This study clarifies the ambiguous promotional mechanism of ZrO2 in conventional cobalt-based Fischer-Tropsch synthesis (FTS) catalysts by constructing inverse Co-ZrO2 model systems. Hexagonal close-packed (HCP) Co nanocrystals with well-defined exposed facets ((10-11), (0001), (11-20)) were synthesized, and ZrO2 was deposited onto their surfaces to eliminate interference from traditional supports. The optimal catalyst (NMS-Co-4Zr, 10-11) facets with 4wt% Zr) achieves exceptional performance: 93.9% C5+ selectivity with <= 1.7% CH4 formation at 170 degrees C, accompanied by robust 240 h stability. Advanced characterizations confirm the formation of Co-Zr interface, where electron transfer from ZrO2 to Co facilitates the dissociation of CO and H2. Notably, the promotional effect of the Co-Zr interface is universal across different Co facets: it lowers reaction temperatures by 30-110 degrees C and elevates C5+ selectivity to 85.5-93.9% for all modified catalysts. This work establishes the Co-Zr interface as a structure-independent activity descriptor, providing a paradigm for targeted interfacial engineering in the design of high-efficiency FTS catalysts.

The use of anatase-rutile mixed-phase TiO2 (P25) as a support improves both CO conversion and selectivity toward low-carbon alcohols (C-1-C-5 mixed alcohols) during syngas conversion over Cu-Fe bimetallic catalysts. A 61.4% selectivity to low-carbon alcohols was obtained at a CO conversion of 35.0%. The low-carbon alcohol yield (21.5%) over CuFe/P25 is 31 and 3 times higher than the yields over Cu-Fe catalysts supported on pure anatase TiO2 and pure rutile TiO2, respectively. The anatase-rutile synergy in P25 contributes to the high dispersion of Cu-Fe species and facilitates electron transfer from the P25 support to both Cu-0 and FeCx active sites via metal-support interaction. CuFe/P25 enhances both the capabilities of CO adsorption, dissociation, and non-dissociative insertion and the formation of CHx, CHO, and HCOO intermediates. These findings suggest that tuning the crystalline phase of the support constitutes a rational strategy for enhancing the catalytic activity of the metal sites.

To address the challenges of poor heat dissipation and cobalt agglomeration in Fischer-Tropsch synthesis (FTS), a ZnAl2O4-Al2O3 composite support was engineered via hydrothermal treatment and secondary calcination. The optimized CZ@A-150 catalyst achieves a synergistic balance of high thermal conductivity (1.13 W/m center dot K) and cobalt dispersion (12.1 %), leading to exceptional stability (0.21 % deactivation rate) and C5+ selectivity (90.7 %). Structural characterization reveals a composite architecture where ZnAl2O4 ensures efficient heat transfer, while the Al2O3 shell provides abundant active sites. This work establishes a quantitative relationship between composite structure parameters and catalytic performance, offering a new paradigm for designing stable FTS catalysts.

Photocatalytic CO 2 cycloaddition represents a promising route for solar‐driven synthesis of value‐added C 2+ chemicals and simultaneously mitigating anthropogenic CO 2 emissions. However, the pivotal step of direct one‐electron reduction of CO 2 to CO 2 •− requires a very high reduction potential of −1.9 V versus NHE, posing a formidable challenge. In this study, cerium‐based metal‐organic frameworks (MOFs) with linker‐induced defects, specifically Ce‐UiO‐66‐X (X = Me, H, and F), are investigated to elucidate the underlying mechanisms of photocatalytic CO 2 cycloaddition. Among them, Ce‐UiO‐66‐H, which strikes an optimal balance between light absorption and charge separation, demonstrates superior catalytic performance (yield > 90%) when coupled with tetrabutylammonium bromide (TBAB) as a co‐catalyst. In‐situ experiments and theoretical calculations reveal that TBAB stabilizes CO 2 through the formation of [Br − ···TBA + ]∼CO 2 adducts, which lowers the thermodynamic energy requirement for CO 2 •− generation from 0.66 eV (in the direct CO 2 ‐to‐CO 2 •− route) to −0.90 eV. This potential modulation promotes efficient photoelectron transfer from the MOFs to CO 2 , substantially enhancing the overall cycloaddition efficiency.

