Cobalt phthalocyanine (CoPc) anchored on Ti3C2 MXene nanosheets for highly efficient selective catalytic oxidation.

Quinclorac is an important precursor for pharmaceutical, agricultural, and synthetic chemistry. The state-of-the-art synthesis of quinclorac via condensation, chlorination and oxidative hydrolysis often uses homogeneous catalysts and strong acid oxidant agents to promote the catalytic oxidation, which requires huge manpower input for the late-stage purification process and is usually environmentally unfriendly. In this work, we successfully fabricated a stable cobalt phthalocyanine (CoPc) Co-based composite (CoPc/Ti3C2) by anchoring CoPc on the surface of Ti3C2 nanosheets for the selective oxidation of 3,7-dichloro-8-dichloro methyl quinoline (3,7-D-8-DMQ) into quinclorac. More impressively, CoPc/Ti3C2-4.5%-Mn-Br exhibits a high selectivity of 91.8% for the catalytic oxidation of 3,7-D-8-DMQ to quinclorac in acetic acid, with a quinclorac yield of 87.5%, which is approximately 2.46 times higher than that of pristine CoPc-Mn-Br. The obtained heterogeneous catalytic system shows good reusability. Detailed mechanistic investigations reveal that the system works through the free radical mechanism via the formation of Co2+/Co3+ redox cycles. This work provides a new understanding for the stabilization of reaction intermediates and facilitates the design of catalysts for selective catalytic oxidation.

Programmatically Dynamic Microcompartmentation in Coacervate-in-Pickering Emulsion Protocell.

The desire for exploration of cellular functional mechanisms has substantially increased the rapid development of artificial cells. However, the construction of synthetic cells with high organizational complexity remains challenging due to the lack of facile approaches ensuring dynamic multi-compartments of cytoplasm and stability of membranes in protocells. Herein, a stable coacervate-in-Pickering emulsion protocell model comprising a membraneless coacervate phase formed by poly-l-lysine (PLys) and adenosine triphosphate (ATP) encapsulated in Pickering emulsion is put forward only through simple one-step emulsification. The dynamic distribution of intracellular components (coacervates in this protocell model) can be manipulated by changes in temperature or pH. This coacervate-in-Pickering emulsion protocell system exhibits repeatable cycle stability in response to external stimuli (at least 24 cycles for temperature and 3 cycles for pH). By encapsulating antagonistic enzymes into coacervates, glucose oxidase (GOx) and urease as an example, the control of local enzyme concentration is achieved by introducing glucose and urea to adjust the pH value in Pickering emulsion droplets. This hybrid protocell model with programmatically dynamic microcompartmentation and sufficient stability is expected to be further studied and applied in cellular biology, facilitating the development of lifelike systems with potential in practical applications.

Tailoring of Surface Acidic Sites in Co-MoS2 Catalysts for Hydrodeoxygenation Reaction.

CoMo sulfides are typical catalysts for selective hydrodeoxygenation (HDO) of phenolics to aromatics which is important in bio-oil upgrading. However, it is still a challenge to promote the intrinsic activity of Co-MoS2 catalysts. Defect chemistry provides a good option to improve surface reactivity in catalysis. In this work, we report a facile H2O2 etching method to tailor the concentration of surface acidic sites. The molar ratio of H2O2/MoS2 can be altered to tune sulfur defects on the MoS2 surface for stabilizing Co species to form CoMoS active sites. The optimized Co-MoS2-2 catalyst, with the highest concentration of acidic sites, exhibits 3.4 times higher activity than the Co-MoS2-0 sample in the HDO of p-cresol to toluene. It is also found the HDO activity shows a linear relationship with the amount of surface acid (both Lewis and Brønsted acid) over the Co-MoS2-x catalysts. We believe that the understanding of the role of surface acidity would provide new opportunities for the rational design of efficient Co-MoS2 catalysts.

Fabrication of PdZn alloy catalysts supported on ZnFe composite oxide for CO2 hydrogenation to methanol.

The conversion of CO2 to methanol is of great significance for providing a means of CO2 fixation and the development of future fuels. Supported Pd catalysts have been demonstrated to be active for CO2 hydrogenation to methanol and PdZn alloy plays a key role in this reaction. Therefore, using ZnO-enriched support to increase the amount of nanometric PdZn alloy particles on the surface is an effective strategy to develop ideal catalysts. Herein, we fabricated a PdZn alloy catalyst supported on ZnO-enriched ZnFe2O4 spinel for efficient CO2 hydrogenation to methanol. The amount of formed PdZn alloy and catalyst structure influenced by ZnO concentration on ZnFe2O4 were explored to obtain the best Pd-Z1FO catalyst, which achieves a methanol space-time yield (STY) of 593 gkgcat-1h-1 (12 ggPd-1h-1) with CO2 conversion of 14% under reaction conditions of 290 °C, 4.5 MPa and 21600 mLg-1h-1. Furthermore, the amount of exposed PdZn alloy sites were measured by using CO-pulse chemisorption and we find a linearity between methanol production rate and PdZn alloy sites.

A tunable metal-polyaniline interface for efficient carbon dioxide electro-reduction to formic acid and methanol in aqueous solution.

