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Reversing the thermal induced sintering phenomenon and forming high temperature stable fine dispersed metallic centers with unique structural and electronic properties is one of the ever-lasting targets of heterogeneous catalysis. Here we report that the dispersion of metallic Ni particles into under-coordinated two-dimensional Ni clusters over γ-Mo 2 N is a thermodynamically favorable process based on the AIMD simulation. A Ni-4nm/γ-Mo 2 N model catalyst is synthesized and used to further study the reverse sintering effect by the combination of multiple in-situ characterization methods, including in-situ quick XANES and EXAFS, ambient pressure XPS and environmental SE/STEM etc. The under-coordinated two-dimensional layered Ni clusters on molybdenum nitride support generated from the Ni-4nm/γ-Mo 2 N has been demonstrated to be a thermally stable catalyst in 50 h stability test in CO 2 hydrogenation, and exhibits a remarkable catalytic selectivity reverse compared with traditional Ni particles-based catalyst, leading to a chemo-specific CO 2 hydrogenation to CO. Reversing the thermal induced sintering phenomenon and forming high temperature stable fine dispersed metallic centers is one of the ever-lasting targets in heterogeneous catalysis. Here the authors report the dispersion of metallic Ni particles into under-coordinated two-dimensional Ni clusters over γ-Mo 2 N.

Enhancing the intrinsic activity and space time yield of Cu based heterogeneous methanol synthesis catalysts through CO 2 hydrogenation is one of the major topics in CO 2 conversion into value-added liquid fuels and chemicals. Here we report inverse ZrO 2 /Cu catalysts with a tunable Zr/Cu ratio have been prepared via an oxalate co-precipitation method, showing excellent performance for CO 2 hydrogenation to methanol. Under optimal condition, the catalyst composed by 10% of ZrO 2 supported over 90% of Cu exhibits the highest mass-specific methanol formation rate of 524 g MeOH kg cat −1 h −1 at 220 °C, 3.3 times higher than the activity of traditional Cu/ZrO 2 catalysts (159 g MeOH kg cat −1 h −1 ). In situ XRD-PDF, XAFS and AP-XPS structural studies reveal that the inverse ZrO 2 /Cu catalysts are composed of islands of partially reduced 1–2 nm amorphous ZrO 2 supported over metallic Cu particles. The ZrO 2 islands are highly active for the CO 2 activation. Meanwhile, an intermediate of formate adsorbed on the Cu at 1350 cm −1 is discovered by the in situ DRIFTS. This formate intermediate exhibits fast hydrogenation conversion to methoxy. The activation of CO 2 and hydrogenation of all the surface oxygenate intermediates are significantly accelerated over the inverse ZrO 2 /Cu configuration, accounting for the excellent methanol formation activity observed. Enhancing the intrinsic activity and space time yield of Cu based heterogeneous methanol synthesis catalysts is one of the major topics in CO 2 hydrogenation. Here the authors develop a highly active inverse catalyst composed of fine ZrO 2 islands dispersed on metallic Cu nanoparticles.

Nickel is the most widely used inexpensive active metal center of the heterogeneous catalysts for CO 2 hydrogenation to methane. However, Ni-based catalysts suffer from severe deactivation in CO 2 methanation reaction due to the irreversible sintering and coke deposition caused by the inevitable localized hotspots generated during the vigorously exothermic reaction. Herein, we demonstrate the inverse CeAlO x /Ni composite constructed on the Ni-foam structure support realizes remarkable CO 2 methanation catalytic activity and stability in a wide operation temperature range from 240 to 600 °C. Significantly, CeAlO x /Ni/Ni-foam catalyst maintains its initial activity after seven drastic heating-cooling cycles from RT to 240 to 600 °C. Meanwhile, the structure catalyst also shows water resistance and long-term stability under reaction condition. The promising thermal stability and water-resistance of CeAlO x /Ni/Ni-foam originate from the excellent heat and mass transport efficiency which eliminates local hotspots and the formation of Ni-foam stabilized CeAlO x /Ni inverse composites which effectively anchored the active species and prevents carbon deposition from CH 4 decomposition. An inverse CeAlO x /Ni/Ni-foam structured catalyst with high thermal stability and water resistance is shown to be effective at CO 2 methanation across a wide temperature range because of efficient heat/mass transport.

