Potassium promoted core–shell-structured FeK@SiO<sub>2</sub>-GC catalysts used for Fischer–Tropsch synthesis to olefins without further reduction

Ni, Zhijiang; Zhang, Xuefei; Bai, Jirong; Wang, Zhilei; Li, Xi; Zhang, Yanhu

doi:10.1039/c9nj03947c

Cited by 5 publications

(5 citation statements)

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“…Combined with our previous work [33,34], GC [35][36][37] modified mesoporous silica encapsulated metal nanoparticles can effectively improve reducibility and electron conductivity properties similar to those of expensive noble metals (Pt and Ru). In this study, FeZnNa@SiO2-C catalysts are prepared via sol-gel method with carefully controlled contents of Zn and Na.…”

Section: Introductionmentioning

confidence: 56%

Na Promoted FeZn@SiO2-C Catalysts for Sustainable Production of Low Olefins by CO2 Hydrogenation

Ni,

Cai,

Zhong

et al. 2023

Preprint

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FeZnNa@SiO2-C catalyst with graphitized carbon (GC) modified mesoporous SiO2 support metal nanoparticles was prepared by sol-gel method. The effect of adding metal Na and Zn promoters as a dispersion on the CO2 hydrogenation to low olefins was systematically studied. The results showed that Zn-Na, as a combination, promoted the absorption of CO2 and improved the conversion rate of CO2. Na as an alkaline substance can improve the absorption of more acidic CO2, improving the conversion rate of CO2 to 59.03%. Meanwhiles, addition of secondary metal Zn into Fe-based catalysts to form a surface alloy could alter the adsorption of CO2 and the activation of C-O bonds, inhibit the subsequent hydrogenation of olefins to paraffins, facilitate the reduction of Fe2O3 and the formation of active Fe5C2 species. From TEM and XRD, the formation of active Fe5C2 species was found, the selectivity of the target product was 41.07%. The deep hydrogenation of olefins is inhibited, by inhibiting their deep hydrogenations, the STY of C2=-C4= was raised again, up to 0.0436. However, the corresponding STY does not increase infinitely with the increase of Na content, and when the Na content to 6.4%, which can be shown higher CO2 hydrogenation catalytic performance. Compared with Fe@SiO2-C catalyst, Na and Zn promoted Fe-based catalysts prepared by modified sol-gel method, can be used directly for highly efficient CO2 hydrogenation to low olefins and thus will be more promising in the future.

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Section: Introductionmentioning

confidence: 56%

Na Promoted FeZn@SiO2-C Catalysts for Sustainable Production of Low Olefins by CO2 Hydrogenation

Ni,

Cai,

Zhong

et al. 2023

Preprint

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“…Combined with our previous work [29,30], GC-modified mesoporous silica-encapsulated metal nanoparticles can effectively improve reducibility and electron conductivity properties similar to those of expensive noble metals (Pt [31] and Ru [32]). In this study, FeZnNa@SiO 2 -C catalysts were prepared by the sol-gel method via regulating the amount of Na loading.…”

Section: Introductionmentioning

confidence: 64%

Sodium Promoted FeZn@SiO2-C Catalysts for Sustainable Production of Low Olefins by CO2 Hydrogenation

Ni,

Cai,

Zhong

et al. 2023

Catalysts

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A prepared FeZnNa@SiO2-C catalyst with graphitized carbon (C)-modified mesoporous SiO2 supports metal nanoparticles with the sol–gel method. The effect of adding metal Na and Zn promoters as a dispersion on the CO2 hydrogenation to low olefins was systematically studied. The results showed that Zn–Na, as a combination, could promote the absorption of CO2 and improved the conversion rate of CO2. Na as an alkaline substance can improve the absorption of more acidic CO2, which could increase the conversion rate of CO2 to 59.03%. Meanwhile, the addition of secondary metal Zn to Fe-based catalysts to form a surface alloy could alter the adsorption of CO2 and the activation of C-O bonds, inhibit the subsequent hydrogenation of olefins to paraffins, and facilitate the reduction of Fe2O3 and the formation of active Fe5C2 species. The formation of active Fe5C2 species was found in TEM and XRD, and the selectivity of the target product was 41.07%. The deep hydrogenation of olefins was inhibited, and the space–time yield (STY) of low olefins was raised again by inhibiting their deep hydrogenations, up to 0.0436. However, the corresponding STY did not increase infinitely with the increase of Na doping, and higher catalytic performance for CO2 hydrogenation could be exhibited when the Na doping reached 6.4%. Compared with Fe@SiO2-C catalyst, Na- and Zn-promoted Fe-based catalysts, prepared by the modified sol-gel method, can be used directly for highly efficient CO2 hydrogenation to low olefins and thus has a more promising application prospect in the future.

