Pd Molar Ratio Research Articles

Optimized bimetallic ratios for durable membrane catalyst-film reactors in treating nitrate-polluted water

Nitrate contamination of surface and ground water is a significant global challenge. Most current treatment technologies separate nitrate from water, resulting in concentrated wastestreams that need to be managed. Membrane Catalyst-film Reactors (MCfR), which utilize in-situ produced nanocatalysts attached to hydrogen-gas-permeable hollow-fiber membranes, offer a promising alternative for denitrification without generating a concentrated wastestream. In hydrogen-based MCfRs, bimetallic nano-scale catalysts reduce nitrate to nitrite and then further to di-nitrogen or ammonium. This study first investigated how different molar ratios of indium-to-palladium (In:Pd) catalytic films influenced denitrification rates in batch-mode MCfRs. We evaluated eleven In-Pd bimetallic catalyst films, with In:Pd molar ratios from 0.0029 to 0.28. Nitrate-removal exhibited a volcano-shaped dependence on In content, with the highest nitrate removal (0.19 mgNO3−-N-min−1 L−1) occurring at 0.045 mol In/mol Pd. Using MCfRs with the optimal In:Pd loading, we treated nitrate-spiked tap water in continuous-flow for >60 days. Nitrate removal and reduction occurred in three stages: substantial denitrification in the first stage, a decline in denitrification efficiency in the second stage, and stabilized denitrification in the third stage. Factors contributing to the slowdown of denitrification were: loss of Pd and In catalysts from the membrane surface and elevated pH due to hydroxide ion production. Sustained nitrate removal will require that these factors be mitigated.

Bimetallic Pd‐Sn Catalytic Electrodes from Deep Eutectic Solvents for Selective Nitrate Reduction Toward Nitrogen

AbstractNitrate is one of the most widespread water contaminants globally. Nitrate levels in groundwater and surface water can rise to unhealthy levels as a result of nitrogen fertilizer runoff from lawns and farms. This research aims to selectively convert nitrate to gaseous nitrogen using Palladium‐Tin (Pd‐Sn) bimetallic electrodes electrodeposited on stainless‐steel (SS). Inductively coupled plasma optical emission spectrometry, scanning electron microscope, and X‐ray diffraction are used to analyze the composition, surface morphology, and crystal structure of the electrodes. The XRD analysis reveals that the Pd‐Sn/SS electrode has a crystalline nature when a Pd molar ratio >0.5 while an amorphous phase is detected over a Pd molar ratio (≤0.5). The electrochemical nitrate reduction is carried out in a 0.1 M HClO4 / 8 mM NaNO3 solution for 5 h using electrodes prepared in deep eutectic solvent (DES) system. The Pd0.93Sn0.07/SS electrode shows the best catalytic performance in terms of high nitrate conversion of 97%, N2 selectivity of 88%, and N2 yield of 86% compared to counter electrodes. These findings demonstrate a considerable impact of the electrode preparation process on nitrogen conversion, selectivity, and yield.

Lignin-coordinated highly dispersed Pd[sbnd]Zn alloy nanocluster supported on N-doped nanolayer carbon and its application in hexavalent chromium detoxification

As a renewable and low-cost biomacromolecule with high aromaticity and carbon content, lignin is a promising raw material for preparation of versatile carbon materials. Herein, we present a facile one-pot approach to prepare PdZn alloy nanocluster catalysts supported on N-doped lignin-derived nanolayer carbon through facile pyrolysis of melamine-mixed lignin-Pd-Zn complex. The dispersion of the PdZn alloy nanoclusters could be effectively modulated by varying the addition of melamine and the molar ratio of Pd and Zn salts. PdZn alloy nanocluster catalysts (Pd-Zn29@N10C) with ultra-small particle size (about 0.47 nm) were prepared when 10 times of melamine (relative to lignin weight) was added and the molar ratio of Pd and Zn salts was 1:29. Thereby, the catalyst presented superior catalytic activity for reduction of Cr(VI) to harmfulless Cr(III), significantly better than the two references Zn@N10C (without Pd addition) and Pd-Zn29@C (without N doping), as well as the commercial Pd/C. In addition, thanks to the strong anchoring of the PdZn alloy on the N-doped nanolayer support, the Pd-Zn29@N10C catalysts also exhibited good reusability. Consequently, the current study provides a straightforward and feasible method for producing highly dispersed PdZn alloy nanoclusters by lignin coordination, and further demonstrates its excellent applicability in hexavalent chromium reduction.

