Dispersion Of Active Phase Research Articles

Influence of carbon template and ultrasound irradiation on combustion design of nanostructured calcium manganese oxides used in biodiesel production

Biodiesel, derived from renewable biomass, serves as a sustainable alternative to diesel produced from fossil fuels. This study explores the use of nanostructured MgO/Ca2Mn3O8 catalysts for biodiesel production through transesterification. Ca2Mn3O8 was synthesized as a support catalyst via combustion synthesis, employing carbon templates to control pore size. MgO was impregnated as the active phase using ultrasonic irradiation to enhance particle dispersion. Various characterization techniques, including XRD, FESEM, AFM, TEM, EDX, BET-BJH, and TPD-CO2, were utilized to analyse morphology, porosity, basicity, and active phase dispersion. The use of carbon templates increased pore diameters compared to catalysts without templates, while ultrasonic irradiation improved MgO dispersion. The MgO/Ca2Mn3O8 catalyst with a 10 wt% carbon template and ultrasonic irradiation achieved a maximum conversion rate of 95.5%. Its mesoporous structure, resembling a sponge, facilitated triglyceride diffusion. Stability tests indicated a 90% conversion rate after five reuses. The nanostructured MgO/Ca2Mn3O8 catalyst, with its tailored porosity and structure, demonstrated excellent performance in biodiesel production. Systematically adjusting support porosity and active site dispersion provides a viable approach for designing effective heterogeneous catalysts.

Catalytic Biomass Transformation to Hydrocarbons under Supercritical Conditions over Nickel Supported on Schungite

Liquid fuel production from biomass-derived molecules has received great attention due to the diminished fossil fuel reserves, growing energy demand, and the necessity of CO2 emission reduction. The deoxygenation of oils and fatty acids is a promising process to obtain “green” diesel. Herein, we report the results of the study of the deoxygenation of stearic acid to alkanes as a model reaction. Series of Ni-supported on schungite were obtained by precipitation in subcritical water (hydrothermal deposition) and for comparison via wetness impregnation followed, in both cases, by calcination at 500 °C and a reduction in H2 at 300 °C. The catalyst obtained via hydrothermal synthesis showed a three-fold higher specific surface area with a four-fold higher active phase dispersion compared to the catalysts synthesized via conventional impregnation. The catalysts were tested in stearic acid deoxygenation in supercritical n-hexane as the solvent. Under optimized process conditions (temperature of 280 °C, hydrogen partial pressure of 1.5 MPa, and 13.2 mol of stearic acid per mol of Ni), a close to 100% yield of C10–C18 alkanes, containing over 70 wt.% of targeted n-heptadecane, was obtained after 60 min of reaction.

High performance nickel structured catalysts prepared using EDTA for hydrogen production

Bioethanol Steam Reforming is a sustainable and environmentally friendly way to produce hydrogen. The most promising catalysts for this reaction are deactivated by carbon deposition and sintering. It is well known that the synthesis method can affect the active phase dispersion and metal‒support interactions in catalysts. In this work, structured systems based on Ni/CeO2–MgAl2O4 were prepared by using ethylenediaminetetraacetic acid, EDTA, for Ni incorporation. An EDTA‒free structured system was also prepared, for comparison. FeCrAlloy metal monoliths were used as support, as they provide efficient heat transfer due to their high thermal conductivity. The catalysts were evaluated in the ethanol steam reforming reaction at 650 °C. The Ni precursor influences the properties and catalytic performance of the systems. The systems prepared from [Ni(EDTA)]2- complex showed good reaction performance during 25 h (5.3 and 5.7 mol H2/mol C2H5OH for systems containing 1 and 5 wt% of Ni). The EDTA‒free system showed low activity. The best performing system was subjected to a regeneration process and evaluated in a second reaction cycle, showing good performance. Finally, the best structured system was compared with a powder catalyst. The results reflect that the performance of the monolithic reactor is significantly higher than the packed bed reactor.

