellal cyclisation to isopulegol over micro-mesoporous zsm-5 zeolite: effects of desilication temperature on textural and catalytic properties

Abstract

In this work, desilication reassembly post treatment process was applied in synthesis of mesoporous zeolite with stable phase composition and applied it in citronellal cyclisation reaction for the production of isopulegol. The desilication and temperature effects were further investigated on physical and chemical characteristics of zeolite and compared them with catalytic activity. The desilicated zeolite samples have been characterized with the help of N2-adsorption, XRD, ICP-OES, pyridine adsorption and FTIR techniques. Its performance was explored by controlling operative parameters. Experimental outcomes exhibited that desilication of zeolite would led to formation of mesopores inside the stable zeolite framework structures without substantial damage of their internal composition. These changes facilitate mass transfer and catalytic activity with an increase in surface area, mesoporosity, pore size, pore volume, acidity, and Lewis acid sites. Optimum desilication temperature (80 °C) was found as a best for an comprising extra active and selective mesoporous zeolite catalyst for citronellal cyclisation. Thus, this type of zeolite material has shown 100% conversion (e.g. complete conversion of citronellal reactants to the desired products), 95% isopulegol selectivity and highest reaction rate (0.11 min−1). This study exhibits the mesoporous zeolite (MZ-80 °C) as one of the most effective catalyst for citronellal cyclization reaction based on assessment of catalytic performance relative to other commonly available options.


Datum: 01.10.2019


Enhanced CO oxidation and toluene oxidation on CuCeZr catalysts derived from UiO-66 metal organic frameworks

Abstract

In this work, several MxOy-supported ZrO2 (MxOy = CuO, CeO2, CuO-CeO2) catalysts were prepared through the direct decomposition of metal organic frameworks UiO-66 in air. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), N2 adsorption–desorption isotherms and H2-temperature programmed reduction (H2-TPR). The catalytic performance for CO oxidation and toluene oxidation over Zr based catalysts was investigated. Amongst the prepared catalysts, CuCeZr catalyst displayed excellent CO oxidation and toluene oxidation performance. The addition of Cu was favorable to the enhancement of catalytic performance. Importantly, the addition of cerium led to the formation of easily reducible surface copper species, consequently improving the CO oxidation and toluene oxidation performance.


Datum: 01.10.2019


Cerium modification for improving the performance of Cu-SSZ-13 in selective catalytic reduction of NO by NH 3

Abstract

A series of Ce-Cu-SSZ-13 catalysts were synthesized by the ion exchange method based on the Cu-SSZ-13 prepared via a one-pot method and investigated for the selective catalytic reduction by NH3. Compared with Cu-SSZ-13, the catalytic activity and sulfur resistance of Ce-Cu-SSZ-13 were enhanced by modifying with cerium. XRD, N2-BET, MP-AES, XPS, H2-TPR and in situ DRIFTS were carried out to characterize the catalysts. XPS results suggested that more active sites on the surface of Ce-Cu-SSZ-13 catalysts. H2-TPR showed that the redox capacity of the Cu-SSZ-13 catalyst was enhanced after doping with Ce. In situ DRIFTS results demonstrated that the synergistic effect existing between copper and cerium species enhanced the adsorption performance of NH3 and NO + O2 on the catalyst surface. All of the above factors played important roles for achieving the high NH3-SCR performance.


Datum: 01.10.2019


Zinc oxide modified HZSM-5 as an efficient acidic catalyst for hydrogen production by steam reforming of dimethyl ether

Abstract

The parent HZSM-5 was modified with a series content of ZnO via the incipient impregnation method by using Zn(NO3)2·6H2O as a precursor. And the ZnO-modified HZSM-5 physically mixed with a commercial Cu/ZnO/Al2O3 was investigated as a bifunctional catalyst for steam reforming of dimethyl ether (DME). The samples were systematically characterized by XRD, FT-IR, N2 adsorption–desorption at low temperature, and NH3-TPD techniques. It was found that the introduction of ZnO would slightly influence the structure and crystallinity of the parent HZSM-5. Furthermore, the type (Lewis and Brønsted acid) and distribution (strong and weak acid sites) of acid could be adjusted by altering the content of ZnO, which took responsible for the DME conversion, H2 yield, and selectivity of the carbon-containing products. As a result, an efficient catalyst for steam reforming of DME was obtained by adjusting the content of ZnO.


Datum: 01.10.2019


Preparation of highly selective and stable Cu–Mg–Fe catalyst and its catalytic performance for one-step synthesis of 2-ethylhexanol from n -butyraldehyde

Abstract

A Cu–Mg–Fe catalyst was prepared by a coprecipitation–impregnation method and some influential factors such as Cu/Fe molar ratio, Mg/Fe molar ratio, calcination temperature and reduction temperature were investigated by means of XRD, XPS, NH3(or CO2)-TPD, H2-TPR and SEM analyses. Suitable preparation conditions were obtained as follows: a Cu/Mg/Fe ratio of 1:2:1, a calcination temperature of 550 °C, and a reduction temperature of 450 °C. The Cu–Mg–Fe catalyst showed a high catalytic performance for one-step synthesis of 2-ethylhexanol from n-butyraldehyde; the yield and selectivity of 2-ethylhexanol were 68.6% and 72.4% while the overall selectivity of C8 + C4 products was greatly improved to 96.9% under suitable reaction conditions.


Datum: 01.10.2019


Exceptional catalytic performance of Au–Pt/γ-Al 2 O 3 in naphtha reforming at very low Au dosing levels

Abstract

The catalytic behavior of Au–Pt bimetallic nanoparticles supported on γ-Al2O3 for the reforming reaction of a real desulfurized medium naphtha feed has been investigated. Composite catalysts containing 0.7 wt% metal(s) with Au/Pt weight ratios of 0:100, 1:99, 5:95, and 50:50 have been studied. XPS analysis showed that the ratio of 1:99 results in a distinct positive character of Pt in the Au–Pt nanoalloy. We show for the first time that through colorimetric analysis that the catalyst synthesized with the Au/Pt ratio of 1:99 exhibits clear surface plasmon resonance effects under visible light at 570 nm, peculiar to the electronic configuration supported by the XPS analysis. Naphtha reforming catalytic tests were performed in a WHSV range of 2–6 h−1, at 485 °C. The pressure was 5 bar, typical for continuous catalytic reforming processes. The Au/Pt ratio of 1:99 resulted in a distinct performance, i.e. maximum naphthenes conversion, maximum aromatics production and least production of benzene and hydrocarbons with a carbon number equal or less than 5. This was attributed to the formation of near-surface Au–Pt alloy with an Au mono-sublayer in the presence of H2 during the reaction. The optimal catalyst exceptionally favors dehydrogenation/dehydrogenation over hydrogenolysis reactions.


Datum: 01.10.2019


 


Category: Current Chemistry Research

Last update: 03.04.2018.






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