FORMACIÓN DE NANOPARTÍCULAS DE PALADIO POR EL MÉTODO DE LOSPOLIOLES: INFLUENCIA DE LAS CONDICIONES ALCALINAS

The effect of sodium hydroxide (NaOH) on the size of palladium (Pd) nanoparticles obtained by the simple polyol route was studied. Nanoparticles were synthesized at room temperature using palladium(II) chloride (PdCl2) and NaOH dissolved in ethylene glycol (EG) as reduction reaction promoters. No protective agents or stabilizers were used. We monitored the reaction kinetics and the growth of the nanoparticles by UV-vis spectroscopy and their crystallinity by powder X-ray diffraction (XRD) as a function of NaOH concentration. Crystallite size was evaluated from the diffraction pattern. We found that nanoparticle growth is strongly influenced by the NaOH: Pd molar ratio. Crystallite sizes from 2 to 24 nm were obtained for molar ratios ranging from 1 to 33. At lower concentrations of NaOH, the nucleation and growth process of the nanoparticles were found to be controlled by the reduction of the Pd ion precursors.At higher concentrations, the intermediate reduction of Pd-Cl-OH species determines the nanoparticle growth rate resulting in the formation of the smallest final-size nanoparticles.

Ag-Pd alloy decorated ZnIn2S4 microspheres with optimal Schottky barrier height for boosting visible-light-driven hydrogen evolution

• Ag-Pd alloy/ZnIn 2 S 4 microspheres were achieved by a chemical reduction method. • Ag-Pd alloy loading enhanced light-absorption and charge separation of ZnIn 2 S 4 . • Ag-Pd/ZIS composites showed the excellent photocatalytic H 2 evolution performance. • Appropriate Schottky barrier height benefited the charge carrier separation. • Theoretical calculation and experimental verification confirmed optimal Ag-Pd alloy. Rapid charge carrier recombination rate and insufficient light harvesting capacity are two dominating drawbacks encountered in zinc indium sulfide (ZnIn 2 S 4 ) for photocatalytic applications. Herein, a chemical reduction method was performed to combine bimetallic Ag-Pd alloy nanoparticles (NPs) with spherical-like ZnIn 2 S 4 (ZIS). By optimizing Ag:Pd molar ratio and overall loading amount, the optimal Ag 0.25 Pd 0.75 -ZIS sample exhibited a maximum H 2 evolution rate (125.4 µmol/h) under visible light, which was higher than that of ZIS, Ag-ZIS and Pd-ZIS. The loading of Ag NPs contribution to PHE reaction by its plasmonic effect was negligible compared to that of Pd loading (Schottky effect). The apparent quantum yield (AQY) values over Ag 0.25 Pd 0.75 -ZIS sample could reach up to 18.3% at 400 nm and 15.8% at 420 nm. The enhanced activity for photocatalytic hydrogen evolution (PHE) over Ag 0.25 Pd 0.75 -ZIS sample was mainly due to the bimetallic synergistic effect that presented as follows. Firstly, the plasmon hybridization by loading Ag-Pd bimetallic alloy can significantly increase light harvesting capacity of ZIS. Secondly, the optimal Schottky barrier height formed between Ag-Pd alloy and ZIS interface was beneficial for prolonging electron-hole pair lifetimes, promoting charge carrier separation and thus facilitating PHE efficiency. Density functional theory (DFT) analysis indicated that the adsorption energy of H* over Pd 0.75 Ag 0.25 alloy was very close to zero and thus theoretically possessed the highest activity for H 2 evolution, which is in line with experimental results. Combined theoretical calculation with experimental results, a reasonable photocatalytic mechanism was proposed and verified.

