Novel heterogeneous Fe-based catalysts for carbon dioxide hydrogenation to long chain α-olefins-A review.

The thermocatalytic conversion of carbon dioxide (CO2) into high value-added chemicals provides a strategy to address the environmental problems caused by excessive carbon emissions and the sustainable production of chemicals. Significant progress has been made in the CO2 hydrogenation to long chain α-olefins, but controlling C-O activation and C-C coupling remains a great challenge. This review focuses on the recent advances in catalyst design concepts for the synthesis of long chain α-olefins from CO2 hydrogenation. We have systematically summarized and analyzed the ingenious design of catalysts, reaction mechanisms, the interaction between active sites and supports, structure-activity relationship, influence of reaction process parameters on catalyst performance, and catalyst stability, as well as the regeneration methods. Meanwhile, the challenges in the development of the long chain α-olefins synthesis from CO2 hydrogenation are proposed, and the future development opportunities are prospected. The aim of this review is to provide a comprehensive perspective on long chain α-olefins synthesis from CO2 hydrogenation to inspire the invention of novel catalysts and accelerate the development of this process.

Synthesis of Liquid Hydrocarbon via Direct Hydrogenation of CO2 over FeCu-Based Bifunctional Catalyst Derived from Layered Double Hydroxides.

Here, we report a Na-promoted FeCu-based catalyst with excellent liquid hydrocarbon selectivity and catalytic activity. The physiochemical properties of the catalysts were comprehensively characterized by various characterization techniques. The characterization results indicate that the catalytic performance of the catalysts was closely related to the nature of the metal promoters. The Na-AlFeCu possessed the highest CO2 conversion due to enhanced CO2 adsorption of the catalysts by the introduction of Al species. The introduction of excess Mg promoter led to a strong methanation activity of the catalyst. Mn and Ga promoters exhibited high selectivity for light hydrocarbons due to their inhibition of iron carbides generation, resulting in a lack of chain growth capacity. The Na-ZnFeCu catalyst exhibited the optimal C5+ yield, owing to the fact that the Zn promoter improved the catalytic activity and liquid hydrocarbon selectivity by modulating the surface CO2 adsorption and carbide content. Carbon dioxide (CO2) hydrogenation to liquid fuel is considered a method for the utilization and conversion of CO2, whereas satisfactory activity and selectivity remains a challenge. This method provides a new idea for the catalytic hydrogenation of CO2 and from there the preparation of high-value-added products.

H2O Derivatives Mediate CO Activation in Fischer-Tropsch Synthesis: A Review.

The process of Fischer-Tropsch synthesis is commonly described as a series of reactions in which CO and H2 are dissociated and adsorbed on the metals and then rearranged to produce hydrocarbons and H2O. However, CO dissociation adsorption is regarded as the initial stage of Fischer-Tropsch synthesis and an essential factor in the control of catalytic activity. Several pathways have been proposed to activate CO, namely direct CO dissociation, activation hydrogenation, and activation by insertion into growing chains. In addition, H2O is considered an important by-product of Fischer-Tropsch synthesis reactions and has been shown to play a key role in regulating the distribution of Fischer-Tropsch synthesis products. The presence of H2O may influence the reaction rate, the product distribution, and the deactivation rate. Focus on H2O molecules and H2O-derivatives (H*, OH* and O*) can assist CO activation hydrogenation on Fe- and Co-based catalysts. In this work, the intermediates (C*, O*, HCO*, COH*, COH*, CH*, etc.) and reaction pathways were analyzed, and the H2O and H2O derivatives (H*, OH* and O*) on Fe- and Co-based catalysts and their role in the Fischer-Tropsch synthesis reaction process were reviewed.

Effect of glucose pretreatment on Cu-ZnO-Al2O3 catalyzed CO2 hydrogenation to methanol.

