Pawel Mierczynski

The Effect of ZnAl2O4 on the Performance of Cu/ZnxAlyOx+1.5y Supported Catalysts in Steam Reforming of Methanol

This paper demonstrates the benefit of using spinel (ZnAl2O4) as a support for copper catalysts in hydrogen generation. We have investigated the influence of catalyst pre-treatment, support composition and copper content on the physicochemical and catalytic properties of copper catalysts supported on ZnxAlyOx+1.5y in the methanol steam reforming. The physicochemical properties of the catalysts were examined by X-ray diffraction, temperature-programmed reduction, specific surface area and porosity, X-ray photoelectron spectroscopy, FTIR and chemisorption methods. The reduced copper catalysts showed higher conversion of methanol and higher hydrogen production. We also found that the presence of Cu+ and Cu0 species on the catalyst surface strongly influences the reaction yield and hydrogen production. FTIR measurements performed for copper catalysts confirmed that increasing of aluminium content in the case of catalytic systems caused the growth of adsorbed species on the catalyst surface.

Comparative studies of Pd, Ru, Ni, Cu/ZnAl2O4 catalysts for the water gas shift reaction

AbstractThe activity of monometallic Pd, Ru, Ni and Cu catalysts supported on spinel ZnAl2O4 for water gas shift reaction (WGS) was investigated. The physicochemical properties of each catalyst was studied by XRD, TPR, BET and chemisorption methods. The highest activity was obtained for Cu/ZnAl2O4 among the catalysts tested. The activation process carried out in a reducing atmosphere 5%H2-95%Ar in the case of Cu/ZnAl2O4 system lead to the catalytic activity improvement. In the case of copper catalysts, the water gas shift reaction proceeded by the redox surface mechanism between Cu0/Cu+. The PdZn alloy formation after reduction at 350°C was shown.

The effect of gold on modern bimetallic Au–Cu/MWCNT catalysts for the oxy-steam reforming of methanol

Copper and gold doped copper catalysts supported on multi-walled carbon nanotubes were prepared by wet impregnation and deposition–precipitation methods, respectively. The catalysts were tested in the oxy-steam reforming of methanol (OSRM) and characterized by XRD, SEM-EDS, TOF-SIMS, thermo-gravimetric analysis and temperature-programmed desorption of ammonia. The reactivity results showed the promotion effect of gold on the activity and selectivity of the copper catalysts in the OSRM. The formed Cu–Au alloy as an active phase was responsible for the activity and selectivity improvement of the bimetallic catalysts in the oxy-steam reforming of methanol. The formation of an Au–Cu alloy was confirmed by the XRD, TOF-SIMS and SEM-EDS techniques. The reducibility and acidity of the tested catalysts are important factors, which influence the activity of the copper and gold–copper catalysts.

Novel Pd–Cu/ZnAl2O4–ZrO2 Catalysts for Methanol Synthesis

Monometallic Cu and bimetallic Pd–Cu catalysts promoted by ZrO2 were prepared using impregnation method. The physicochemical properties of catalytic systems were investigated using BET, scanning electron microscopy–energy dispersive spectrometry, temperature programmed reduction-H2, X-ray diffraction, Fourier transform infrared techniques. Catalytic activity was studied in fixed bed reactor under high pressure (4.8 MPa). The results show that addition both Pd and ZrO2 increases the methanol yield. Zirconium oxide improved the dispersion and reducibility of the copper catalysts. The presence of adsorption species attributed to b-HCOO–Zr, b-HCO3–Zr, m-CO3–Zr species on the surface of ZrO2 promoted catalysts was confirmed. The high activity of promoted palladium catalysts is explained by synergistic effect between Pd and Cu.Graphical Abstract

MWCNTs as a catalyst in oxy-steam reforming of methanol

The catalytic activity of multi-walled carbon nanotubes (MWCNTs) in oxy-steam reforming of methanol (ASRM) was investigated for the first time. We demonstrate that CNTs are a potent catalytic material for hydrogen generation in oxy-steam reforming of methanol.