Improvement of electrocatalytic alcohol oxidation by tuning the phase structure of atomically ordered intermetallic Pd-Sn nanowire networks

Atomically ordered intermetallic compounds (OICs) have aroused remarkable interests for wide applications and are considered as very promising materials for electrocatalysis owing to the strict stoichiometry, well-defined atom binding environment, and the specific crystalline phase. However, the tunable synthesis of the intermetallics remains a giant challenge. Herein, this study reports the preparation of the Pd-Sn OICs composed of an interconnected nanowire network structure with adjustable molar ratios of elements Pd and Sn. The co-reduction of Pd(acac)2 and SnCl2·2H2O in ethylene glycol (EG) in the presence of sodium hypophosphite (NaH2PO2) as the reducing agent affords OICs of three phases: hexagonal Pd3Sn2-P63/mmc, orthorhombic PdSn-Pnmb, and orthorhombic PdSn2-Aba2. Also, the pure phase can convert to two mixed phases (Pd3Sn2/PdSn and PdSn/PdSn2) by just altering the feed ratio. It is found that orthorhombic PdSn-Pnmb OIC has a large electrochemically active surface area (ECSA), excellent electrocatalytic performance (4857 mA mgPd−1), and outstanding stability toward ethanol oxidation reaction (EOR), which could be attributed to its optimal electronic structure. These results demonstrate that the phase engineering of OICs with desired components is an excellent way for catalysts design.

In-situ synthesis of nickel/palladium bimetal/ZnIn2S4 Schottky heterojunction for efficient photocatalytic hydrogen evolution

Coupling with bimetallic nanoparticles (NPs) has been considered as a promising strategy to enhance photocatalytic hydrogen evolution (PHE) efficiency of semiconductor photocatalysts and simultaneously minimize the use of expensive noble metals. Herein, we firstly synthesized spherical-like ZnIn2S4 (ZIS) by a solvothermal method, and then combined with nickel/palladium (denoted as NiPd) bimetallic NPs to form NiPd bimetal/ZIS Schottky heterojunction. The chemical states of NiPd NPs were confirmed in the form of NiPd bimetal rather than Ni–Pd alloy. The detailed characterization results demonstrated that the deposition of NiPd bimetal played a major role in increasing light harvesting capacity, accelerating charge carrier (electrons and holes) separation and facilitating photogenerated electrons transfer, leading to the boosted PHE performance in NiPd-ZIS photocatalysts. By adjusting Ni:Pd molar ratio in NixPdy-ZIS photocatalysts, the desired sample of Ni3Pd7-ZIS exhibited the highest PHE efficiency (106.6 µmol/h) and apparent quantum yield (AQY) value of 40.22% at 400 nm under visible light as compared to ZIS, Ni-ZIS and Pd-ZIS. The multiple techniques were performed to deeply investigate the photogenerated charge carrier separation, transfer and recombination. The possible mechanism over Ni3Pd7-ZIS sample for boosting PHE performance was presented based on characterization results. On the whole, this work would provide some insights into the development of cost-effective and high-efficiency bimetallic cocatalyst-based photocatalysts.