It is reported that metals on polyaniline (PANI) prepared by a simple method can exhibit excellent activity in the electro-reduction of CO2 to HCOOH or CH3OH due to tunable properties: N atoms on PANI capture CO2 through a strong Lewis acid-base interaction while Pd atoms, amongst Pd, Pt, and Cu studied, facilitate the fastest proton and electron transfers along PANI to the CO2 trapped sites to give rise to the best HCOOH yield in a highly cooperative manner.

Hydrazine-Assisted Liquid Exfoliation of MoS2 for Catalytic Hydrodeoxygenation of 4-Methylphenol.

A simple but effective method to exfoliate bulk MoS2 in a range of solvents is presented for the preparation of colloid flakes consisted of one to a few molecular layers by application of ultrasonic treatment in N2 H4 . Their high yield in solution and exposure of more active surface sites allows the synthesis of corresponding solid catalysts with remarkably high activity in hydrodeoxygenation of 4-methylphenol and this method can also be applied to other two dimensional materials.

In situ facile synthesis of Ru-based core-shell nanoparticles supported on carbon black and their high catalytic activity in the dehydrogenation of amine-boranes.

Well-dispersed core-shell Ru@M (M=Co, Ni, Fe) nanoparticles (NPs) supported on carbon black have been synthesized via a facile in situ one-step procedure under ambient condition. Core-shell Ru@Co NPs were synthesized and characterized for the first time. The as-synthesized Ru@Co and Ru@Ni NPs exhibit superior catalytic activity in the hydrolysis of ammonia borane compared with their monometallic and alloy counterparts. The Ru@Co/C NPs are the most reactive, with a turnover frequency (TOF) value of 320 (mol H 2 min(-1)) molRu (-1) and activation energy (Ea) of 21.16 kJ mol(-1). Ru@Ni/C NPs are the next most active, whereas Ru@Fe/C NPs are almost inactive. Additionally, the as-synthesized NPs supported on carbon black exhibit higher catalytic activity than catalysts on other conventional supports, such as SiO2 and γ-Al2O3.

Shape selective plate-form Ga(2)O(3) with strong metal-support interaction to overlying Pd for hydrogenation of CO(2) to CH(3)OH.

A stronger metal-support interaction between Pd and plate-form Ga(2)O(3) nanocrystals covered with the predominant 002 surface than other Ga(2)O(3) surfaces is found, which gives higher methanol yield in catalytic CO(2) hydrogenation.

Temperature and solvent-dependent morphological sol gel transformation: an in situ microscopic observation.

A thermoreversible self-assemble process from gel (fiber) to sol (vesicle) state in the system alkylamine-ethylene glycol is for the first time monitored by in situ polarized optical microscopy, XRD, (1)H NMR, SEM, SAXRD, FTIR and drop shape analysis. It is found that the solvent molecules are intercalated with alkylamine molecules to form the organogel and vesicle structures. A model based on structural transformation with respect to these alkylamine gelator-solvent assembles is therefore proposed.

Poly(methyl methacrylate)-graft-oligoamines as low cytotoxic and efficient nonviral gene vectors.

A series of poly(methyl methacrylate)-graft-oligoamines (PMMA-g-oligoamines), including PMMA-g-DETA, PMMA-g-TETA and PMMA-g-TEPA, were synthesized through aminolysis of the PMMA with diethylenetriamine, triethylenetetramine and tetraethylenepentamine. Agarose gel retardation assay indicated that PMMA-g-oligoamines had good binding capability with plasmid DNA, and the binding capability increased with increasing length of oligoamines and content of nitrogen (N%). The results of particle size, zeta potential and morphology observation further showed that the PMMA-g-oligoamines could condense DNA efficiently and the PMMA-g-oligoamine/DNA complexes were uniform nanospheres. The in vitro cell viability indicated that PMMA-g-oligoamines were less toxic than 25 kDa PEI, though the cytotoxicity of PMMA-g-oligoamines increased slightly with increasing length of oligoamines as well as the N% of PMMA-g-oligoamines. The transfection efficiency of PMMA-g-oligoamines/DNA complexes in 293 T and HeLa cells demonstrated that PMMA-g-oligoamines could transfect cells efficiently with increasing the length of oligoamines, especially PMMA-g-TEPA with highest N%, and showed similar transfection capability as 25 kDa PEI. The cellular uptake study showed that the distribution of YOYO-1 labeled DNA in the cytoplasm and nuclei increased gradually with increasing length of oligoamines.

The effect of additives on the water solubilization capacity and conductivity in n-pentanol microemulsions.

The influence of additives such as sodium salicylate and sodium chloride on the water solubilization capacity of AOT in n-pentanol solutions has been investigated. The water solubilization capacity is enhanced by sodium salicylate and decreased by sodium chloride. The percolation behavior of the water/AOT/n-pentanol system is studied by modifying the water concentration and temperature. No percolation threshold induced by water or temperature is detected either in the absence or in the presence of additives. The values of ln sigma have a linear correlation with temperature in the range of 5-40 degrees C. The activation energy is also estimated and discussed.