Single-atom Pd1Cun/Al2O3 catalysts were studied in frontend acetylene hydrogenation. It was found that the selectivity to ethylene increases sharply as the Pd : Cu ratio changes from 1 : 1 to 1 : 10. Single-atom PdCu/Al2O3 catalysts demonstrate remarkable resistance to CO swings and retain high selectivity in its absence, which are crucial for industrial applications.

The PdM intermetallic systems of various compositions (M = Fe, Ga, In) deposited on SiO2 were used to establish the relationship between the surface structure, phase composition of nanoparticles, and the behavior in the catalytic hydrogenation of carbon dioxide to methanol. The PdFe/SiO2 catalyst showed a high activity, but a very low methanol selectivity (2.7

The single-atom Pd catalysts based on silver-rich bimetallic compositions are known for their extremely high ethylene selectivity in the acetylene hydrogenation reaction; however, their activity is noticeably lower than that of traditional monometallic Pd catalysts. The aim of the work was to apply a method of CO-induced segregation to increase the concentration of single atom Pd-1 sites on the surface of Pd1Ag10/Al2O3 catalyst without noticeable formation of multiatomic Pd-n (n >= 2) ensembles. It has been experimentally established by DRIFTS-CO and XPS methods that the effect of 30 vol% CO exposure temperature on the increase of surface Pd-1 sites concentration in the range of 50 to 350 degrees C has a volcano-like dependence with a maximum at similar to 200-250 degrees C. The catalytic tests show a considerable enhancement in activity for samples treated in CO at 200-250 degrees C (the temperature of 100 % acetylene conversion is reduced by similar to 30 degrees C), while the C2H4 selectivity was similar for both freshly reduced and CO-treated catalysts. These results demonstrate the use of CO-induced segregation as a promising method for the controlled increase in the concentration of isolated Pd-1 sites to improve the activity of silver-rich palladium catalyst without compromising its selectivity.

It has been found that the activity of the zeolite (Fe-Beta) and oxide (V2O5–WO3/Al2O3) catalysts in the selective catalytic reduction (SCR) of NO by NH3 can be significantly improved in the temperature range of 100–250°C by introducing ozone into the gas stream entering the catalyst. The study of the temperature dependences of the reaction product composition shows that for the oxide catalyst the increase in NOx conversion occurs due to NOx reduction via “fast” SCR pathway, whereas for the zeolite catalyst the NO2-SCR pathway also makes a significant contribution.

A herein proposed PdAu/Al2O3 2 O 3 egg-shell catalyst for selective acetylene hydrogenation combines two factors to provide perfect performance: isolation of Pd1 1 active sites by Au and an egg-shell distribution of the active phase across the catalyst pellets. The PdAu/Al2O3 2 O 3 catalyst exhibits high acetylene hydrogenation activity at the level of Pd-catalysts and high intrinsic ethylene selectivity of Au-catalysts.

The PdAg/α-Al2O3 catalyst with an egg-shell distribution of single-atom alloy (SAA) Pd1Ag nanoparticles was obtained using the complex PdAg2(OAc)4(HOAc)4 as a precursor and characterized by FESEM-EDS, XPS, and DRIFTS CO analysis. The egg-shell Pd1Ag SAA catalyst demonstrated superior selectivity in the hydrogenation of acetylene in acetylene–ethylene feed.

Heterogeneous catalysts are of considerable interest for their ability to produce gases with highly polarized nuclear spins by using parahydrogen. Rh catalysts are known for producing pronounced parahydrogen-induced polarization (PHIP) effects. This study illustrates that modification of Rh with In promotes the electronic/chemical state of Rh offering the new Rh-In bimetallic catalyst, which is more efficient in such processes compared to monometallic Rh. Both catalysts were tested in hydrogenations of propyne and propylene. We associate the 50-fold higher activity of Rh-In/SiO2 in pairwise hydrogen addition compared to monometallic Rh/SiO2 with the formation of the intermetallic Rh-In compound, which was confirmed by X-ray photoelectron spectroscopy and X-ray diffraction analysis. Intermetallic Rh-In/SiO2 provided an similar to 1400-fold NMR signal enhancement for propylene in propyne hydrogenation. It was also demonstrated that the activity of Rh-In/SiO2 can be tuned by controlling the reductive/oxidative pretreatment.

The characteristics of the porous structure and the specific surface area of the support have a significant impact on both the structure of the active sites and the efficiency of catalysts for the synthesis of methanol from CO2. 2 . The use of a complex of physicochemical methods of analysis in combination with the results of catalytic experiments has enabled the main tendencies in the development of productive and selective catalysts based on PdIn intermetallic nanoparticles to be established.

The Co/BEA zeolite catalyst was found to exhibit exceptionally high activity in ozone catalytic oxidation (OZCO) of methane impurities in air, and it provided CH4 conversion >85

Egg-shell catalysts PdAg/Al2O3 with a molar ratio of Ag: Pd ranging from 0.5 to 10 were synthesized in order to study the gas-phase hydrogenation of acetylene. The results obtained by IR spectroscopy of adsorbed CO and transmission electron microscopy confirm the assumption that a catalyst with an equimolar ratio Ag: Pd = 1 contains a substitutional solid solution, while at a ratio of Ag: Pd = 10 single-atom Pd-1 sites, isolated from each other by silver atoms are formed. The results presented in this work demonstrate that the transformation of the active sites from the substitutional solid solution structure to the single-atom arrangement entails a considerable increase in selectivity toward the formation of ethylene.

