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Two series of nanostructured carbon replicas were synthesized through a hard-templating method using ordered SBA-15 or disordered mesoporous spherical silica gel as the templates and furfuryl alcohol or sucrose as the carbon source. They were explored to synthesize the Pd catalysts (ca. 1.5 wt% Pd loading) by the colloid-based microemulsion procedure which allowed preparing the catalysts of monodispersed Pd particles of similar size (4–5 nm). The palladium phase in the catalysts (e.g. the Pd particles distribution and extent of agglomeration) varied depending on the textural and surface characteristics of the carbon replicas. In the furfural hydrogenation studied as a probe reaction (2-propanol, 35 °C, 6 bar H2), furfuryl alcohol and tetrahydrofurfuryl alcohol were the major products formed. The catalytic reactivity has been related to the properties of the Pd phase including the surface Pd concentration and the extent of the Pd particles aggregation accompanied by the nearest palladium environment expressed by the surface O/Pd atomic ratio. At high O/Pd ratio the reaction slowed down because of a facilitated furfuryl alcohol adsorption resulting most probably in a blockage of the active sites. The SiO2 sucrose system provided the catalyst which was characterized by relatively low O/Pd ratio with well-dispersed Pd particles and the highest and stable activity for the furfural hydrogenation. The SBA-series catalysts, with lower O/Pd and more aggregated Pd particles, exhibited lower activity but somewhat higher tendency to the tetrahydrofurfuryl alcohol formation.

Supported Pd/Ir bimetallic catalysts were synthesized by the “water-in-oil” microemulsion method at different precursor concentrations and characterized by XRD, XPS, SEM, TEM, and cyclic voltammetry. Depending on the preparation conditions, formation of bimetallic catalysts with different metal segregation and surface composition can be easily obtained, thus tuning the bimetallic structure of catalysts as well as their relative catalytic properties. Bimetallic Pd/Ir systems were efficiently tested in the hydrogenation of cinnamaldehyde showing a better performance than analogous monometallic catalysts.

The influence of the oxidized carbon moieties in the nanostructured carbon-supported Pd catalysts was studied for the furfural hydrogenation (2-propanol, 35 °C, 6 bar H2). The mesoporous carbon replicas synthesized using two systems: SBA-15-furfuryl alcohol or nanostructured SiO2-sucrose and oxidized with nitric acid or hydrogen peroxide were used as the supports. The catalysts (1.5–2 wt% Pd) of similar Pd particles size (ca. 4 nm) were synthesized by the “water-in-oil” microemulsion procedure. Although the carbon-supported Pd, Pt catalysts have been tested for the furfural hydrogenation, the effect of oxygenated carbon groups have not been yet investigated. Present results showed that the surface O/Pd atomic ratio influenced the rate and product distribution. Over initial carbon-supported Pd, the rate was high and apart from furfuryl alcohol and tetrahydrofurfuryl alcohol certain amount of “other” products was also observed. The oxidized carbon-supported catalysts were less active but more selective towards furan ring hydrogenation with almost completely inhibited “other” products formation reactions. The growing content of surface oxidized groups, in particular the carboxylic ones, corresponded well to the order of decreased activity. This effect has been related to a gradually reduced access of the regents to the Pd-surface sites because of the growing tendency to the hydrogen bonds formation with the participation of the oxygenated carbon groups – furfuryl alcohol – 2-propanol alcohol solvent.

The series of Cs2HPW12O40 samples was prepared using various reagents, namely Cs2CO3 and CsCl, as the precipitating agent. Moreover, the modification of preparation procedure consisting of HCl addition to the colloidal solution of Cs2HPW12O40 salt, precipitated previously with Cs2CO3 and H3PW12O40, was also studied. The aim of present research was to recognize the role of precipitating agent in the physicochemical and catalytic properties of Cs2HPW12O40 samples. The samples were characterized by number of techniques, BET, FT-IR, 31P NMR, XRD, XPS, TPD-MS, laser diffraction, NH3 sorption. It was observed that the lattice parameters and the environment of phosphorous were the same in all studied samples. The Cs2HPW12O40 salt prepared by Cs2CO3 exhibited very low specific surface area of about 1 m2/g. In contrast, the usage of CsCl yielded the sample of remarkably higher surface area (∼78 m2/g) and dramatically higher catalytic activity for dehydration of ethanol. Thus, an effect of precipitating agent can be ascribed to its influence on the size of colloidal particles formed upon preparation procedure. It has been postulated that the adsorption of HCl/chloride ions on the surface of primary particles of Cs2HPW12O40 salt facilitated the formation of mesoporous structure, which determined its sorption and catalytic properties.

Functional gel-type resin-based palladium catalysts (0.5–2 wt.% Pd) of well dispersed Pd nanoparticles were prepared and characterized by SEM, TEM techniques and swelling measurements. The role of specific properties of gel-type matrix was studied in the hydrogenation of unsaturated C C bonds in series of carboxylic acids, derivatives of acrylic acid. They differ in the type of substituents (methyl, phenyl and carboxyl groups) at the double bonded carbon atoms. The rate of hydrogenation is found to depend on the crosslinking degree of the resin and on the presence of steric hindrance around the C C bond in individual reactants. The influence of the substrate molecules size, their hydrophobicity and absolute hardness/polarizability on the rate of the C C hydrogenation has been established by theoretical modelling.

