From hydrophilic to hydrophobic: A promising approach to tackle high CO2 selectivity of Fe-based Fischer-Tropsch microcapsule catalysts

Sun

et al. 2023

Cryst. Res. Technol.

Capsule catalysts offer a unique spatial confinement effect, which effectively minimizes byproduct formation, enhances catalyst life, and promotes tandem reactions, thus reducing energy, time, and raw material consumption. This review presents an overview of recent advances and research progress in capsule catalysts, highlighting major breakthroughs in preparation strategies over the past decade. Innovative synthesis methods are discussed based on synthesis principles, difficulty, and effectiveness, along with an analysis of growth mechanisms and the advantages and disadvantages of zeolite shells. Application status of capsule catalysts in high‐value hydrocarbon synthesis from syngas, low‐carbon alkane dehydroaromatization, and CO2 hydrogenation reactions is explored. Finally, challenges and future prospects for scientific research and industrial applications of capsule catalysts are addressed.

Section: Syngas To Olefinmentioning

confidence: 99%

Synthesis, Types, and Applications of Zeolite Capsule Catalysts

Sun

et al. 2023

Cryst. Res. Technol.

“…Similarly, the CO 2 selectivity was reduced by encapsulating a Fe‐zeolite catalyst with hydrophobic silicalite‐1 shells during syngas conversion. [ 39 ]…”

Section: Syngas Conversion Over Zeolite‐based Catalystsmentioning

confidence: 99%

Applications of Zeolites to C1 Chemistry: Recent Advances, Challenges, and Opportunities

2020

However, due to growing concerns regarding crude oil depletion and increasing environmental requirements, finding abundant fossil hydrocarbons with high H 2 /C ratios as well as alternative carbon resources has become crucial to maintaining sustainable, environmentally benign systems that can aid human development. [2] Thus, one-carbon (C1) chemistry, which is the chemistry of C1 molecules that can be derived from sources other than fossil hydrocarbons, including carbon monoxide (CO), carbon dioxide (CO 2), methane (CH 4), methanol (CH 3 OH), and formic acid (HCOOH), has emerged and plays important roles in the energy supply and high-value chemical preparation. [1,3] These C1 resources can be obtained from natural gas, shale gas, coal, biomass, solid wastes, and CO 2 emissions. [3a,4] Extensive studies have been dedicated to the catalytic conversion of C1 molecules, including production of dimethyl ether (DME) and liquid fuels from syngas (a mixture of CO and H 2); production of methanol, light olefins, and even aromatics from CH 4 ; and production of hydrogen from HCOOH. [5] All of these transformations require metallic catalytic species such as single atoms; clusters; or oxides, carbides, or alloy particles (e.g., Rh-, AuPd-, Fe 3 O 4-, and Fe 5 C 2-based catalysts). However, these isolated metallic species suffer from severe sintering due to a lack of confinement effects from supports, which leads to poor catalytic stability and decreased selectivities toward their target products. The efficient production of a specific range of hydrocarbons or oxygenates remains a difficult scientific and technical challenge. Overcoming product selectivity limitations and improving catalyst stabilities via catalyst designs are important areas of research. Zeolites are an important class of shape-selective catalysts with uniform micropores, tunable acidities, and high thermal and hydrothermal stabilities. Over the past decade, they have gained broad popularity and been applied to various industrially important catalytic processes. [6] In particular, the design and development of zeolite-based mono-, bi-, and multifunctional catalysts that combine the advantages of zeolites with those of metallic catalytic species have boosted the application of zeolites to C1 chemistry. As shown in Figure 1, value-added hydrocarbons and oxygenates can be produced from C1 molecules via various catalytic routes over zeolite-based catalysts. By May of 2020, the Structure Commission of the International C1 chemistry, which is the catalytic transformation of C1 molecules including CO, CO 2 , CH 4 , CH 3 OH, and HCOOH, plays an important role in providing energy and chemical supplies while meeting environmental requirements. Zeolites are highly efficient solid catalysts used in the chemical industry. The design and development of zeolite-based mono-, bi-, and multifunctional catalysts has led to a booming application of zeolite-based catalysts to C1 chemistry. Combining the advantages of zeolites and metallic catalytic species has promoted the catal...

“…However, Fe‐based catalysts have high WGS activity and are prone to generate more CO 2 , thereby reducing carbon utilization. Studies have shown that hydrophobic modification of Fe‐based catalysts can reduce WGS activity and thus reduce the formation of CO 2 and prolong the catalyst life [10,18–21] . Yan et al [22] .…”

Section: Introductionmentioning

confidence: 99%

“…Studies have shown that hydrophobic modification of Fe-based catalysts can reduce WGS activity and thus reduce the formation of CO 2 and prolong the catalyst life. [10,[18][19][20][21] Yan et al [22] prepared Fe 3 O 4 @SiO 2 -PFTS catalysts with hydrophobic and oleophobic properties by hydrothermal process, stober method, and silylation reaction using perfluorodecyltrlethoxysilane (PFTS) as silylation agent. The evaluation results showed that the hydrophobic modification significantly reduced the WGS reactivity, and the CO 2 selectivity decreased from 44 % to 12 %.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Hydrophobically Modified Iron Catalysts with Hexadecyltrimethoxysilane on Fischer‐Tropsch Synthesis

Chen

Meng

et al. 2023

ChemistrySelect

Hydrophobic modification of Fischer-Tropsch synthesis catalyst can inhibits water gas shift(WGS) reaction and regulates product distribution. Herein, a series of hydrophobic Fe 2 O 3 @SiO 2 -xHDTMS (Hexadecyltrimethoxysilane, HDTMS. x represents the amount of HDTMS.) catalysts with various HDTMS content were synthesized for Fischer-Tropsch synthesis to light hydrocarbons. The Fe 2 O 3 @SiO 2 -xHDTMS catalysts were characterized by X-ray diffractometer(XRD), scanning electron microscope(SEM), transmission electron microscope(TEM), fourier transform infrared spectrometer(FT-IR) and contact angle measuring instrument(CAMI). After HDTMS modification, the hydrophobicity of the catalyst is significantly improved, the selectivity of the catalyst to CO 2 is significantly reduced due to the inhibition of WGS reaction, and the selectivity of hydrocarbon products is significantly improved. This indicates that HDTMS is very suitable as a silanizer for hydrophobic modification of Fischer-Tropsch synthesis catalysts. With the increase of HDTMS content, the hydrophobicity of the catalyst always increased, but the selectivity of CO 2 in Fischer-Tropsch synthesis products decreased first and then increased, and the selectivity of hydrocarbons increased first and then decreased, indicating that the content of HDTMS has a significant impact on the hydrophobicity and catalytic performance of the catalyst.