A herein proposed PdAu/Al2O3 egg-shell catalyst for selective acetylene hydrogenation combines two factors to provide perfect performance: isolation of Pd1 active sites by Au and an egg-shell distribution of the active phase across the catalyst pellets. The PdAu/Al2O3 catalyst exhibits high acetylene hydrogenation activity at the level of Pd-catalysts and high intrinsic ethylene selectivity of Au-catalysts.

The study demonstrates the possibility of promoting the V2O5/SiO2 catalyst with a small amount of Co to increase its activity in the ozone-assisted catalytic oxidation (OZCO) of volatile organic compounds. It was found that the conversion of n-C4H10 over the Co-promoted V2O5/SiO2 catalyst (0.5

The use of supported intermetallic PdxIny nanoparticles as an efficient catalyst for the synthesis of methanol from carbon dioxide was shown. On catalysts with a ratio of Pd : In = 1 : 1–1 : 2 the optimal performance (rMeOH = 65.3 gMeOH kgcat−1 h−1) and methanol selectivity (SMeOH = 49.4

A series of Ag/Al2O3 catalysts with different Ag loading in a range of 0.5–10 wt

The effect of support on the performance of Pd1Ag10/Al2O3 and Pd1Ag10/CeO2–ZrO2 catalysts in the selective hydrogenation of diphenylacetylene (DPA) was studied. Characterization of the catalyst by DRIFTS-CO and HRTEM revealed the formation of a PdAg single-atom alloy (SAA) structure on the surface of PdAg nanoparticles, with Pd1 sites isolated by Ag atoms. It was found that the use of CeO2–ZrO2 as a carrier makes it possible to increase the activity of the Pd1Ag10 catalyst by a factor of three without loss of selectivity compared to the reference Pd1Ag10/Al2O3. According to the HRTEM data, this catalytic behavior can be explained by an increase in the dispersion of Pd1Ag10/CeO2–ZrO2 compared to its Pd1Ag10/Al2O3 counterpart. As evidenced by DRIFTS-CO data, the high selectivity of the Pd1Ag10/CeO2–ZrO2 sample presumably stems from the stability of the structure of isolated Pd1 sites on the surface of SAA Pd1Ag10/CeO2–ZrO2.

The transformations of chemical states and structures occurring in the PdIn/Al2O3 catalyst upon redox treatments in different gaseous atmospheres at different temperatures are addressed by an assortment of in situ bulk- (XRD) and surface-sensitive (XPS and DRIFTS CO) techniques. Any desired state of the catalyst between two opposite extremes of highly dispersed oxide species and regularly ordered PdIn intermetallic compound could be set in fully controlled and reversible ways by selecting appropriate conditions for the reductive treatment starting from the fully oxidized state. Since mutual conversions of multi-atomic Pdn centers into single-site Pd-1 centers are involved in these transformations, the methodology could be used to find an optimum balance between the activity and selectivity of the catalytic system.

The study investigates the potential for promoting V2O5/Al2O3 catalysts for selective catalytic reduction of nitrogen oxides with ammonia (NH3-SCR). It was found that the activity of low-V2O5 (2–4 wt %) catalysts can be markedly enhanced (by a factor of 3–4) by their promotion with tungsten oxide. It was shown that a promoted V–W/Al2O3 catalyst that contains 4 wt % of V2O5 can achieve a NOx decomposition efficiency of 90% or even higher in the range of 360–500°C at a GHSV above 100,000 h–1

The study investigates the potential for promoting V 2 O 5 /Al 2 O 3 catalysts for selective catalytic reduction of nitrogen oxides with ammonia (NH 3 -SCR). It was found that the activity of low-V 2 O 5 (2–4 wt %) catalysts can be markedly enhanced (by a factor of 3–4) by their promotion with tungsten oxide. It was shown that a promoted V–W/Al 2 O 3 catalyst that contains 4 wt % of V 2 O 5 can achieve a NO x decomposition efficiency of 90% or even higher in the range of 360–500°C at a GHSV above 100,000 h –1 .

A dual-zone catalytic systems 10%Mn/Al 2 O 3 ||10%Ag/Al 2 O 3 has been developed for the low temperature light alkanes oxidation in presence of ozone. The upstream bed (10%Mn/Al 2 O 3 ) is responsible for the ozone catalytic oxidation (OZCO) of light alkanes, while the downstream bed (10%Ag/Al 2 O 3 ) provide effective carbon monoxide abatement and O 3 -slip decomposition. The system demonstrates effective removal of hydrocarbons at 100 °C for a long time.

The use of conventional co-impregnation methods makes it possible to synthesize supported PdxIny nanoparticles with defined stoichiometry, which is determined by the ratio of components during the preparation stage. The phase composition and surface structure of the intermetallic nanoparticles is determined using FTIR-CO, TEM, and XRD analysis.