Recent Development of Renewable Diesel Production Using Bimetallic Catalysts

Renewable diesel as a potential sustainable energy source in future requires catalysts to convert the feedstocks into end products. Among various type of catalysts, bimetallic catalysts are widely applied in the renewable diesel production due to their unique catalytic properties and enhanced catalytic activities, which differ from their parent monometallic catalysts. This mini review comprised of the brief introduction on technologies in producing renewable diesel and aims to discuss the underneath knowledge of synergistic interactions in bimetallic catalysts that synthesized through various techniques. The novelty of this review reveals the recent development of renewable diesel production, highlighting the mechanisms of bimetallic catalysts in the enhancement of the catalytic activity, and exploring their possibilities as practical solution in industrial production.

The Effect of Modifiers on the Performance of Ni/CeO2 and Ni/La2O3 Catalysts in the Oxy–Steam Reforming of LNG

This work interrogates for the first time the catalytic properties of various monometallic Ni catalysts in the oxy-steam reforming of LNG. Various research techniques, including X-ray diffraction (XRD), specific surface area and porosity analysis (BET method), scanning electron microscopy with X-ray microanalysis (SEM-EDS), temperature-programmed desorption of ammonia (TPD-NH3), temperature-programmed reduction (TPR-H2) and the FTIR method, were used to study their physicochemical properties. The mechanism of the oxy-steam reforming of LNG is also discussed in this paper. The high activity of monometallic catalysts supported on 5% La2O3–CeO2 and 5% ZrO2–CeO2 oxides in the studied process have been proven and explained on the basis of their acidity, specific surface area, sorption properties in relation to the reaction products, the crystallite size of the metallic nickel and their phase composition.

PROCESSING OF LIQUEFIED PETROLEUM GASES OVER MONO-AND BIMETALLIC CATALYSTS

The reserves of liquefied petroleum gas in the production zones and fields are briefly characterized in present paper. The scope of liquefied petroleum gases application, catalytic transformation and their importance in obtaining products are described. Widespread use of nanostructured and nanoscale catalysts in catalysis processes and their properties are given in literature review. Chemical transformations of С3-С4-alkanes in the presence of mono- and bimetallic catalysts based on Cr/SiO2 are studied. By method of electron microscopy, it was determined that various highly dispersed oxides of chromium in lanthanum – modified catalyst interact with each other and with carrier. According to electronic paramagnetic resonance data, chromium is contained in a five- and three-valence state. Mono - and bimetallic catalysts were studied by physical and chemical methods: IR spectroscopy, electron microscopy (EM) using micro diffraction, EPR. Monometallic catalysts with a chromium content of 2-10 wt. % and bimetallic lanthanum-chromium-containing catalyst in the form of 5% La-Cr/SiO2 in a ratio of 1/1 were prepared in the work; the process temperature was varied in the range of 400 to 650°С. Introduction of lanthanum leads to the formation of LaCrO3, LaCrO4 compounds with low activity in dehydro-genation reaction of C3-C4 – alkanes. The maximum yield of C2-C4-olefins - 39.2%, i.e. the formation of propylene in high doses was observed in the presence of 5% Cr/SiO2.

Experimental and computational investigation on underlying factors promoting high coke resistance in NiCo bimetallic catalysts during dry reforming of methane

Global warming remains one of the greatest challenges. One of the most prominent solutions is to close the carbon cycle by utilizing the greenhouse gas: CO2, and CH4, as a feedstock via the dry reforming of methane (DRM). This work provided an insight into how the NiCo bimetallic catalyst can perform with high stability against coking during DRM compared to the Ni and Co monometallic catalysts, in which the experimental and computational techniques based on density functional theory were performed. It was found that the high stability against coking found on the NiCo surface can be summarized into two key factors: (1) the role of Co weakening the bond between a Ni active site and coke (2) significantly high surface coke diffusion rate on NiCo. Moreover, the calculation of the surface fraction weighted rate of coke diffusion which modeled the real NiCo particle into four regions: Ni-dominant, Co-dominant, NiCo-dominant, and the mixed region consisting a comparable amount of the former there regions, have shown that the synthesis of a NiCo particle should be dominated with NiCo region while keeping the Ni-dominant, and Co-dominant regions to be as low as possible to facilitate coke diffusion and removal. Thus, to effectively utilize the coke-resistant property of NiCo catalyst for DRM, one should together combine its high coke diffusion rate with coke removal mechanisms such as oxidation or hydrogenation, especially at the final diffusion site, to ensure that there will not be enough coke at the final site that will cause back-diffusion.