The direct conversion of syngas to higher oxygenates presents a fundamental challenge in simultaneously achieving high CO conversion, superior oxygenate selectivity, and minimal undesired C1 byproducts. Here, we develop a series of multifunctional CuxPd1/SiO2|CoMn catalysts with granule stacking architecture, which overcome the challenge by precisely controlling the spatial arrangement of active sites and the intermediate transport pathway. Systematic optimization reveals a distinct volcano-shaped relationship on Pd loadings, with the Cu28Pd1/SiO2|CoMn composite emerging as the optimal candidate. Such a catalyst achieves an exceptional oxygenates molar selectivity of 44.4% (C2+OH/ROH = 95.4%) while maintaining low C1 products (6.4% CO2 and 5.7% CH4) at considerable 27.3% CO conversion. Mechanistic studies reveal that the breakthrough stems from precise control of spatial intimacy of functional components, optimized mass balance between CHxO* and CHx*, and isolated Pd atom-mediated hydrogen spillover effects. Based on spectroscopic evidence with theoretical calculations, we propose a synergistic catalytic system wherein PdCu single-atom alloys facilitate H2 activation and CHxO* formation through hydrogen spillover, while Co0-Co2C interfaces produce abundant CHx* species. The synergistic interaction enables the migration of CHxO* intermediates from single-atom alloy sites to Co0-Co2C interfaces, where they undergo further insertion into CHx* species, ultimately leading to hydrogenation and formation of higher oxygenates.

The direct conversion of syngas to ethanol faces challenges due to catalyst inefficiencies and low ethanol yield. Bulk alloys with an appropriate atomic ratio can exhibit excellent catalytic performance. In this work, a series of RhxNiy(111) with different Rh/Ni ratios was rationally designed, and the ethanol preparation from syngas was explored based on density functional theory (DFT) calculation and microkinetic analysis. The results show that Rh1Ni1(111) was screened out to show optimum catalytic performance for ethanol production. This was attributed to a moderate quantity of charge transfer from Ni to Rh atoms, and a medium distance from the d-band center to the Fermi level. Further, to verify the catalytic performance of the catalysts at a Rh: Ni ratio of 1: 1, 1Rh1Ni/γ-Al2O3 catalyst was prepared and its catalytic performance for ethanol preparation from syngas was investigated by comparing it with that of Rh/γ-Al2O3 and Ni/γ-Al2O3. The catalytic performance of 1Rh1Ni/γ-Al2O3 has been further confirmed to be preferred over Rh/γ-Al2O3 and Ni/γ-Al2O3, achieving a 23.0 % CO conversion rate with 31.2 % ethanol selectivity.

Iron-based Fischer–Tropsch synthesis (FTS) catalyst is widely used for syngas conversion, but its iron carbide active phase is easily oxidized into Fe3O4 by the water produced during reaction, leading to the deterioration of catalytic performance. Here, we show an efficient strategy for protecting the iron carbide active phase of FTS catalyst by surface hydrophobization. The hydrophobic surface can reduce the water concentration in the core vicinity of catalyst during syngas conversion, and thus inhibit the oxidation of iron species by water, which enhances the C − C coupling ability of catalyst and promotes the formation of long-chain olefins. More significantly, it is unraveled that appropriate shell thickness plays a crucial role in stabilizing the iron carbide active phase without Fe3O4 formation and achieving good catalytic performance. The iron carbide active phase is easily oxidized by the water produced during Fischer-Tropsch synthesis, which leads to a deterioration in catalytic performance. Here, the authors present a strategy to protect iron carbide by applying surface hydrophobization.