A series of Cu-ZnO-Al2O3 catalysts (CZA) were prepared by glucose pretreatment and applied for methanol synthesis from CO2 hydrogenation. The advantages of the glucose pretreatment and the effects of glucose content were investigated by XRD, N2 physisorption, SEM, N2O chemisorption, CO2-TPD, H2-TPR, TG, and XPS characterization techniques. The influence of glucose pretreatment on the average Cu particle size and the interaction between different components, as well as the effects of the amount of glucose on the Cu specific surface area, the ratio of Cu0/Cu+ and the performance of the catalysts were discussed. The results showed that the catalysts prepared by glucose pretreatment increased the number of basic sites and had a significant advantage in methanol yield. The optimum content of glucose was beneficial to improve the catalytic performance of the CZA catalyst. The maximum space-time yield of methanol was obtained by 2 wt% glucose pretreatments at 200 °C, which was 57.0 g kg-1 h-1.

Ratiometric optical detection of pyrophosphate based on aggregation-caused dual-signal response of gold nanoclusters.

Sensing of pyrophosphate ion (PPi) has received much attention due to the strong demand for clinical diagnostics. Here, based on gold nanoclusters (Au NCs), a ratiometric optical detection method for PPi is developed by simultaneously detecting the dual signals of fluorescence (FL) and second-order scattering (SOS). The PPi is detected by inhibiting the formation of aggregates of Fe3+ with Au NCs. Binding of Fe3+ to Au NCs causes aggregation of Au NCs, which leads to fluorescence quenching and scattering increasing. The presence of PPi can competitively bind Fe3+ to re-disperse the Au NCs and finally recover the fluorescence and reduce the scattering signal. The designed PPi sensor shows a high sensitivity with a linear range 5-50 µM and a detection limit of 1.2 µM. In addition, the assay has excellent selectivity for PPi, which makes its application in real biological samples extremely valuable.

Insight into the Compositional Features of Organic Matter in Xilinguole Lignite through Two Mass Spectrometers.

Ethanolysis of lignite is an effective approach for converting organic matter of lignite to liquid coal derivatives. Xilinguole lignite (XL) was reacted with ethanol at 320 °C. Then ethanol and isometric carbon disulfide/acetone mixture were used to extract the reaction mixture in a modified Soxhlet extractor to afford extractable portion 1 (EP1) and extractable portion 2 (EP2), respectively. According to analysis of EP1 with a gas chromatography/mass spectrometer, phenolic compounds made up more than 33% of the compounds detected. This could be ascribed to the ethanolysis of XL; that is, ethanol could selectively break the Calkyl-O bonds in lignite, producing more phenolic compounds. Furthermore, a quadrupole Orbitrap mass spectrometer equipped with an atmospheric pressure chemical ionization source was used for comprehensive analysis of the compositional features of EP1. The analysis indicated that O1-3, N1O0-2, and N2S1O3-6 were predominant class species in EP1. Nitrogen atoms in NO-containing organic compounds may exist in the form of pyridine or amidogen, while oxygen atoms primarily exist in furan, alkoxy, carbonyl, and ester groups. In addition, possible chemical structures of NO-containing organic compounds were speculated.

5D-QSAR studies of 1H-pyrazole derivatives as EGFR inhibitors.

Epidermal growth factor receptor (EGFR) is highlighted as a target for anticancer treatment. Several EGFR inhibitors were approved in cancer treatment. Comparatively, 5D-QSAR is a new methodology which considers an ensemble of different induced-fit models. Based on 1H-pyrazole derivatives as EGFR inhibitors, a 5D-QSAR was studied in which the method of quasi-atomistic receptor surface modeling was used. The presented QSAR model showed contributions of the hydrogen bond acceptor, and hydrophobic and salt bridge fields to the activity. The QSAR model was statistically validated and also externally validated applying 19 compounds (test set) which were not included in the model generation process. The scramble tests were performed to further verify the robustness. Apart from exploration of the binding of 1H-pyrazole derivatives to the EGFR, the 5D-QSAR model can be helpful to design of new EGFR inhibitors. The five-dimensional quantitative structure-activity relationship (5D-QSAR) of 1H-pyrazole derivatives as EGFR inhibitors with quasi-atomistic receptor surface modeling approach is described.