The hydrogenation activity of noble metal, especially platinum (Pt), catalysts can be easily inhibited by the presence of a trace amount of carbon monoxide (CO) in the reaction feeds. Developing CO-resistant hydrogenation catalysts with both high activity and selectivity is of great economic interest for industry as it allows the use of cheap crude hydrogen and avoids costly product separation. Here we show that atomically dispersed Pt over α-molybdenum carbide (α-MoC) constitutes a highly CO-resistant catalyst for the chemoselective hydrogenation of nitrobenzene derivatives. The Pt1/α-MoC catalyst shows promising activity in the presence of 5,000 ppm CO, and has a strong chemospecificity towards the hydrogenation of nitro groups. With the assistance of water, high hydrogenation activity can also be achieved using CO and water as a hydrogen source, without sacrificing selectivity and stability. The weakened CO binding over the electron-deficient Pt single atom and a new reaction pathway for nitro group hydrogenation confer high CO resistivity and chemoselectivity on the catalyst.Atomically dispersed Pt on an α-MoC support exhibits high CO tolerance during selective hydrogenation of nitrobenzene and its derivatives.

Although great success has been achieved in asymmetric Claisen rearrangement for the synthesis of chiral γ,δ-unsaturated carbonyl compounds bearing vicinal tertiary-quaternary stereocenters, the development of asymmetric versions for stereodivergent construction of adjacent quaternary-quaternary stereocenters remains a formidable challenge because of the high steric hindrance. Here we report a catalytic enantioselective dearomatization Claisen rearrangement of allyl furyl ethers catalyzed by chiral N,N ′-dioxide-Ni II complex catalysts. A variety of chiral γ,δ-unsaturated carbonyl compounds bearing vicinal quaternary-quaternary stereocenters were obtained with excellent outcomes under mild conditions. Furthermore, we disclosed that by matching the configuration of the catalysts and the alkene unit of the substrates, four stereoisomers of the products could be prepared in excellent yields and stereoselectivities. Finally, the fascination of this strategy was demonstrated by stereodivergent synthesis of bioactive natural products hyperolactones B, C, and their epimers. A possible catalytic model was proposed to explain the origin of the asymmetric induction. Stereodivergent construction of adjacent quaternary-quaternary stereocenters remains a formidable synthetic challenge. Here, the authors report a nickel-catalyzed enantioselective dearomatization Claisen rearrangement leading to vicinal all-carbon stereocentres and apply it to the stereodivergent synthesis of bioactive hyperolactones.

Intermolecular addition of enols and enolates to unactivated alkynes was proved to be a simple and powerful method for carbon-carbon bond formation. Up to date, a catalytic asymmetric version of alkyne with 1,3-dicarbonyl compound has not been realized. Herein, we achieve the catalytic asymmetric intermolecular addition of 1,3-dicarbonyl compounds to unactivated 1-alkynes attributing to the synergistic activation of chiral N , N ′-dioxide-indium(III) or nickel(II) Lewis acid and achiral gold(I) π-acid. A range of β-ketoamides, β-ketoesters and 1,3-diketones transform to the corresponding products with a tetra-substituted chiral center in good yields with good e.r. values. Besides, a possible catalytic cycle and a transition state model are proposed to illustrate the reaction process and the origin of chiral induction based on the experimental investigations. Although enols and enolates addition to unactivated alkynes is used for carbon-carbon bond modification a catalytic asymmetric alkyne with 1,3-dicarbonyl compound has been elusive. Here, the authors achieve this using the synergistic activation of chiral N , N ′-dioxide-indium(III) or nickel(II) Lewis acid and achiral gold(I) π-acid.”

Decarbonization has become an urgent affair to restrain global warming. CO2 hydrogenation coupled with H2 derived from water electrolysis is considered a promising route to mitigate the negative impact of carbon emission and also promote the application of hydrogen. It is of great significance to develop catalysts with excellent performance and large-scale implementation. In the past decades, metal–organic frameworks (MOFs) have been widely involved in the rational design of catalysts for CO2 hydrogenation due to their high surface areas, tunable porosities, well-ordered pore structures, and diversities in metals and functional groups. Confinement effects in MOFs or MOF-derived materials have been reported to promote the stability of CO2 hydrogenation catalysts, such as molecular complexes of immobilization effect, active sites in size effect, stabilization in the encapsulation effect, and electron transfer and interfacial catalysis in the synergistic effect. This review attempts to summarize the progress of MOF-based CO2 hydrogenation catalysts up to now, and demonstrate the synthetic strategies, unique features, and enhancement mechanisms compared with traditionally supported catalysts. Great emphasis will be placed on various confinement effects in CO2 hydrogenation. The challenges and opportunities in precise design, synthesis, and applications of MOF-confined catalysis for CO2 hydrogenation are also summarized.