The influence of Pd loading on the physicochemical properties of the Cu–Cr–Al methanol synthesis catalysts

This paper demonstrates the benefit of using a ternary Cu–Cr–Al system as a support for palladium catalysts in the methanol synthesis reaction (MS) obtained from CO hydrogenation. The influence of ternary oxide composition and palladium addition on the physicochemical and catalytic properties of Pd/Cu–Cr–Al catalysts in methanol synthesis is discussed. The physicochemical properties of the studied systems were examined by XRD, TPR and BET methods. The promotion effect of palladium on the catalytic activity and reduction of ternary oxide was proven. It was found that palladium promoted catalysts prepared from palladium nitrate precursor showed higher yield in methanol formation.

Comparative Studies of Bimetallic Ru–Cu, Rh–Cu, Ag–Cu, Ir–Cu Catalysts Supported on ZnO–Al2O3, ZrO2–Al2O3 Systems

This paper interrogates the catalytic properties of monometallic copper and various bimetallic Ru–Cu, Rh–Cu, Ag–Cu, Ir–Cu catalysts supported on binary oxide ZrO2–Al2O3 or ZnO–Al2O3 in oxy-steam reforming of methanol reaction. X-ray diffraction, specific surface area and porosity, temperature programmed reduction and temperature programmed desorption were used to characterize monometallic and bimetallic copper supported catalysts. The promoting effect of noble metals on reducibility and catalytic properties of copper catalyst was proven. The activity results showed that rhodium doped copper catalysts supported on ZnO–Al2O3 exhibited the highest conversion of methanol and a high selectivity towards main products of the reaction demonstrating its potential application in fuel cell technology.Graphical Abstract

Promoted ternary CuO-ZrO2-Al2O3 catalysts for methanol synthesis

AbstractTernary CuO-ZrO2-Al2O3 catalysts promoted by palladium or gold were prepared and tested in CO hydrogenation reaction at 260°C under elevated pressure (4.8 MPa). The promotion effect of palladium or gold addition on the physicochemical and catalytical properties of CuO-ZrO2-Al2O3 catalysts in methanol synthesis (MS) was studied. The catalysts were characterized by BET, XRD, TPR-H2, TPD-NH3 methods. The BET results showed that the ternary system CuO-ZrO2-Al2O3 had the largest specific surface area, cumulative pore volume and average pore size in comparison with the promoted catalysts. The yield of methanol can be given through the following sequence: 5%Pd/CuO-ZrO2-Al2O3 > CuO-ZrO2-Al2O3 > 2%Au/CuO-ZrO2-Al2O3. We also found that the presence of gold or palladium on catalyst surface has strong influence on the reaction selectivity. The high selectivity of gold doped ternary catalyst is explained by the gold-oxide interface sites created on the catalyst surface and the acidity of those systems. The higher selectivity to methanol in the case of the palladium catalyst is explained by the spillover effect between Pd and CuO.

Photocatalytic Degradation of an Azo Dye over Novel Monometallic Copper Catalysts Supported on Fibreglass

The monometallic copper catalysts were synthesized by impregnation of fibreglass material covered by TiO2 using magnetron sputtering method at a low temperature plasma technique in vacuum camera. Their physicochemical properties were extensively studied by BET, TPR-H2 and XRD techniques. The photocatalytic properties in degradation of an azo dye were controlled by determination of chemical oxygen demand, total organic carbon and using UV–VIS technique. Fibreglass covered with TiO2 and copper oxides has shown remarkable photocatalytic properties in degradation of Reactive Violet 2 dye. Its stability was increased by its preliminary treatment in HCl. The optimal content of Cu appeared to be 5% in the oxide layer of the catalyst digested in HCl. Kinetic constants determined for the process of the dye photodegradation over Cu2O (5%)/TiO2/fibreglass catalyst were one order higher than for TiO2/fibreglass.Graphical Abstract

Magnetic separation technology: Functional group efficiency in the removal of haze-forming proteins from wines

Magnetic nanoparticles were modified by plasma polymerization, using allylamine, acrylic acid and 2-methyl-2-oxazoline as precursor to produce amine, carboxyl and oxazoline functional group rich surfaces. The nanoparticles were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and zeta potential measurements. The capacity of nanoparticles carrying different surface properties to remove haze-forming proteins from Sémillon and Sauvignon Blanc unfined wines was examined by high-performance liquid chromatography (HPLC). The protein capture efficiency of the modified surfaces decreases in the following order: COOH > POx > NH2. This study will help optimising the design of this new technology for the selective removal of haze proteins from white wines.