Significant strides have been undertaken to catalyze the production of ethanol from syngas, yet the challenge remains in developing catalysts that simultaneously exhibit high activity and selectivity. In this study, we designed a high-performance Rh-Mn catalyst. The CO conversion of finally screened 1Rh1Mn/TiO2 catalyst is 51.8 %, and the total alcohol selectivity and ethanol yield are 72.1 % and 24.1 % respectively. This is the highest ethanol yield reported to date for Rh-based catalysts. Additionally, this catalyst also kept good stability. The outstanding performance is attributed to the fact that Mn facilitates the formation of Rh+ active sites, the process of CO insertion, and the generation of CH3CHO and CH3CO species—critical intermediates in ethanol production. In contrast, the unpromoted 1Rh/TiO2 catalyst showed poor ethanol selectivity and mainly produced the Rh0 species, whereas the 1Rh1Mn/TiO2 catalyst with the addition of Mn showed an increase in total alcohol and ethanol selectivity of 26.5 % and 31.3 %, respectively, as well as a reduction in CO2 of 50.4 %. In addition, we elucidated the CO2 generation and conversion pathways in the syngas to ethanol process, which is important for the effective utilization of carbon resources.

Directly converting syngas to alpha-olefins via the Fischer-Tropsch synthesis reaction serves as a competitive alternative to the traditional petroleum route, which has attracted much recent attention. However, achieving high catalytic activity over the iron-based catalyst remains a grand challenge, due to the easy oxidation of the iron carbides active phase by the water produced during reaction. Herein, we present a porous graphite-carbon encapsulated iron-based catalyst, in which the iron carbides remain stable even under harsh reaction conditions of high CO conversion or high reaction temperature. Due to the excellent anti-oxidation ability of active phase, an ultrahigh activity for producing C4+ alpha-olefins of 11.35 g center dot g(cat)(-1)center dot h(-1) can be obtained. This work provides a promising strategy to develop iron-based Fischer-Tropsch synthesis catalysts with high catalytic activity and stability by rationally stabilizing iron carbides.

Alkali earth metals are effective promoters in cobalt-based Fischer–Tropsch synthesis. To compare the similarity and difference of the effect of the same main group of alkali earth metals on Fischer–Tropsch reaction, a series of alkali earth metals-modified alumina was prepared and applied as the supports for Co catalysts. Promotion of Co/Al2O3 catalyst by alkali earth metals achieved a low CH4 selectivity,high C5+ selectivity and C3 o/p due to the lower H*/CO* ratio and enhanced CO dissociation on the surface of catalyst than the unmodified one.

Although significant efforts have been made for the direct syngas conversion to ethanol, ethanol yield remains low. Herein, we studied syngas conversion on the Rh/TiO2 catalysts with different TiO2 phase compositions. The ethanol selectivity and yield reached 34.9 and 19.4%, respectively, at a 55.7% CO conversion on the Rh/P25 catalyst. Among the supported single Rh catalysts, this is currently the highest reported ethanol yield. The catalyst also shows good stability. The mixture of anatase-rutile phases in the P25 promotes the electron transfer from P25 to Rh species because of the strong metal-support interaction. It boosts the Rh-0 active site generation, the CO dissociation, and CHx species formation, which is the significant intermediate for ethanol formation. In contrast, the Rh supported on the pure phase anatase or rutile TiO2 presents poor ethanol yield, which mainly produces the Rh+ species. This study provides an effective method to improve the ethanol yield for direct syngas conversion.