Effects of lanthanum and ethylenediamine tetraacetic a cid

Using nickel-tungsten as active metals and TiO₂-Al₂O₃ as the support, Ni-W/TiO₂-Al₂O₃ catalysts for the hydrodesulfurization of heavy oil were prepared by wetness impregnation. The effects of the modification of lanthanum, ethylenediamine tetraacetic acid (EDTA)and La in cooperation with EDTA on the structure and hydrodesulfurization performance of the catalysts were investigated. The catalysts were characterized by XRD, BET, H₂-TPR and SEM. The results indicated that La and EDTA could weaken the interaction between support and active component, facilitate the reduction of active component, and benefit the formation of Ni-W-S phase. Addition of La or EDTA could increase the surface area and suppress the agglomeration of active metals on surface, forming smaller and highly dispersed active phase particles. The La, EDTA and combined La and EDTA modified catalysts possessed higher HDS activity than Ni-W sample, Ni-W-La-E catalyst had the highest HDS activity, and its thiophene conversion reached 99.7%.

Fibrous Material Structure Developments for Sustainable Heterogeneous Catalysis – An Overview

AbstractThe continuous development of advanced catalysts to increase process yield and selectivity is crucial. A high specific surface area and a good active phase dispersion are generally essential to create catalytic materials with a large number of active sites. Notably, materials with a fibrous morphology are appealing because of their large surface‐to‐volume ratio and flexibility. This contribution highlights the morphology of different types of fibrous structures currently under investigation, all the way from the nanoscale to the macroscale and back, where the distinction lies in the length and diameter of the fibers, as well as in the connection between the structures. Fibers with at least one submicron to nanoscale characteristic result in a higher yield, but can display practical usability issues when unbound. Therefore, fibrous structure catalysts with a balance between the small diameter and handleability are important for industrial viability. By combining different morphologies, the best of both nanomaterials and macroscopic integer materials can be combined into advanced catalytic materials. This overview showcases the large potential of these materials but makes clear that further research is needed to keep expanding the use and effectiveness of fibrous structures in catalysis.

Mesoporous Silica MCM-41 from Fly Ash as a Support of Bimetallic Cu/Mn Catalysts for Toluene Combustion.

The main outcome of this research was to demonstrate the opportunity to obtain a stable and well-ordered structure of MCM-41 synthesized from fly ash. A series of bimetallic (Cu/Mn) catalysts supported at MCM-41 were prepared via grinding method and investigated in catalytic toluene combustion reaction to show the material's potential application. It was proved, that the Cu/Mn ratio had a crucial effect on the catalytic activity of prepared materials. The best catalytic performance was achieved with sample Cu/Mn(2.5/2.5), for which the temperature of 50% toluene conversion was found to be 300 °C. This value remains in line with the literature reports, for which comparable catalytic activity was attained for 3-fold higher metal loadings. Time-on-stream experiment proved the thermal stability of the investigated catalyst Cu/Mn(2.5/2.5). The obtained results bring a valuable background in the field of fly ash utilization, where fly ash-derived MCM-41 can be considered as efficient and stable support for dispersion of active phase for catalyst preparation.

Ordered mesoporous Mg-modified silica to confine MoS2 slabs with high sulfidation and dispersion for higher alcohol synthesis via CO hydrogenation