Selective precipitation of ammonium hexachloropalladate from leaching solutions of cemented palladium with zinc

Palladium (Pd) present in spent electroplating solutions is concentrated by cementation with zinc (Zn) metal powder. Therefore, it is necessary to recover Pd from the cemented Pd. In this work, recovery of pure Pd(IV) compounds from the leaching solutions of the cemented Pd was investigated by using selective precipitation method. It was found that the existence of Pd(IV) in the aqueous solutions is critical for the precipitation with NH4Cl. Precipitation experiments of Pd(IV) from the synthetic aqua regia solution containing Pd(IV) and Zn(II) was tested. Afterwards, the optimum precipitation conditions were applied to recover Pd(IV) precipitates from the real H2SO4 and HCl leaching solutions containing NaClO as an oxidizing agent. The selective precipitation resulted in the recovery of extra pure (NH4)2PdCl6 from real leaching solutions under the conditions of 1:30 molar ratio of Pd(IV) to NH4Cl at 60oC within 30 min. The precipitation percentage of Pd(IV) from the H2SO4 and HCl solutions was over 99.9 and 98.2%, respectively. A simple hydrometallurgical process consisting of cementation, leaching, and precipitation was proposed for the recovery of pure Pd(IV) compounds from spent electroplating solution.

Bimetallic Au-Pd/α-MoO3 Catalyst with High Oxygen Vacancies for Selective Oxidation of Cinnamyl Alcohol

Supported Au-Pd nanoparticles (NPs) have been extensively studied in alcohol oxidation reactions. However, few studies use reducible metal oxides as support, which can activate oxygen molecules and boost the selectivity of the reaction. In this work, Au-Pd NPs were supported on α-MoO3 and evaluated in the selective oxidation of cinnamyl alcohol without solvent. The Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and X-ray photoemission spectroscopy (XPS) analyses showed that the catalyst is richer in oxygen vacancies than the support, being probably responsible for the stability of the NPs (average size 4.62 ± 0.15 nm) and the high conversion and selectivity for the oxidation of cinnamyl alcohol. Furthermore, experiments have shown that the Au:Pd molar ratio influences the catalytic performance and can be optimized by controlling temperature, pressure, and reaction time. The catalyst proved to be active and selective for cinnamaldehyde in short reaction times. It showed satisfactory performance at 30 min and its best activity at 1 h with 94% conversion and 87% selectivity, without loss of activity and selectivity after four runs under the same reaction conditions.

Enhanced Electrocatalytic Activity of Alloyed Palladium-Lead Nanoparticles toward Electrooxidation of Ethanol.

Although many researchers have made great efforts to pursue promising high-efficiency electrocatalysts, a formidable challenge remains for designing excellent palladium-based electrocatalysts for commercializing direct liquid fuel cells. This study reports the synthesis of bimetallic PdPb nanoparticles (NPs) via a mixed solution containing cetyl trimethyl ammonium bromide as the capping agent. Alloyed PdPb NPs are formed, where the size of the NPs increases as Pb atoms are introduced gradually. However, Pd3Pb NPs are obtained with the same molar ratio of Pd and Pb in the raw systems. Among all of the as-made NPs, Pd9Pb1 NPs exhibit superior catalytic activity (2620 mA mg-1) toward ethanol electrooxidation, 4.3 times higher than commercial Pd/C catalysts (613 mA mg-1). The overall rate of the EOR for PdPb NPs is determined, demonstrating that the electrocatalytic activity of the PdPb NPs increases at high catalytic temperatures, in high pH environments, and/or at high ethanol concentrations.

CuPd alloy decorated SnNb2O6 nanosheets as a multifunctional photocatalyst for semihydrogenation of phenylacetylene under visible light

Bimetallic alloy of CuPd nanoclusters decorated SnNb2O6 nanosheet (CuPd/SN) as a multifunctional photocatalyst has been constructed successfully. Compared with SN, CuPd/SN achieves an excellent performance for semihydrogenation of phenylacetylene under visible light irradiation. Especially, CuPd/SN with the Cu:Pd molar ratio of 3:1 exhibits the highest catalytic conversion efficiency for phenylacetylene (99.6%) with high selectivity of phenylethylene (99.4%). In situ FTIR result reveals that SN could activate phenylacetylene via a C≡C → Nb π-bonded coordination which improves the selectivity of phenylethylene. Experiment results indicate that atom Pd in alloy is responsible for dissociation H2, while Cu represses the overhydrogenation. Electrochemical measurements suggest that CuPd alloy on SN surface could greatly minimize the recombination of photogenerated electron − hole pairs. The separated electrons further facilitate the production of active H. Hydrogen spillover would transfer active H to Nb site for phenylacetylene semihydrogenation. Finally, a synergetic catalytic mechanism is deeply discussed at molecule scale. This work would provide a deep insight for designing a multifunctional photocatalyst.