It is reported that Zirconium (Zr) is an effective promoter of cobalt-based catalysts for Fisher-Tropsch synthesis (FTS). Numerous studies have been conducted to explore the nature of the promotion. However, many of these studies focus on oxide-supported cobalt-based catalysts, in which the support effects may have partially enhanced or masked the influences of Zr. In the present work, CoZr catalysts without oxide support have been prepared across a wide range of Zr/Co molar ratio from 0.04 to 0.33 to investigate the nature of the Zr promotion. Comparing with the nano-Co3O4, the promoted catalysts exhibit excellent performance. The reaction temperature required to convert the same amount of syngas on the same amount of cobalt has decreased by about 40 degrees C. The selectivity of C-5(+) has increased from 70 similar to 81% to over 85% at the same CO conversion, and even higher than 90% on the CoZr catalysts with high Zr/Co ratio. Evidences from multiple techniques, including in situ XPS, CO-DRIFTs, CO-TPD, NH3-TPD, Py-IR, HRTEM, Raman and XRD, shows that Zr tends to occupy the coordinately unsaturated sites of nano-Co3O4. After reduction, Zr enters the lattice of Co metal, leading to the lattice expansion. Benefitting from the Zr induced structural changes of the Co metal, CO adsorption and dissociation on the CoZr catalysts have been enhanced. Besides, due to the strong interaction between Co and Zr, the growth of the Co metal crystal during H-2 reduction and O atoms adsorption on the reduced catalysts surface are inhibited significantly, which make more Co atoms available during FTS reaction. As a result, the catalytic performances are improved obviously.

A very challenging issue with Co-catalyzed FTS, surface carbon deposition and thus FTS catalyst deactivation, remains unresolved for many years. This research is designed to overcome the challenge by using theoretical calculations together with the FTS experiments. Our theoretical calculations for the first time reveal that HCP Co not only have much higher anti-carbon deposition stability but also exhibits a better anti-carbonization capability than FCC Co; the higher stability of HCP Co is attributed to its much denser active sites with the step B5-type active unit to eliminate surface carbon species. Our FTS experiments confirm the theoretical calculation results. The great dependence of anti-carbon deposition stability on the crystallographic structure and morphology of the catalysts revealed here may open a new avenue for better, stable catalysts with maximum mass-specific reactivity.

Low-cost catalysts based on Cu have emerged as promising catalysts for synthesizing ethanol from syngas, despite their limited selectivity to ethanol. This study investigates sulfur-modified Cu(100) surface for converting syngas to C2 oxygenates, and explores the intricate mechanism of C2 oxygenates formation from CO hydrogenation using density functional theory (DFT) calculations. The findings indicate that the CH2 and CH3 are the most advantageous monomers over other CHx (x = 1–3) intermediates, surpassing methanol and methane formation. This result significantly differs from observations on the Cu(100) surface. For C2 oxygenates formation, the most effective pathway involves the insertion of CHO into CH3 or CHO via C–C to generate a stable intermediate CH3CHO and OHCCHO on the S-Cu(100) surface. Additionally, the examination of electrical and structural characteristics reveals a mild charge transfer between Cu and S, which enhances the catalytic performance for syngas to C2 oxygenates. Therefore, this work provides valuable insights into the role of sulfur-modified Cu(100) surface in enhancing the selectivity to C2 oxygenates.

Carbon coated cobalt core-shell catalysts with different coating thickness were prepared by acetylene dissociation at different temperatures, the carbon coating had significant cutting effects on the Fischer-Tropsch synthesis (FTS) products. Further, different carbon species remained on the surface of carbon coated catalysts with adjusting the hydrogenolysis temperature (250, 400, 600 and 700 degrees C, respectively). Accordingly, the catalyst structure was optimized, the selectivity of C1 -C4 was reduced, while the CO conversion increased, the products in the range of C5 -C12, C13 -C20 and C5 -C20 were obtained with high selectivity. The carbon species were discerned by elemental analysis, temperature programmed hydrogenation, Raman spectra, X-ray photoelectron spectroscopy, H2 temperature programmed reduction and H2 thermogravimetry. The roles of different carbon species in FTS were elucidated, and the relationships between carbon species and FTS products selectivity were studied in detail. The deposited carbon blocks the active center, while graphitic carbon does not block the active center, nor limit the conversion rate of CO, but only limits the diffusion of long chain products.