Liver cancer is a significant global health concern, prompting the search for innovative therapeutic solutions. Yadanziolide A (Y-A), a natural derivative of Brucea javanica, has emerged as a promising candidate for cancer treatment; however, its efficacy and underlying mechanisms in liver cancer remain incompletely understood. In this study, we conducted a comprehensive evaluation of Y-A’s effects on liver cancer cells using a range of in vitro assays and an orthotopic liver cancer mouse model. Our findings reveal that Y-A exerts dose-dependent cytotoxic effects on liver cancer cells, significantly inhibiting proliferation, migration, and invasion at concentrations ≥ 0.1 μM. Furthermore, Y-A induces apoptosis, as evidenced by increased apoptotic cell populations and apoptosome formation. In vivo studies confirm that Y-A inhibits tumor growth and reduces liver damage in mouse models. Mechanistically, Y-A targets the TNF-α/STAT3 pathway, inhibiting STAT3 and JAK2 phosphorylation, thereby activating apoptotic pathways and suppressing tumor cell growth. These results suggest that Y-A has promising anticancer activity and potential utility in liver cancer therapy.

Oxidative dehydrogenation of propane is a promising technology for the preparation of propene. Boron-based nonmetal catalysts exhibit remarkable selectivity toward propene and limit the generation of CO x byproducts due to unique radical-mediated C–H activation. However, due to the high barrier of O-H bond cleavage in the presence of O 2 , the radical initialization of the B-based materials requires a high temperature to proceed, which decreases the thermodynamic advantages of the oxidative dehydrogenation reaction. Here, we report that the boron oxide overlayer formed in situ over metallic Ni nanoparticles exhibits extraordinarily low-temperature activity and selectivity for the ODHP reaction. With the assistance of subsurface Ni, the surface specific activity of the BO x overlayer reaches 93 times higher than that of bare boron nitride. A mechanistic study reveals that the strong affinity of the subsurface Ni to the oxygen atoms reduces the barrier of radical initiation and thereby balances the rates of the BO-H cleavage and the regeneration of boron hydroxyl groups, accounting for the excellent low-temperature performance of Ni@BO x /BN catalysts. The working temperature of boron-based catalysts reduces their thermodynamic advantages in the oxidative dehydrogenation of propane (ODHP). Here the authors demonstrate encapsulated Ni nanoparticles as effective subsurface promoters to enhance the low temperature activity and selectivity of the boron oxide overlayer in ODHP.

Stimulated reservoir volume is an effective stimulation measure and creates a complex fracture network, but the description and characterization of fracture network are very difficult. Well test analysis is a common method to describe the fracture network, and it is the key to build a proper interpretation model. However, most published works only consider the shape of the fractured area or the stress sensitivity effect, and few works take both factors into account. In this paper, based on reservoir properties and flow law after a stimulated reservoir volume, an interpretation model is established with an arbitrary shape of the fractured area and stress sensitivity effect of different flow areas. The model is solved to conduct the pressure response using Laplace transform, point source function, and boundary element theory. The influence of fractures' parameters and stress sensitivity effect is analyzed on the pressure behavior. Results from this study show that the special flow regimes for a horizontal well with a stimulated reservoir volume are (1) bilinear flow dominated by hydraulic fractures, (2) linear flow dominated by formation around the hydraulic fractures, (3) crossflow from a matrix system to the fractured area, and (4) radial flow control by properties of the fractured area. Parameters of hydraulic fractures mainly affect the early stage of pressure behavior. On the contrary, the stress-sensitive effect mainly affects the middle and late stages; the stronger the stress sensitivity effect is, the more obvious the effect is. The findings of this study can help for better understanding of the fracture network in a tight oil reservoir with a stimulated reservoir volume.