The nature of modifying effect of gallium on Pd-Ga/Al2O3 catalyst for liquid-phase selective acetylene hydrogenation

The structural properties of Pd-Ga/γ-Al2O3 samples prepared from joint Pd(NO3)2 and Ga(NO3)3 solution and their catalytic properties in liquid-phase acetylene hydrogenation have been studied. Using temperature programmed reduction (TPR-H2), transmission electron microscopy (TEM), diffuse reflectance infrared Fourier transform spectroscopy of adsorbed CO (CO-DRIFTS) and X-ray photoelectron spectroscopy (XPS) it was found that an increase in the ethylene selectivity to ∼ 66–70% is explained by the modification of the electronic properties of palladium by gallium at a Ga:Pd molar ratio of 0.5 and by the formation of bimetallic Pd2Ga particles in the case of Ga:Pd = 2.

Direct production of hydrogen peroxide over bimetallic CoPd catalysts: Investigation of the effect of Co addition and calcination temperature

A series of CoPd/KIT-6 bimetallic catalysts with various Co:Pd molar ratios at different calcination temperatures were prepared and used for the direct synthesis of H2O2 from H2 and O2. These catalysts were characterized by nitrogen adsorption–desorption, low and wide-angle X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), elemental mapping and energy-dispersive X-ray (EDX) methods. It was found that the particle size, electronic interactions, morphology, and textural properties of these catalysts as well as their catalytic activity in the reaction of H2 with O2 were affected by Co addition and different calcination temperatures. Also, the results showed that while the H2O2 selectivity depends on Pd2+ species, the H2 conversion is related to Pd0 active sites. Among these catalysts, CoPd/KIT-6 calcined at 350 °C (CoPd/KIT-350 catalyst) showed the best catalytic activity with 50% of H2O2 selectivity and 51% conversion of H2.

Investigation of hydrazine electrooxidation performance of carbon nanotube supported Pd monometallic direct hydrazine fuel cell anode catalysts

In this study, carbon nanotube (CNT) supported Pd catalysts at varying Pd molar ratios are prepared via NaBH4 reduction method. Catalysts prepared for hydrazine electrooxidation are characterized via N2 adsorption-desorption measurements (BET), X-ray photoelectron spectroscopy (XPS), and transmission electron microscope (TEM). Electrochemical measurements are performed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques by CHI660E potentiostat in a three-electrode system. According to the characterization results, Pd/CNT catalysts are successfully synthesized. For 5% Pd/CNT catalyst, the average particle size and the surface area determined as 5.17 nm and 773.10 m2 g-1 via TEM and BET, respectively. Between the Pd containing (0.1-20 wt %) CNT supported catalysts prepared, 5% Pd / CNT catalyst shows the best current density as 6.81 mA cm-2 (1122.63 mA mg-1 Pd). Furthermore, 5% Pd/CNT catalyst shows littlest charge transfer resistance (Rct) compared to Pd/CNT catalysts.

Preparation of Pt/Al2O3 and PtPd/Al2O3 catalysts by supercritical deposition and their performance for oxidation of nitric oxide and propene