Intrinsic kinetic experiments were performed in a wide range of process conditions over an industrial Fischer-Tropsch Synthesis (FTS) cobalt-based catalyst to obtain the kinetic models, aiming at the process/engineering design and the elucidation of the reaction mechanism. A hybrid kinetic model including the CO consumption model based on the Langmuir Hinshelwood Hougen Watson (LHHW) reaction mechanism and the lump-type product distribution model-C19+ selectivity model was developed. The obtained model, through parameters' evaluation and optimization, could provide an excellent prediction of CO conversion and C19+ selectivity in a wide process condition range. Furthermore, it was inferred that CO activation follows direct dissociation mechanism with the hydrogenation of the dissociated C* and O* to CH* and OH* respectively as the rate determining step; and the activation energy for CO consumption rate model was obtained as 80.26 kJ mol- 1.

The hcp-Co@Co2C catalysts were prepared by partial carbonization conversion of hcp-Co, which possessed rich Co-Co2C interface and strong synergy between hcp-Co and Co2C, compared with fcc-Co. The degree of carbonization conversion was easy to control, for ethyne was used as carbon source to dissociate on the surface of cobalt to form carbon species, and then carbonization conversion took place and hcp-Co@Co2C formed. The prepared hcp-Co@Co2C catalysts exhibited high selectivity of higher alcohols, compared with hcp-Co, owing to the rich interface and strong synergy between hcp-Co and Co2C.

The preparation of Fischer-Tropsch synthesis (FTS)catalyststhat exhibit excellent catalytic performance and are suitable fordirect use in a fixed-bed reactor without further reduction is crucialin industrial applications. However, only marginal progress has beenmade with respect to the preparation of cobalt-based FTS catalystsowing to tendency of metallic cobalt to oxidize easily; this tendencynecessitates the activation of these catalysts via reduction despitehaving undergone reduction treatment during their preparation. Herein,this problem has been addressed by tuning the carbon deposits (surfaceC and penetrating C) on the surface of a single-crystal cobalt catalyst.Screen-like surface C on a catalyst pretreated with 5% CO (p-Co-CO)exhibits diffusion suppression and chemical inertness to oxidizinggas, thus preventing the oxidation of metallic cobalt and resultingsimultaneously in high activity and low CH4 selectivity(7.2%) without requiring further reduction. Moreover, the exact roleof surface C and penetrating C deposited on cobalt catalysts in theFTS performance is explored. Both surface C and penetrating C enhancethe activity of the cobalt catalyst but with opposite effects on theFTS selectivity. Surface C improves the adsorption ability of bridged-typeCO and the formation of long-chain hydrocarbons, whereas penetratingC is conducive to adsorbing linear CO and increases undesired CH4 selectivity. This study clarifies the effect of depositedcarbon on the FTS reaction and provides insights into the design ofhigh-performance nonconventional FTS catalysts that do not requirefurther reduction.

There is less agreement on the role of carbon deposits during FT reaction. Identifying and characterizing carbon species of cobalt catalyst is highly challenging for the Fischer-Tropsch Synthesis (FTS). Here, a serial of pre -deposited composite carbon and single carbon are constructed, and their roles in F-T synthesis are investigated on metal cobalt catalyst excluding the texture influence of the promoter and the support. Different carbon de-posits are introduced on cobalt-based catalysts under different carbon-containing reducing atmospheres utilizing the pretreatment method. Atomic carbon, polymeric carbon, graphitic carbon, and combinations of them were distinguished by the characterization techniques of TPH, Raman and XPS. A significant difference occurred in both the catalytic activity and selectivity to methane after predeposited carbon on the Co-based catalysts. The p -Co-5 % syn-3 g-24 h-250-RO catalyst with single atomic carbon shows a remarkably low methane selectivity (4.03 %), high C5+ selectivity (76.38 %), and more importantly, excellent stability (TOS = 144 h) in FTS. Moreover, all of the Co-based catalysts containing the predeposited carbon can be directly used in the FT reaction without reduction procedure.