The hydrogenation of 2-ethylanthraquinone (eAQ) was performed over alumina, silica and carbon supported palladium catalysts. Present research is concentrated on the process of eAQ degradation and especially a role of the type of catalyst is examined. Degradation of eAQ in the catalytic experiments has been discussed on the basis of reaction pattern reported for the reduction of carbonyl groups in anthraquinone by standard procedures (Zn, Sn, NaBH4). Various by-products formed by degradation of hydroquinone (eAQH2) have been identified by GC–MS. They are the product of C O hydrogenolysis such as 2-ethylanthrone (eAN, two isomers), 2-ethylanthracene (eANT) and the products of eAN hydrogenation (H4eAN, two isomers). Tautomerization of partially and fully saturated hydroquinones produces OXO-isomers [two isomers OXO-H4(1,2) and OXO-H8(1,2)]. Reduction of eAQ with NaBH4 gives 2-ethyl-9,10-dihydroxy-9,10-dihydroanthraquinone, intermediate product in the consecutive reactions occurring during the hydrogenolysis of C O and resulting in eAN. A difference in performance of 0.5% Pd/C, 0.5% Pd/SiO2 and 0.5% Pd/Al2O3 catalysts is related with their reactivity in degradation of eAQH2. Much higher reactivity in the whole degradation process and especially in the formation of intermediate product exhibits alumina-supported catalyst.

The effects of the type of support and Pd concentration profile in alumina and silica supported egg-shell catalysts and their performance in the hydrogenation of 2-ethylanthraquinone (eAQ) were studied in 'Anthra' (AQ) and 'All-Tetra' systems. The activity and deactivation of catalysts were determined in the fixed-bed reactor. Solution saturated with hydrogen, (concentration of active quinones 60g/dm3, eAQ in the AQ system, 30% of eAQ and 70% of H4eAQ–2-ethlytetrahydroanthraquinone, in the All-Tetra system) was circulated through the catalyst bed at temperature 50°C and pressure 5bar. The contents of eAQ, active quinones, H4eAQ and degradation products were determined in the course of hydrogenation by GC method. The egg-shell palladium catalysts (1–2wt% Pd) prepared by the precipitation of palladium hydroxide onto alumina and silica supports pre-impregnated with various alkaline (NaHCO3, NaH2PO4, Na2SiO3) solutions were used in the hydrogenation experiments. Pd concentration profile inside the grains of catalysts was characterized by scanning electron microscopy. A difference between alumina and silica carriers with respect to the course of side reactions producing degradation products was found. Degradation of quinones in the hydrogenolytic reactions predominated on alumina supported catalysts, while the catalysts with silica favoured the hydrogenation of aromatic rings resulting in H4eAQ-active quinone. As a crucial factor for the decrease in the activity during the hydrogenation run, the reactivity of catalyst in the hydrogenolytic reactions was established. Alumina supported catalysts exhibited much higher deactivation than those of silica supported ones. Silica carrier as well as silica species introduced onto alumina under pre-impregnation with Na2SiO3 exhibited an advantageous role in the catalyst performance, in terms of activity and deactivation.

The chemical incorporation of palladium into polyaniline (PANI) deposited onto the silica gel microparticles (15-μm in diameter) was studied. The as-prepared silica particles coated with PANI–hydrochloride (AC) were treated with aqueous ammonia solution (0.1 M) to transform polyaniline to its base (BA) form. Both AC and BA samples were reacted with PdCl 2 solutions (2.3×10 −3 M) strongly differing in the concentration of HCl (0.1 M HCl, series K; 6.6×10 −4 M HCl, series Z). Two series of samples with 0.43–2.14 wt.% Pd were obtained. Fourier-transform infra red (FTIR), UV-Vis, X-ray photoelectron spectroscopies (XPS) and scanning electron microscopy have been used to examine the nature of processes involved upon insertion of Pd and to characterize palladium species in the final samples. Very similar palladium species were found in the polymer matrix independently of the acidity of PdCl 2 solutions and the extent of PANI protonation (AC and BA samples). Pd 2+ was the only form if no more than 0.86% Pd was introduced. Incorporation of higher content of palladium resulted in the partial reduction (14.6–28.7%) of Pd 2+ to Pd 0 . The presence of Pd 2+ species in the form of complexes in which besides Cl − ligands also nitrogen groups of PANI participated has been postulated. The catalytic properties of Pd/PANI-SiO 2 have been studied in the liquid-phase hydrogenation of 2-ethylanthraquinone (EAQ) at 60 °C under 1 atm of hydrogen. Very low activity of the as-prepared catalysts significantly increased due to reduction of the samples with NaH 2 PO 2 and subsequently with dihydrogen. The specific activities of reduced series K and Z samples were comparable and the maximum activity exhibited catalysts with 1–1.5% Pd.