Dry Reforming of Methane on Bimetallic Pt-Ni@CeO2 Catalyst: A in situ DRIFTS-MS Mechanistic Study

Bimetallic Pt-Ni catalysts can promote catalytic dry reforming of methane (DRM) with the improved activity and deactivtaion resistance compared to the relevant monometallic catalysts. Further development of the Pt-Ni catalyst...

Recent progress in hydrogenation of esters on heterogeneous bimetallic catalysts

Monometallic catalysts based on copper phyllosilicates were actively studied in the 2000s as an alternative to the copper-chromium Adkins catalyst due to their non-toxic properties and high activity in the...

Hydrodechlorination of CHClF2 (HCFC-22) over Pd–Pt Catalysts Supported on Thermally Modified Activated Carbon

Commercial activated carbon, pretreated in helium at 1600 °C and largely free of micropores, was used as a support for two series of 2 wt.% Pd–Pt catalysts, prepared by impregnating the support with metal acetylacetonates or metal chlorides. The catalysts were characterized by temperature-programmed methods, H2 chemisorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning transmission electron microscopy (STEM) with energy dispersive spectroscopy (EDS). Overall, the results confirmed the existence of well-dispersed Pd–Pt nanoparticles in the bimetallic catalysts, ranging in size from 2 to 3 nm. The catalysts were investigated in the gas phase hydrodechlorination of chlorodifluoromethane (HCFC-22). In this environmentally relevant reaction, both the ex-chloride and ex-acetylacetonate Pd–Pt/C catalysts exhibited better hydrodechlorination activity than the monometallic catalysts, which is consistent with the previous results of hydrodechlorination for other chlorine-containing compounds. This synergistic effect can be attributed to the electron charge transfer from platinum to palladium. In general, product selectivity changes regularly with Pd–Pt alloy composition, from high in CH2F2 for Pd/C (70–80%) to the selective formation of CH4 for Pt/C (60–70%).

Glycerol Waste Valorization to Mesoxalic Acid Over a Bimetallic Pt-Pd/CNT Catalyst in Alkaline Medium

Glycerol electro-oxidation offers a green route to produce the high value added chemicals. Here in, we report the glycerol electro-oxidation over a series of multi walled carbon nano tubes supported monometallic (Pt/CNT and Pd/CNT) and bimetallic (Pt-Pd/CNT) catalysts in alkaline medium. The cyclic voltammetry, linear sweep voltammetry and chronoamperometry measurements were used to evaluate the activity and stability of the catalysts. The Pt-Pd/CNT electrocatalyst exhibited the highest activity in terms of higher current density (129.25 A/m2) and electrochemical surface area (382 m2/g). The glycerol electro-oxidation products formed at a potential of 0.013 V were analyzed systematically by high performance liquid chromatography. Overall, six compounds were found including mesoxalic acid, 1,3-dihydroxyacetone, glyceraldehyde, glyceric acid, tartronic acid and oxalic acid. A highest mesoxalic acid selectivity of 86.42% was obtained for Pt-Pd/CNT catalyst while a maximum tartronic acid selectivity of 50.17% and 46.02% was achieved for Pd/CNT and Pt/CNT respectively. It was found that the introduction of Pd into Pt/CNT lattice facilitated the formation of C3 products in terms of maximum selectivity achieved (86.42%) while the monometallic catalysts (Pd/CNT and Pt/CNT) showed a poor performance in comparison to their counterpart.