Selective Conversion of Glycerol to Methanol over CaO-Modified HZSM-5 Zeolite.

Biodiesel is generally produced from vegetable oils and methanol, which also generates glycerol as byproduct. To improve the overall economic performance of the process, the selective formation of methanol from glycerol is important in biodiesel production. In the present study, a CaO modified HZSM-5 zeolite was prepared by an impregnation method and used for the conversion of glycerol to methanol. We found that the 10%CaO/HZSM-5 with Si/Al ratio of 38 exhibited highest selectivity to methanol of 70%, with a glycerol conversion of 100% under 340 ℃ and atmospheric pressure. The characterization results showed that the introduction of a small amount of CaO into the HZSM-5 did not affect the structure of zeolite. The incorporation of HZSM-5 as an acidic catalyst and CaO as a basic catalyst in a synergistic catalysis system led to higher conversion of glycerol and selectivity of methanol.

Anti-inflammatory and PTP1B inhibitory sesquiterpenoids from the twigs and leaves of Aglaia lawii.

Twelve sesquiterpenoids with seven different carbon skeletons, including four isodaucanes (1-4), an aromadendrane (5), a guaiane (6), a cadalane (7), two eudesmanes (8 and 9), two bisabolanes (10 and 11), and a megastigmane (12), were isolated from the twigs and leaves of Aglaia lawii (Wight) C. J. Saldanha et Ramamorthy. Of these compounds, amouanglienoids A (1) and B (2) are new isodaucane sesquiterpenoids. This is the first report of isodaucanes from the genus Aglaia, and amouanglienoid A (1) represents the first isodaucane containing a Δ7(8) double bond. Their structures were discerned from extensive spectroscopic analyses, single-crystal X-ray diffraction, and comparison of the experimental and calculated ECD data. In in vitro bioassays, compounds 1, 10, and 11 showed potent inhibitory effects against lipopolysaccharide (LPS)-induced inflammation in BV-2 microglial cells, while compound 11 exhibited considerable inhibition of PTP1B with an IC50 value of 16.05 ± 1.09 µM.

Cu/PCN Metal-Semiconductor Heterojunction by Thermal Reduction for Photoreaction of CO2-Aerated H2O to CH3OH and C2H5OH.

g-C3N4-based materials show potential for photoreduction of CO2 to oxygenates but are subjected to fast recombination of photogenerated charge carriers. Here, a novel Cu-dispersive protonated g-C3N4 (PCN) metal-semiconductor (m-s) heterojunction from thermal reduction of a Cu2O/PCN precursor was prepared and characterized using in situ X-ray diffraction, scanning transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet-visible (UV-vis) spectra, photoluminescence (PL) spectra, transient photocurrent response, and electrochemical impedance spectroscopy (EIS). The Cu amount in Cu/PCN and the reduction temperature affected the generation of CH3OH and C2H5OH from the photoreaction of CO2-aerated H2O. During calcination of Cu2O/PCN in N2 at 550 °C, Cu2O was completely reduced to Cu with even dispersion, and a m-s heterojunction was obtained. With thermal exfoliation, Cu/PCN showed a specific surface area and layer spacing larger than those of PCN. Cu/PCN-0.5 (12.8 wt % Cu) exhibited a total carbon yield of 25.0 µmol·g-1 under UV-vis irradiation for 4 h, higher than that of Cu2O/PCN (13.6 µmol·g-1) and PCN (6.0 µmol·g-1). The selectivity for CH3OH and C2H5OH was 51.42 and 46.14%, respectively. The PL spectra, transient photocurrent response, and EIS characterizations indicated that Cu/PCN heterojunction promotes the separation of electrons and holes and suppresses their recombination. The calculated conduction band position was more negative, which is conducive to the multielectron reactions for CH3OH and C2H5OH generation.

Cu/ZnV2O4 Heterojunction Interface Promoted Methanol and Ethanol Generation from CO2 and H2O under UV-Vis Light Irradiation.

