Direct synthesis of H2O2 over Pd–M@HCS (M = Sn, Fe, Co, or Ni): effects of non-noble metal M on the electronic state and particle size of Pd

Direct synthesis of H2O2 in a yolk–shell structure assisted by M (M = Fe,Co,Ni,Sn) metal doping.

Fischer–Tropsch Synthesis for Light Olefins from Syngas: A Review of Catalyst Development

Light olefins as one the most important building blocks in chemical industry can be produced via Fischer–Tropsch synthesis (FTS) from syngas. FT synthesis conducted at high temperature would lead to light paraffins, carbon dioxide, methane, and C5+ longer chain hydrocarbons. The present work focuses on providing a critical review on the light olefin production using Fischer–Tropsch synthesis. The effects of metals, promoters and supports as the most influential parameters on the catalytic performance of catalysts are discussed meticulously. Fe and Co as the main active metals in FT catalysts are investigated in terms of pore size, crystal size, and crystal phase for obtaining desirable light olefin selectivity. Larger pore size of Fe-based catalysts is suggested to increase olefin selectivity via suppressing 1-olefin readsorption and secondary reactions. Iron carbide as the most probable phase of Fe-based catalysts is proposed for light olefin generation via FTS. Smaller crystal size of Co active metal leads to higher olefin selectivity. Hexagonal close-packed (HCP) structure of Co has higher FTS activity than face-centered cubic (FCC) structure. Transition from Co to Co3C is mainly proposed for formation of light olefins over Co-based catalysts. Moreover, various catalysts’ deactivation routes are reviewed. Additionally, techno-economic assessment of FTS plants in terms of different costs including capital expenditure and minimum fuel selling price are presented based on the most recent literature. Finally, the potential for global environmental impacts associated with FTS plants including atmospheric and toxicological impacts is considered via lifecycle assessment (LCA).

Mn-Decorated CeO2 nanorod supported iron-based catalyst for high-temperature Fischer–Tropsch synthesis of light olefins

The synergistic effect between Mn and Ce can improve electrons transfer from Ce to Fe and the oxygen migration. The remarkable properties promote the dissociation of CO, suppress the hydrogenation, and improve the selectivity of light olefins.

The effect of Mn on the performance of MCF-supported highly dispersed iron catalysts for Fischer–Tropsch synthesis

MCF supported iron catalysts with high loading (30%) and high dispersion were prepared. The Mn promoter influenced the reducibility and carbonization of supported iron catalysts. Higher C₅₊ selectivity was achieved by appropriate Mn promotion.

Effects of Sm on Fe-Mn catalysts for Fischer-Tropsch synthesis

Sm-promoted FeMn catalysts were prepared by the co-precipitation method and characterized by N₂ adsorption, XRD, CO-TPD, H₂-TPD, CO₂-TPD, H₂-TPR, XPS and MES. It was found that compared with the un-promoted catalyst, when Sm was added at a proper content, the catalyst showed a larger BET surface area and promoted the formation of iron particles with a smaller size. The presence of Sm could increase the surface charge density of iron, which enhanced the Fe–C bond and promoted the stability and amount of CO dissociated adsorption, as confirmed by XPS and CO-TPD. Furthermore, according to MES, Sm could promote the formation of Fe₅C₂, which was the active phase of FTS. In addition, Sm could also enhance the basicity of the catalysts and suppress the H₂ adsorption capacity, which inhibited the hydrogenation reaction and the conversion of olefins to paraffins, as verified by the results of CO₂-TPD and H₂-TPD. According to the FTS performance results, compared with the observations for the un-promoted catalysts, when the molar ratio of Sm to Fe was 1%, the CO conversion increased from 63.4% to 70.4%, the sum of light olefins in the product distribution increased from 26.6% to 32.6, and the ratio of olefins to paraffins increased to 4.18 from 4.09.

The effect of samarium on iron-based catalysts for Fischer–Tropsch synthesis was investigated.

Nanoparticles of Rh confined and tailored by LaFeO3–La2O3 on SiO2 for direct ethanol synthesis from syngas

A catalyst with a novel composition for direct ethanol synthesis from syngas was prepared and investigated in this work, which is Rh nanoparticles (NPs) highly dispersed on La₂O₃ modified LaFeO₃, and the Rh NPs/La₂O₃–LaFeO₃ was loaded on SiO₂ with high surface area.

Excellent selectivity for direct conversion of syngas to light olefins over a Mn–Ga oxide and SAPO-34 bifunctional catalyst

A selectivity for light olefins of 88.3%, the highest to date, along with 13.7% CO conversion, was achieved over a bifunctional catalyst made up of Mn–Ga oxide and SAPO-34.

Selective mild oxidation of methane to methanol or formic acid on Fe–MOR catalysts

Selective oxidation of methane to methanol or formic acid was achieved using mordenite (MOR)-supported iron catalysts with H₂O₂ as the oxidant.

Selective production of aromatics from CO2

A composite Na/Fe and SiO₂-coated HZSM-5 catalyst system has been developed for the highly selective production of aromatics (93–95%), especially para-xylene, in the liquid phase and light olefins in the gas phase from CO₂.

Low-valence or tetravalent cation doping of manganese oxide octahedral molecular sieve (K-OMS-2) materials for nitrogen oxide emission abatement

Substitutionally doped oxide catalysts with abundant oxygen vacancy defects (OVDs) can effectively improve the catalytic activity efficiency.

Hydrogenation of CO2 into hydrocarbons: enhanced catalytic activity over Fe-based Fischer–Tropsch catalysts

The conversion efficiency of CO₂ in CO₂-FTS over Fe-based catalysts is significantly enhanced by driving the conversion of the CO intermediate via the FTS reaction over a second kind of FT component, Co or Ru, without WGS activity.