CO2 Hydrogenation to Synthetic Natural Gas over Ni, Fe and Co–Based CeO2–Cr2O3

CO2 methanation was studied over monometallic catalyst, i.e., Ni, Fe and Co; on CeO2-Cr2O3 support. The catalysts were prepared using one-pot hydrolysis of mixed metal nitrates and ammonium carbonate. Physicochemical properties of the pre- and post-exposure catalysts were characterized by X-Ray Powder Diffraction (XRD), Hydrogen Temperature Programmed Reduction (H2-TPR), and Field Emission Scanning Electron Microscope (FE-SEM). The screening of three dopants over CeO2-Cr2O3 for CO2 methanation was conducted in a milli-packed bed reactor. Ni-based catalyst was proven to be the most effective catalyst among all. Thus, a group of NiO/CeO2-Cr2O3 catalysts with Ni loading was investigated further. 40 % NiO/CeO2-Cr2O3 exhibited the highest CO2 conversion of 97.67% and CH4 selectivity of 100% at 290 °C. The catalytic stability of NiO/CeO2-Cr2O3 was tested towards the CO2 methanation reaction over 50 h of time-on-stream experiment, showing a good stability in term of catalytic activity.

Bimetallic Co and Mn Supported on Hydroxyapatite Catalyst for Carbon Monoxide Oxidation at Lower Temperature

The series of bimetallic Co and Mn supported on hydroxyapatite catalyst were prepared by successive deposition method and examined for CO oxidation. The CO oxidation activity was compared with monometallic Mn/HAp and Co/HAp. The catalysts are characterized in detail and correlated to the oxidation activity. The XRD, XPS and TPR characterization showed the presence of more facile Co2+, Mn3+ and adsorbed oxygen due to the interaction between Mn and Co. The 0.4 mol Mn and 0.1 mol Mn deposited on HAp showed formation of maximum active species. The maximum CoO species was observed over bimetallic catalyst compared to the monometallic catalyst. These active lower the activation energy require for CO and oxygen. These species were responsible for the oxidation of CO at lower temperature compared to the remaining catalyst.

Self-supported cobalt-nickel bimetallic telluride as an advanced catalyst for oxygen evolution reaction

Compared with a monometallic catalyst, nanostructured bimetallic catalysts present an enhanced electrocatalytic performance due to the synergistic effect of two metal elements. To improve the OER performance of metal tellurides,...

Tuning CO Binding Strength via Engineering Copper/Borophene Interface for Highly Efficient Conversion of CO into Ethanol

Copper is currently the most active monometallic catalyst to generate hydrocarbon and oxygenated products, while the huge kinetic barrier for the formation of C-C bond on the path toward the...

BUTENEDIOLS PRODUCTION FROM ERYTHRITOL ON Rh PROMOTED CATALYST

The C-O hydrogenolysis of Erythritol to Butanodiols was studied in aqueous solution at 473 K and 25 bar of H2 using Rh/ReOx/TiO2 and the monometallic Rh/TiO2 and ReOx/TiO2 catalysts. The solids were characterized by temperature programmed reduction (TPR), TEM and XPS. TPR and XPS showed that ReOx species are close to Rh particles leading to reduction at lower temperature than Re on monometallic catalyst. However, some segregated Rhenium species were suspected by TPR profile for the bimetallic catalyst and detected by TEM. Re/TiO2 exhibited low activity forming only products from dehydration and epimerization. Although Rh/TiO2 showed high activity (total conversion at 14 h), was more selective to C-C cleavage leading to lower carbon products. Rh/ReOx/TiO2, showed instead, a good activity and selectivity towards C-O hydrogenolysis route yielding 37.5% of Butanodiols. Activation energy and reaction orders on ERY (0.58) and H2 (0.53) were estimated from experiences made at different reaction conditions

Chlorobenzene hydrodechlorination on bimetallic catalysts prepared by laser electrodispersion of NiPd alloy

NiPd bimetallic systems were for the first time synthesized by laser electrodispersion (LED) of the Ni77Pd23 alloy target followed by the deposition of produced bimetallic particles on a TEM copper grid and alumina granules. Selective area energy-dispersive analysis confirms the bimetallic nature of NiPd particles deposited on a TEM copper grid. Their mean size is 1.0 nm according to TEM. XPS data demonstrate that under deposition on alumina granules (total metal content of 0.005 wt.%), nickel in bimetallic particles nearly completely oxidizes to Ni2+ species predominantly in the form of aluminate. At the same time major part of palladium (84%) exists in Pd0 but oxidizes to Pd2+ (80%) during 6 months storage in air. Both metals are deposited on the external surface of alumina granules and localized in the same areas. In situ reduction of both metals by H2 in the catalytic cell of XPS spectrometer is hindered. Nickel is not reduced even at 450°C, confirming the formation of NiAlOx, whereas palladium is reduced at higher temperatures compared to a similar monometallic catalyst. Nevertheless, NiPd/Al2O3 catalyst is more efficient in gas-phase chlorobenzene hydrodechlorination at 150–350°C than Ni/Al2O3 and even Pd/Al2O3, and much more stable. The difference may be caused by the formation of new active sites due to the contact between Pd0 and NiAlOx-modified support, and the protective action of spinel reacting with HCl by-product.

CO2 and CO hydrogenation over Ni-supported materials

This work reports on the fundamental properties of nanostructured catalysts active in the main carbon oxides’ conversion processes for sustainable energy supply: methanation and co-methanation of CO2. Transition metals (e.g. Ni, Pd, Pt, Co, Ru, Rh) are active species in both reactions. Ni has been the most studied because of its cheapness. Monometallic and bi-metallic Ni and Ni3Fe catalysts supported on Gadolinia-doped ceria (GDC) have been synthesized, characterized and tested in the temperature range 200–600[Formula: see text]C. In the methanation reaction, the monometallic catalyst showed higher performance with respect to the bi-metallic catalyst. At 400[Formula: see text]C, the CO2 conversion overcomes 90% with CH4 selectivity of 100%. In co-methanation, the highest CO2, CO and H2 conversion values over monometallic Ni/GDC catalyst were obtained at 300[Formula: see text]C; at higher temperatures, conversion decreases. The GDC support plays a pivotal role in both reactions, enhancing the basicity of the catalyst and improving the dissociation of carbon oxide species adsorbed on Ni sites.