Pt/Al2O3 and bimetallic PtPd/Al2O3 catalysts were prepared via supercritical deposition method using supercritical carbon dioxide. The effects of Pt loading of Pt/Al2O3 and Pd addition to Pt/Al2O3 on particle size, particle size distribution (PSD) and activity for NO and C3H6 oxidation and C3H6-selective catalytic reduction (C3H6-SCR) were investigated. Pt/Al2O3 catalysts were prepared with Pt loadings of 0.6, 1.2 and 2.1 wt% and a bimetallic PtPd/Al2O3 catalyst was prepared with total metal loading of 1.4 wt% and Pt:Pd molar ratio of 1.3:1. A small fraction of the particles agglomerated after calcination at 550 °C. Around 98 % of the particles had an average particle size of ∼1 nm. The rest of the particles were larger and average size of these larger particles was ∼10 nm for monometallic catalysts and ∼6.5 nm for PtPd/Al2O3. All catalysts were found to be active for NO and C3H6 oxidation and C3H6-SCR reactions. NO oxidation performance of 1.2 wt% Pt/Al2O3 catalyst was the highest. C3H6 oxidation activity increased with increasing metal content. Light-off temperature for C3H6 oxidation shifted to higher temperature in the presence of NO, suggesting competitive oxidation of C3H6 and NO. Concentration profiles indicated that C3H6-SCR started when C3H6 conversion by oxidation reached 50 %; C3H6 was consumed both by oxidation and C3H6-SCR at higher conversions.

Enhancing electrochemical nitrate reduction toward dinitrogen selectivity on Sn-Pd bimetallic electrodes by surface structure design

Bimetallic palladium (Pd) and tin (Sn) catalysts were electrochemically deposited on stainless steel mesh support by controlling the metal deposition sequence, total electrical charge, and metal composition. Results showed that the preparation procedure affected the crystal structure of bimetallic Pd-Sn catalysts, which significantly influenced nitrate removal efficiency and dinitrogen selectivity. Electrode with Sn on the outside surface exhibited relatively greater nitrate removal rate constant and nitrate conversion. The Sn to Pd molar ratio and the electrical charge applied during electrode preparation also affected the nitrate reduction performance. The SS/Sn0.2Pd0.8-497 electrode exhibited 88, 89, 79, and 9% of total nitrate removal, dinitrogen selectivity, dinitrogen yield, and NH4+ selectivity, respectively. Among the three major facets, (214), (131) and (420) of Sn3Pd alloy on the electrode surface, (420) exhibited the most critical effect on the dinitrogen yield. Crystal structure of catalysts controls the reactivity and selectivity of electrochemical reduction as exemplified by nitrate.

High Active PdSn Binary Alloyed Catalysts Supported on B and N Codoped Graphene for Formic Acid Electro-Oxidation

A series of PdSn binary catalysts with varied molar ratios of Pd to Sn are synthesized on B and N dual-doped graphene supporting materials. The catalysts are characterized by X-ray diffraction (XRD) and Transmission electron microscopy (TEM). Formic acid electro-oxidation reaction is performed on these catalysts, and the results reveal that the optimal proportion of Pd:Sn is 3:1. X-ray photoelectron spectroscopy (XPS) measurements show that when compared with 3Pd1Sn/graphene, B and N co-doping into the graphene sheet can tune the electronic structure of graphene, favoring the formation of small-sized metallic nanoparticles with good dispersion. On the other hand, when compared with the monometallic counterparts, the incorporation of Sn can generate oxygenated species that help to remove the intermediates, exposing more active Pd sites. Moreover, the electrochemical tests illustrate that 3Pd1Sn/BN-G catalyst with a moderate amount of Sn exhibits the best catalytic activity and stability on formic acid electro-oxidation, owing to the synergistic effect of the Sn doping and the B, N co-doping graphene substrate.

Enhancing Hydrogen Evolution Reaction Activities of 2H-Phase VS2 Layers with Palladium Nanoparticles.