Adopting the concurrent reduction of Cu2O during hydrothermal preparation of ZnV2O4, metal-semiconductor heterojunction Cu/ZnV2O4 nanorods were synthesized and applied to the catalytic generation of methanol and ethanol from CO2 aerated water under UV-vis light irradiation. 10Cu/ZnV2O4 obtained from 10 wt % composite amount of Cu2O exhibited a total carbon yield of 6.49 µmol·g-1·h-1. The yield of CH3OH and C2H5OH reached 3.30 and 0.86 µmol·g-1·h-1, respectively. 2.5Cu/ZnV2O4 displayed the highest ethanol yield of 1.58 µmol·g-1·h-1 due to the strong absorption in the visible light. Cu/ZnV2O4 was characterized using X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV-vis) spectra, photoluminescence (PL) spectra, transient photocurrent response, and electrochemical impedance spectroscopy (EIS). Results showed that composite Cu0-ZnV2O4 increased the surface area and tuned the energy band position, which matches the reaction potential toward methanol and ethanol. The photocatalytic activity toward CH3OH and C2H5OH on Cu/ZnV2O4 is attributed to faster transmission and a slow recombination rate of photogenerated carriers at the heterojunction interface. Multielectron reactions for the production of CH3OH and C2H5OH are promoted. Free radical capture experiments indicated that the active species boost the reaction in the order of •OH > e- > h+.

Molecular dynamics-guided receptor-dependent 4D-QSAR studies of HDACs inhibitors.

Histone deacetylases (HDACs) were highlighted as a novel category of anticancer targets. Several HDACs inhibitors were approved for therapeutic use in cancer treatment. Comparatively, receptor-dependent 4D-QSAR, LQTA-QSAR, is a new approach which generates conformational ensemble profiles of compounds by molecular dynamics simulations at binding site of enzyme. This work describes a receptor-dependent 4D-QSAR studies on hydroxamate-based HDACs inhibitors. The 4D-QSAR model was generated by multiple linear regression method of QSARINS. Leave-N-out cross-validation (LNO) and Y-randomization were performed to analysis of the independent test set and to verify the robustness of the model. Best 4D-QSAR model showed the following statistics: R2 = 0.8117, Q2LOO = 0.6881, Q2LNO = 0.6830, R2Pred = 0.884. The results may be used for further virtual screening and design for novel HDACs inhibitors. The receptor dependent 4D-QSAR model was developed for the hydroxamate derivatives as HDAC inhibitors by making use of molecular dynamics simulation to obtain conformational ensemble profile for each compound. The multiple linear regression method was used to generate 4D-QSAR model with the suitable predictive ability and the excellent statistical parameters.

Influence of Ni Precursors on the Structure, Performance, and Carbon Deposition of Ni-Al2O3 Catalysts for CO Methanation.

Three Ni-Al2O3 catalysts were prepared, in planetary ball-milling machine, by the mechanochemical method with Al(NO3)3·9H2O as the aluminum precursor, (NH4)2CO3 as the precipitant, and Ni(NO3)2·6H2O, NiCl2·6H2O, and Ni(CH3COO)2·4H2O as nickel precursors (the corresponding catalysts were labeled as Ni-NO, Ni-Cl, and Ni-Ac). The prepared catalysts were characterized by X-ray diffraction (XRD), temperature-programmed reduction (H2-TPR), and N2 adsorption-desorption technologies, and CO methanation performance evaluation was carried out for the catalysts. Results showed that the catalyst with Ni(NO3)2·6H2O as the precursor presented good Ni dispersibility and a small Ni grain size of 6.80 nm. CO conversion, CH4 selectivity, and yield of the catalyst were as high as 78.8, 87.9, and 69.8%, respectively. Carbon deposition analysis from temperature-programmed hydrogenation (TPH) characterization showed that the H2 consumption peak area of the three samples followed the order: Ni-NO (2886.66 au) < Ni-Cl (4389.97 au) < Ni-Ac (5721.65 au), indicating that the Ni-NO catalyst showed higher resistance to carbon deposition, which might be due to its small Ni grain size.