KNiMoS as one of the most promising catalysts for the synthesis of higher alcohols (HA) from syngas but still remains challenge in the trade-off between catalytic activity and selectivity. Herein, a series of Mg-modified mesoporous silica (Mg-MS-x) with tunable morphology and pore size were synthesized by the modified-Stöber method which serve as support for KNiMoS catalysts to confine MoS2 active phases for higher alcohol synthesis (HAS) via CO hydrogenation. The ordered mesoporous Mg-modified silica enable the adjustable structure of MoS2 slabs via confinement effect, and thus enhancing the dispersion and proportion of NiMoS active phases. As a result, KNiMoS/Mg-MS-20 with dominant double-layer MoS2 stacking (∼31.2 %) and proper slab length presents the highest alcohol selectivity of 66.3 %, C2+OH selectivity of 80.5 % in the alcohol and space–time yield (STY) of 91.6 mg g-1h−1 for C2+OH. The connections between HAS performance and the structural property of ordered mesopore confined MoS2 catalysts were also discussed to get insight into the structure-performance relationship. This work proposed a promising route to fabricate ordered mesoporous silica confined KNiMoS with different morphology and pore size, which significantly enhance the selectivity of HA and the ratio of C2+OH/ROH in selective CO hydrogenation.

Nickel catalyst supported on SiC incorporated SiO2 for CO2 methanation: Positive effects of dysprosium promoter and microwaves heating method

In this work, Dy-promoted Ni/SiC-SiO2 catalysts with varied Dy loadings (0–1 %) were developed using the wet impregnation method and evaluated for their effectiveness in CO2 methanation. The characterization results reveal that Dy addition can reduce the Ni crystallite size, enhance the dispersion of active phase and increase the catalyst’s reducibility. Among the prepared catalysts, the 0.5 %Dy-10 %Ni/SiC-SiO2 demonstrated the highest CH4 selectivity (100 %) and CO2 conversion (73.9 %) at 350 °C owing to its highest basic sites and H2 chemisorption capacity. The performance of this Dy-promoted catalyst diluted with different amounts of SiC, which was employed as a microwave susceptor and high thermal conductive dilution material, was also investigated in both microwave and electric reactor. Microwave heating leads to higher CO2 conversion compared to electric heating, regardless of reaction temperature and dilution factor due to selective heating and the random occurrence of hot spots, which are usually considered as micro-plasmas in the catalyst bed. However, further increase quantity of SiC decreased both CO2 conversion and CH4 selectivity regardless of heating method. This may be attributed to the appearance of extreme overheating and the absence of gentle overheating with increased amount of SiC in the microwave and electric reactors, respectively. The temperature-programmed oxidation results demonstrated that carbon deposition on the 0.5 %Dy-10 %Ni/SiC-SiO2 catalyst during 30 h of reaction can be significantly suppressed by microwave.

Performance Study of Ni/Si-MCM-41 Catalysts, Synthesized with Different Silica Sources, and their Application on Methane Dry Reform to Produce Green Hydrogen

The present work carried out an extensive and deepened study regarding the physicochemical characteristics of two Si-MCM-41-type supports, synthesized employing two distinct silica precursors, tetraethyl orthosilicate (TEOS) and rice husk ash (RHS), with the dispersion of nickel on the surface of the catalytic support. The direct influence of the active phase dispersion was analyzed, making a relationship with the formation of coke and with its performance on methane dry reform (DRM). The catalysts were prepared with 5, 10, and 20% (m/m) of Ni by wet impregnation method (with excess solvent), calcined at 800 ºC for 6 h, and characterized by the techniques of scanning electron microscopy and energy dispersive spectroscopy (SEM/ EDS), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET)/Barret-JoyerHalenda (BJH), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), temperature-programmed ammonia desorption (TPD-NH3), and H2-temperature-programmed reduction (TPR). The DRM experiments were carried out at 800 °C for 24 h with a 1:1 CH4:CO2 molar ratio. Analyzes of gaseous products were performed in gas chromatography (GC) and the coke produced was estimated by temperature-programmed oxidation (TPO). The best reaction results were obtained for catalysts with 20% nickel, which were selective and stable within 24 h of reaction. Comparing the TEOS and RHS catalysts for 20% Ni, the DRM results were very similar. The catalysts on RHS support demonstrated a significant low formation of coke, which can be considered negligible in a 24 h reaction.