Effective hydrogen (H2) production with surface engineering of less active catalysts by an innovative approach is followed here. In this work, a non-noble 2H phase of VS2 layers, which showed poor activity for hydrogen evolution reaction (HER) in 0.5 M H2SO4, was made highly active by decorating palladium (Pd) nanoparticles (NPs) over VS2 layers. A density functional theory (DFT) study confirmed the successful binding of Pd with VS2, and the bond length in a Pd4 tetrahedron was measured to be 2.60 Å. In VS2-Pd, Pd as a Pd4 tetrahedron is pointed toward the VS2 layer, and the calculated Pd-S bond distance is 2.42 Å with some expansion of three Pd-Pd bonds (2.85 Å). From the density of states, it was confirmed that the band gap was too high for VS2 (0.2 eV; 2H phase) and was reduced to nearly zero in VS2-Pd (0.05 eV). In the electrocatalytic HER part, the obtained ΔGH values from DFT were 0.05, -0.45, and 0.22 eV for VS2/Pd4, Pd4, and VS2, respectively, which imply that VS2-Pd4 had improved HER activity compared to pristine VS2 and Pd4. A concentration-dependent study was carried out with molar ratios of Pd at 0.01, 0.05, and 0.1 M with VS2 layers. From the HER polarization study, VS2-Pd (0.05 M) showed an overpotential of 157 mV at 20 mA cm-2, which is 373 mV less than only VS2 with a Tafel slope of 75 mV dec-1 with overwhelming stability. These highly promising results will be interesting to make less active stable phases by incorporating metal NPs for efficient and stable H2 production.

Continuous Flow Synthesis of Bimetallic AuPd Catalysts for the Selective Oxidation of 5‐Hydroxymethylfurfural to 2,5‐Furandicarboxylic Acid

AbstractThe production of 2,5‐furandicarboxylic acid (FDCA) from the selective oxidation of 5‐hydroxymethylfurfural (HMF) is a critical step in the production of biopolymers from biomass‐derived materials. In this study, we report the catalytic performance of monometallic Au and Pd, and bimetallic AuPd nanoparticles with different Au : Pd molar ratios synthesised under continuous flow conditions using a millifluidic set‐up and subsequently deposited onto titanium dioxide as the chosen support. This synthetic technique provided a better control over mean particle size and metal alloy composition, that resulted in higher FDCA yield when the catalysts were compared to similar batch‐synthesised materials. A 99% FDCA yield was obtained with the millifluidic‐prepared AuPd/TiO2 catalyst (Au : Pd molar composition of 75 : 25) after being calcined and reduced at 200 °C. The heat treatment caused a partial removal of the protective ligand (polyvinyl alcohol) encapsulating the nanoparticles and so induced stronger metal‐support interactions. The catalyst reusability was also tested, and showed limited particle sintering after five reaction cycles.

PREPARATION AND PROPERTIES OF PT-RH-PD / CEO2-ZRO2-LA2O3-AL2O3 FIBROUS CATALYST VIA ELECTROSPINNING

In order to increase the specific surface area of Pt-Rh-Pd / Al2O3 automotive three-way catalyst and improve its low-temperature reduction performance, Ce, Zr, and La were added to the Pt-Rh-Pd / Al2O3 catalyst to prepare the fibrous Pt-Rh-Pd / CeO2-ZrO2-La2O3-Al2O3 catalyst via an electrospinning technique. The fibrous catalysts were characterized by XRD, FT-IR, SEM-EDS, H2-TPR and BET analysis. The catalytic effect of the catalyst on automobile exhaust was also studied. Results revealed that the surface of catalysts is mainly mesoporous. Ce, Zr and La can remarkably increase the specific surface area of the Pt-Rh-Pd / Al2O3 catalyst. The specific surface area of the catalyst prepared with Pt Rh Pd molar ratio of 0.75:0.01:1 is 301.5816 m2 g-1, and the average diameter of which is 790 nm. In addition, the reaction temperature of the catalyst is approximately 220 °C, which shows good low-temperature reduction performance. Moreover, the Pt-Rh-Pd / CeO2-ZrO2-La2O3-Al2O3 catalyst has a catalytic conversion efficiency for NOX of 90.0% in automobile exhaust, a catalytic conversion efficiency for CO of 88.8%, and a catalytic conversion efficiency for SO2 of 75%.