Efficient hydrogen production at a rationally designed MoSe2@Co3O4 p-n heterojunction.

During the past several years, transition metal compounds have shown high activity in the field of photocatalysis. Therefore, the MoSe2@Co3O4 with excellent photocatalytic properties through simple hydrothermal and physical mixing methods was prepared. This composite material was composed of n-type semiconductor MoSe2 and p-type semiconductor Co3O4. After optimizing the loading of Co3O4, the optimal hydrogen production can reached 7029.2 µmol g-1h-1, which was 2.34 times that of single MoSe2. In addition, some characterization methods were used to explore the hydrogen production performance of the composite catalyst under EY sensitized conditions. Among them, the UV-vis diffuse reflectance spectra suggests that MoSe2@Co3O4 exhibits stronger visible light absorption performance than the single material. Fluorescence performance and photoelectrochemical characterization experiments further prove that, the special structure formed by MoSe2 and Co3O4 and the existence of p-n heterojunction effectively accelerate the separation and transfer of carriers meanwhile inhibit the recombination probability of electron-hole pairs. Combined with other characterizations such as XRD, XPS, SEM and BET, the possible hydrogen production mechanism was proposed.

Preparation of Porous Carbon Materials Derived from Hyper-Cross-Linked Asphalt/Coal Tar and Their High Desulfurization Performance.

The development of simple and highly effective desulfurization technology is attracting more and more interest in both industrial and academic fields. Here, a new family of precursors was prepared based on hyper-cross-linked asphalt and coal tar building blocks. Thanks to the preintroduced porous structure, the precursors were converted into carbons with high surface area and large micropore volume via a uniform carbonization process. The synergistic effects of high surface area, abundant microporous structure, and the introduced polar functional groups endow the carbon materials with high desulfurization performance. The results of repeated experiments show that the adsorption capacities of five carbonized samples are higher than 40 mg S g-1, and the theoretical maximum adsorption capacity reaches 44.7 mg S g-1. Particularly, the adsorption equilibrium of all the carbonized samples can be reached in 5 min. Moreover, the recycle adsorption performance was also studied. Toluene exhibits the best elution effect among three eluents (iso-octane, para-xylene, and toluene) and the adsorption capacity remains 89% of the initial adsorption capacity after two adsorption-desorption cycles. It is believed that both innocent treatment of byproducts from petroleum industry and their high-value application for deep desulfurization in liquid hydrocarbon fuels benefit environmental protection and sustainable development.

Structurally diverse halosesquiterpenoids from the red alga Laurencia composita Yamada.

A phytochemical investigation on the MeOH extract of the red alga Laurencia composita Yamada led to the discovery of six new highly halogenated sesquiterpenoids, including two bisabolane-type sesquiterpenoids (1 and 2), one nerolidol derivative (7), and three chamigrane-type sesquiterpenoids (9, 10, and 18), together with 13 known sesquiterpenoids. Their structures, including relative configuration, were elucidated by extensive spectroscopic analysis, and by comparison with data for related known compounds. The absolute configuration at C-10 of laurecomposin A (1) was determined by the modified Mosher's method. Halonerolidol (7) is the first naturally occurring halogenated nerolidol derivative, while compositacin L (9) represents the third example of chamigranes having a C-10 carbonyl group. Antifungal, antibacterial, and receptor tyrosine kinase inhibitory activities of these isolates were evaluated. The results showed that compounds 1-3 and 5 exhibited significant antifungal activity against Microsporum gypseum (Cmccfmza) with MIC values of 4, 8, 8, and 4 µg/mL, respectively. Additionally, compounds 1-3 and 5 also displayed promising antibacterial activity against Gram-positive bacteria Staphylococcus aureus Newman strain with MIC values ranging from 10.9 to 26.8 µg/mL.

Spinel-structure catalyst catalyzing CO2 hydrogenation to full spectrum alkenes with an ultra-high yield.