Hindering nanoparticle growth in reverse microemulsion synthesized CeO2/γ-Al2O3 reverse water gas shift catalyst

Efficient CO2 conversion to fuels and chemicals is of paramount importance for mitigating greenhouse gas emissions that accelerate climate change. In CO2 conversion reactions, catalyst nanoparticle growth and sintering under reaction conditions pose significant challenges, limiting the catalytic performance and catalyst stability. In this study, high surface area CeO2/γ-Al2O3 nano-catalysts were synthesized via the reverse microemulsion method and evaluated for reverse water gas shift. The effect of the active phase dispersion on the CeO2 nanoparticle growth was investigated via X-ray diffraction and gas adsorption. The 47.9 wt% CeO2/Al2O3 catalyst showed complete selectivity to CO generation, while attaining nearly equilibrium values for CO2 conversion at 600 °C and 8000 mL/(g h). As compared to bulk CeO2, nanoparticle growth in the CeO2/Al2O3 catalyst was hindered significantly, resulting in a relatively stable catalytic performance, similar to that of the bulk CeO2. Our findings reveal that the reverse microemulsion synthesized γ-Al2O3 support significantly decreases CeO2 nanoparticle growth and agglomeration. This reduction in nanoparticle sintering contributes to the enhanced catalytic performance and stability, facilitating efficient CO2 reduction.

Modifying the active phase structure of Ni2P/Al2O3 by Ga introduction for improved hydrodesulfurization of diesel

Modifying the structure of active phase is an effective protocol to improve the catalytic activity of hydrodesulfurization (HDS) catalyst. Here, a variety of mesoporous GaAlOx supports with various Ga doping amount were synthesized by a facile hydrothermal strategy. The corresponding Ni2P supported catalysts were fabricated via a conventional impregnation and temperature-programmed reduction method, and their catalytic performances for 4,6-DMDBT HDS were examined. The experimental analyses show that the introduction of Ga substantially influences the geometric and electrical structure of Ni2P active phase on Ni2P/GaAlOx catalysts. The metal-support interaction is effectively abated with the elevation of Ga doping amount, thereby increasing the d-electron density of Ni species and boosting the pre-hydrogenation (HYD) route, thereupon enhancing the HDS performances of corresponding Ni2P/GaAlOx catalysts. Therein, Ni2P/GaAlOx-0.50 exhibits the highest activity with 70.1% 4,6-DMDBT conversion because of the optimal morphology and percentage of active phase, as well as distinguished redox and acid property. Further increasing the Ga loading, however, inhibits the HDS activity of Ni2P/GaAlOx-1.0 catalyst due to the decrease in the fraction and dispersion of active phases. Therefore, this work may shine light on the understanding of structure–activity of HDS catalyst and thereafter the preparation of HDS catalysts with high efficiency in future.

Activated biochars as sustainable and effective supports for hydrogenations

Activated biochars were obtained from pyrolysis and CO2-physical activation of four different biomasses including tannery shaving waste (T), vine wood waste (W), barley waste (B) and Sargassum, brown macroalgae of Venice lagoon (A). The potential of obtained carbonaceous materials as the supports of Ni,Al catalysts was investigated in levulinic acid (LA) conversion to γ-valerolactone (GVL) as a model hydrogenation reaction. Al-containing species as the Lewis acid sites for the dehydration step were incorporated to the supports using wet impregnation or precipitation. Ni as a hydrogenation active phase was added to the supports via wet impregnation. Biochar-based supports and catalysts were characterized by AAS, elemental analysis, FTIR, N2 physisorption, XRD, SEM, EDS, TEM, He-TPD, NH3-TPD and TPR techniques. The catalysts were tested for LA hydrogenation to GVL in a batch system and aqueous medium. The results showed that Ni supported on activated biochar was not active due to a lack of Lewis acid sites for dehydration. Precipitated Al-containing species on the biochar-based supports demonstrated a better catalytic performance in the reaction compared to impregnated one because of different interactions with the support and Ni species. Among different supports, the activated biochars obtained from T and W acted as the best ones. A higher catalytic efficiency was strongly influenced by the chemical (aromaticity and stability, presence of N,O-doped and functional groups), textural (the porous texture and surface area), and morphological (higher dispersion of active phases) properties of activated biochars obtained from different biomasses with different natures.