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“…Alumina, silica and titania are some of the supports that have been used with conventional iron and cobalt catalysts [19,20]. However, oxide and hydroxide supports lead to strong metal support interactions (SMSIs) [21].…”

Section: Metal Oxide Supports For Ftsmentioning

confidence: 99%

“…Auto-reduction has been successfully applied to cobaltbased catalysts, but a few studies have been done on autoreduction of iron-based catalysts to improve their performance [20,41,42]. Iron is an interesting catalyst in that it is low cost [43], there are abundant reserves, it operates over a wide temperature range and it promotes the water gas shift (WGS) reaction, which is suitable when using syngas that is highly hydrogen-deficient.…”

Section: Auto-reduction Of Iron Supported On Nanostructured Carbon Sp...mentioning

confidence: 99%

“…GC has found use as a support material for cobalt, and has also been successfully employed as a support for iron-based catalysts. Ni et al [20] prepared Fe-based FTS catalysts using a modified sol-gel method without using an additional reduction step. To ensure the success of the process, the catalyst precursor was doped with GC and potassium and exposed to argon at 700 °C for 5 h. The auto-reduced catalyst was compared to the catalyst reduced under hydrogen and higher activity was reported for the auto-reduced catalyst.…”

Section: Auto-reduction Of Iron Oxide Supported On Gcmentioning

confidence: 99%

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A Review of the Use of Carbon Nanostructures and Other Reducing Agents During Auto-reduction for Fischer–Tropsch Synthesis and Other Applications

Ncube

Moyo

2023

Catal Lett

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Fischer–Tropsch Synthesis (FTS) is an important process in the production of liquid fuels in the energy sector, due to its flexibility for use with other technologies that can produce carbon monoxide (CO) and hydrogen. Catalysts have found substantial use in FTS to improve the process efficiency. However, the use of conventional FTS catalyst reduction techniques using (hydrogen (H2), CO and syngas) to activate the metal precursor has been accompanied by strong metal-support interactions. Such limitations have driven the quest for better technologies to ensure FTS catalysis reaches its full capacity. In this article, we review the activation techniques used, with emphasis on the contemporary auto-reduction technique, which has revealed energy-saving merits. Auto-reduction has the advantage of reducing the number of steps involved in catalyst preparation prior to FTS as well as eliminating costly reducing agents such as H2, CO and syngas. Auto-reduction in this article refers to the reduction of the metal precursor using a carbon support. We firstly provide a comprehensive review of the traditional reducing agents, followed by a review of the contemporary auto-reduction technique. A comparison of the conventional FTS catalyst reduction and auto-reduction techniques is provided to allow for a fundamental understanding of the merits and demerits of both techniques. The different types of nanostructured carbon materials used in aiding auto-reduction for the FTS process are reviewed. Graphical Abstract

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Potassium promoted core–shell-structured FeK@SiO₂-GC catalysts used for Fischer–Tropsch synthesis to olefins without further reduction

Abstract: The GC and K promoted Fe-based catalysts prepared by modified sol–gel method, which omits the complex and high energy consumption reduction process, can be used directly for highly efficient FTS and thus will be more promising in the future.

Cited by 5 publications

References 44 publications

Na Promoted FeZn@SiO2-C Catalysts for Sustainable Production of Low Olefins by CO2 Hydrogenation

Na Promoted FeZn@SiO2-C Catalysts for Sustainable Production of Low Olefins by CO2 Hydrogenation

Sodium Promoted FeZn@SiO2-C Catalysts for Sustainable Production of Low Olefins by CO2 Hydrogenation

A Review of the Use of Carbon Nanostructures and Other Reducing Agents During Auto-reduction for Fischer–Tropsch Synthesis and Other Applications

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Potassium promoted core–shell-structured FeK@SiO2-GC catalysts used for Fischer–Tropsch synthesis to olefins without further reduction

Abstract: The GC and K promoted Fe-based catalysts prepared by modified sol–gel method, which omits the complex and high energy consumption reduction process, can be used directly for highly efficient FTS and thus will be more promising in the future.

Cited by 5 publications

References 44 publications

Na Promoted FeZn@SiO2-C Catalysts for Sustainable Production of Low Olefins by CO2 Hydrogenation

Na Promoted FeZn@SiO2-C Catalysts for Sustainable Production of Low Olefins by CO2 Hydrogenation

Sodium Promoted FeZn@SiO2-C Catalysts for Sustainable Production of Low Olefins by CO2 Hydrogenation

A Review of the Use of Carbon Nanostructures and Other Reducing Agents During Auto-reduction for Fischer–Tropsch Synthesis and Other Applications

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Potassium promoted core–shell-structured FeK@SiO₂-GC catalysts used for Fischer–Tropsch synthesis to olefins without further reduction