Spinel-like ZnFe2O4 is tailor-made synthesized for catalyzing CO2 hydrogenation, achieving an ultra-high yield (1858.1 g kgcat-1 h-1) of full spectrum alkenes in a three-stage reactor system. This study provides rational design concepts from catalyst to equipment amelioration by combining promoter regulation and ex situ water removal, efficiently catalyzing CO2 into valuable chemical feedstocks with industrial potential.

Facile Synthesis of Proton-Type ZSM-5 by Using Quasi-Solid-Phase (QSP) Method.

Herein, a simple and green quasi-solid-phase (QSP) method for facile synthesis of proton-type ZSM-5 avoiding use of excessive water, dry gel, Na+ cation and fluoride is reported. Crystallization by using the stoichiometric amount of TPAOH (tetrapropylammonium hydroxide) at 180 °C for only 12 h gave well-structured HZSM-5 crystals with high specific surface area of 429 m2 g-1 and high thermal stability. 5MRs was observed to closely relate the formation of MFI structure and QSP method exhibits shorter induction period (t0 ), higher nucleation rate (Vn ), and faster growth rate (Vg ). Moreover, HZ-12-180 showed extremely better and rather stable catalytic activity for methanol-to-propylene reaction by comparison with commercial HZSM-5.

Insight into molecular characteristics of a Chinese coal via separation, characterization, and data processing.

Dayan lignite was subjected to thermal dissolution sequentially with cyclohexane, acetone, and methanol. Each thermal dissolution extract was subjected to further separation/enrichment using column chromatography, which was sequentially eluted with petroleum ether, a mixture of ethyl acetate and petroleum ether (vol:vol = 1:1), and ethyl acetate. The three thermal dissolution extracts and nine enrichment subfractions were characterized by an Orbitrap mass spectrometry equipped with an atmospheric pressure chemical ionization ion source. The mass spectrometry data were also statistically analyzed by principal component analysis, which can reduce the dimensionality of data and classify multiple samples according to principal components. Identified compounds in the extracts and subfractions are classified into eight classes according to the heteroatom distribution. Hydrocarbon class is mainly presented in the petroleum ether fraction, and oxygen class, nitrogen class, and oxygen-nitrogen class are distributed in both petroleum ether/ethyl acetate and ethyl acetate subfractions. The combination of different analytical methods enhances the understanding of coal at the molecular level and provides important data for downstream refining processes.

Hydroxides Ni(OH)2&Ce(OH)3 as a novel hole storage layer for enhanced photocatalytic hydrogen evolution.

In this work, a novel photocatalyst Ni(OH)2&Ce(OH)3@P-CdS was synthesized successfully by phosphorization of CdS and in situ loading of Ni(OH)2&Ce(OH)3 on the surface of P-CdS. It was found that the introduction of the element P can expand the absorption range of light, prolong the lifetime of the photoinduced carriers of CdS and enhance photocatalytic hydrogen evolution activity. Importantly, we found that Ni(OH)2&Ce(OH)3 can play the role of storing holes, which can efficiently inhibit the recombination of photoinduced electron-hole pairs, thus enhancing hydrogen evolution activity, the hydrogen evolution activity of Ni(OH)2&Ce(OH)3@P-CdS is 11.36 mmol g-1 h-1, which is 4.2 times greater than that of P-CdS. A series of characterization methods, including XRD, SEM, TEM, XPS, BET, UV-vis DRS, PL and TRPL spectroscopy and electrochemical methods (IT, LSV, EIS, MS), were performed, aimed at studying the behavior of Ni(OH)2&Ce(OH)3@P-CdS. The BET result showed that coupling Ni(OH)2&Ce(OH)3 with P-CdS can enhance the specific surface area of the compound catalyst. Also, the UV-vis DRS results showed that the introduction of Ni(OH)2&Ce(OH)3 can expand the absorption range of light. Importantly, photoluminescence spectroscopy (PL) showed that the recombination of photoinduced electron-hole pairs was hindered greatly after adding Ni(OH)2&Ce(OH)3 into the system.