Novel approach for synthesis of highly active nanostructured MgO/ZnAl2O4 catalyst via gel-combustion method used in biofuel production from sunflower oil: Effect of mixed fuel

A series of MgO/ZnAl2O4 nanocatalysts was prepared in order to conversion of sunflower oil to green fuel through transesterification reaction. The ZnAl2O4 spinel was synthesized using combustion method with different mixtures of urea and citric acid as fuel. MgO was also loaded on the catalysts as the active phase by impregnation method. the physicochemical properties of synthesized MgO/ZnAl2O4 nanocatalysts was evaluated with TGA/DTG, XRD, FESEM, EDX-dot mapping and nitrogen adsorption–desorption technique. XRD patterns of all samples showed crystalline phase of zinc aluminate without any impurities. The porous morphology as well as high degree of active phase dispersion was observed in samples prepared with mixed fuel. Using mixed fuel with urea to citric acid ratio of 0.5 led to create more pores in range of 10–20 nm. It is worth mentioning that the results of the catalytic performance test of the synthesized catalysts revealed that the highest conversion rate of 98.45 % was obtained in the synthesized sample with a ratio of urea to citric acid of 1:2. Furthermore, this sample illustrated superb stability in the reusability examination so that even over after five recovery cycles, the conversion triglyceride just decreased to 91.1 %.

In-situ polymerization intercalation of montmorillonite to achieve Co3O4 barrier dispersion for direct catalytic decomposition of N2O

Herein, the Co-MMT (Co3O4-montmorillonite) catalysts were prepared by coordination-deposition (Co(0.015)-MMT-2(CD)) and deposition-precipitation method (Co(0.015)-MMT-2 (DP)) for the N2O direct decomposition, respectively. The structure, texture, and surface properties of the catalysts are characterized by XRD, TEM, FT-IR, Raman, XPS, and so on. The results show that compared with Co(0.015)-MMT-2(DP), Co(0.015)-MMT-2(CD) achieves barrier dispersion of active phase (Co3O4) by using the layer structure of montmorillonite and has a smaller Co3O4 crystal size, richer oxygen vacancy and higher content of Co2+Oh. In addition, the results of DFT calculation and kinetic calculation indicate that Co2+Oh possesses higher reaction activity than Co2+Td and Co3+Oh, and the TOF value of Co(0.015)-MMT-2(CD) at 400 ℃ is 3 times higher than that of Co(0.015)-MMT-2(DP). Therefore, the Co(0.015)-MMT-2(CD) catalyst shows excellent catalytic activity and tolerance to impurity gases (H2O, NO, and O2), and it can maintain 100% conversion at least 50 h for the direct catalytic decomposition of N2O.

An Efficient Investigation and Machine Learning-Based Prediction of Decolorization of Wastewater by Using Zeolite Catalyst in Electro-Fenton Reaction

The shortage of water resources has caused extensive research to be conducted in this field to develop effective, rapid, and affordable wastewater treatment methods. For the treatment of wastewater, modern oxidation techniques are desirable due to their excellent performance and simplicity of implementation. In this project, wet impregnation and the hydrothermal technique were applied to synthesize a modified catalyst. Different analysis methods were used to determine its characteristics, including XRD, BET, FT-IR, NH3−TPD, and FE-SEM. The catalyst features a spherical shape, large surface area, high crystallinity, and uniform active phase dispersion. In order to eliminate the methylene blue dye as a modeling effluent, the catalyst’s performance was examined in a heterogeneous quasi-electro-Fenton (EF) reaction. The impact of various performance characteristics, such as catalyst concentration in the reaction medium, solution pH, and current intensity between the two electrodes, was elucidated. According to the results, the best operational circumstances included a pH level of 2, a catalyst concentration of 0.15 g/L, and a current of 150 mA, resulting in the greatest elimination efficiency of 101%. The catalyst’s performance was stable during three consecutive tests. A pseudo-first-order model for the elimination reaction’s kinetics was developed, which showed acceptable agreement with the experimental results. This study’s findings help clarify how well the heterogeneous zeolite catalyst functions in the pseudo-EF reaction. The results revealed the method’s potential to be implemented in wastewater treatment. An artificial neural network model is utilized to predict the removal percentage. The hyperparameter tuning is used to find the best model, and the model achieved an MAE of 1.26% and the R2 was 0.99.

Reactive adsorption desulfurization of model FCC gasoline on Ni-based adsorbents: Effect of active phase dispersion on activity and HDS/HYD selectivity

A series of Ni/ZnO-Al2O3 and Ni/ZnO-SiO2 adsorptive-catalytic adsorbents differing in the support composition (the Al2O3, SiO2 and ZnO covered) and nickel surface content have been synthesized. Zinc oxide-based supports and Ni supported adsorbents were characterized using X-ray diffraction (XRD), temperature-programmed reduction (TPR), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and N2 physisorption to study their structural properties and morphology. Desulfurization (HDS) and hydrogenation (HYD) activity of the synthesized systems, as well as the HDS/HYD selectivity factor (SF) were determined in the process of reactive adsorption of model FCC gasoline containing thiophene (1000 ppm of sulfur) and 1-hexene (20 wt%) on a fixed-bed flow-type laboratory unit. It has been established that an increase in the nickel surface content and average particle size of the active phase leads to an enhancement of the HDS/HYD selectivity factor regardless of the support used. The Ni/ZnO-SiO2 sample with 8 at Ni/nm2 exhibited the highest HDS/HYD selectivity at a high level of thiophene conversion (> 96%) in the chemisorption mode. The evolution of catalytic properties of Ni-Zn sorbents during FCC gasoline desulfurization process was estimated as well as characteristics of sulfurized samples. Relationships between the turnover frequency number in HDS and HYD reactions, HDS/HYD selectivity factor and size of Ni particles are discussed. DFT calculations of the adsorption thermodynamics were carried out for three model components and adsorption in the diffusion-controlled mode of the feedstock was studied for a series of nickel clusters. The results helped to explain the catalytic behavior of Ni-based sorbents in chemisorption and catalytic (after sulfur saturation) conditions.

Adjustment of the ZSM-5 zeolite support towards the efficient hydrogen production by ethanol steam reforming on cobalt catalysts

The world is on track for replacing fossil fuels with alternative energy carriers. In the face of the ongoing global energy transformation, the focus is on hydrogen. Its production in the ethanol steam reforming (ESR) process with the use of a substrate from bio-sources deserves special attention. The ESR process requires a catalyst, which should be selective and resistant to the deactivation processes. We have taken a challenge to develop the cobalt catalyst based on the ZSM-5 zeolite support. We synthesized a series of catalysts based on zeolite with increasing Si/Al ratios (32, 750, ∞ that is Al-free zeolite) and different zeolite morphology. The substantial difference in their performance we discussed based on the multifaceted physicochemical characterization and unique operando UV–Vis and FT-IR spectroscopy studies in the ESR conditions. We have checked the effect of potassium introduction to the Co|ZSM-5 catalyst. The increase in ethanol conversion and decrease in selectivity to undesired C2H4 product with the decrease of the Al content, and further competitive activity and stability of the Al-free catalyst we discussed in terms of the zeolite acidity and its impact on the cobalt phase oxidation state. The advantage of nanometric zeolite over the micrometric one, we attributed to much better dispersion of cobalt active phase over its surface. Thus, the adjustment of zeolite support properties allows us to get the extraordinary ESR catalyst. Our results overthrow the existing paradigm of low activity and stability of zeolite-based ESR catalysts, opening the way to the development of competitive catalysts that give real hope for implementation.

Facile hydrothermal synthesis of ZnO nanoparticles on silicalite-1: Effect of ultra ZnO Nano size on desulfurization activities

Reactive adsorption desulphurization (RADS) is an excellent technique for producing ultra-clean sulphur-free fuel in mild operating conditions. The sulphur adsorption capacities of the catalysts strongly relate to the stable nano size of ZnO nanoparticles, dispersion of active phases, and the acidity of the catalysts. In this work, a series of ultra nano-sized ZnO nanoparticles with a nano-size of 2–8 nm supported on silicalite-1 were synthesized via a homogeneous hydrothermal technique and utilized as a support for the dispersion of Ni nanoparticles. The RADS activity of the NiZnS-1 catalyst for thiophenic compound substantially increased from 163 mg S/g to 205 mg S/g with the decrease of the ZnO particle size from 8 nm to 2 nm. The NiZnS-1 adsorbents were characterized through N2 adsorption-desorption, Raman spectroscopy, X-ray diffraction, High-resolution transmission electron microscopy, and Temperature-programmed desorption of ammonia. Catalytic activity tests show that NiZnS-1(6) adsorbent with ZnO particle size of 2–3 nm achieved an excellent breakthrough sulphur adsorption capacity of 57.5mgS/g and accumulative sulphur adsorption capacities of 205 mg S/g while dealing with model gasoline (1500 mg/L). Which is four folds higher than NiZnS-1(20) adsorbent with a compromised RADS capacity of 163 mg S/g. This superior desulphurization activity and sulphur adsorption capacity for NiZnS-1 adsorbent strongly depend on to the size of ZnO nanoparticles, the diffusion rate of the reactant’ and product molecules, the adsorbent total acidity and ZnO/Ni nanoparticles dispersion on the support. Upon five desulfurization regeneration cycles, NiZnS-1 showed high stability without apparent activity loss, revealing that the ZnO particle size is intact after multiple cycles. A mechanism is proposed based on the desulphurization results.

Hybrid alumina-1D titania nanotube materials as supports for NiMo catalysts with improved activity in hydrodesulfurization

γ-Alumina materials modified with different amounts of 1D titania nanotubes were synthesized, characterized and used as supports for NiMo catalysts evaluated in the hydrodesulfurization of dibenzothiophene and 4,6-dimethyldibenzothiophene. Alumina and titania components in hybrid supports exist as separate domains maintaining their characteristic mesopore structure. After thermal treatment of supports, 1D titania was partially transformed to anatase nanocrystals of <15 nm in size. The presence of 20–40 wt% of 1D titania in alumina increased the activity of the catalysts due to lower metal-support interaction, larger proportion of octahedral Mo oxide species and increased dispersion of MoS2 active phase.

Functional porous poly(ionic liquid)s catalyst for highly integrated capture and conversion of flue gas CO2

Most of the strategies developed to convert CO2 to high value-added chemicals require high purity of CO2. To reduce the energy consumption of CO2 purification, this work reports the preparation of a poly(ionic liquid)s catalyst Ag@Co-PIN-NH2 with dual functions of adsorption and activation. The –NH2 functional group was introduced into the organic polymer framework and the Ag(I) active phase was deposited on the framework carrier through anionic exchange reaction. The highly polar surface and highly dispersed active phase of Ag@Co-PIN-NH2 facilitated the carboxylative cyclization and hydration of propargylic alcohols with exclusive chemo-selectivity under low pressure and concentration of CO2 (1 bar, 15 % CO2 in 85 % N2, v/v simulated flue gas). Furthermore, Ag@Co-PIN-NH2 exhibited broad substrate scope, excellent catalytic diversity and reusability. This work provides momentous reference information for conversion of carbon resources in industrial flue gas into valuable chemicals.