Search

Mesoporous carbon (MPC) nanomaterials, with large specific surface area, excellent conductivity and stability, and effective mass transfer are beneficial for use as catalyst support in electrochemical oxygen reduction reaction (ORR) for fuel cell applications. However, MPC utilization was limited by difficulties in loading catalyst nanoparticles within the MPC pores while simultaneously controlling critical particle parameters such as size and distribution. In this study we report a new vacuum impregnation method combined with solid-state chemistry synthesis for preparing highly active ORR catalyst nanoparticles on MPC supports. We confirm the effectiveness of this method by synthesizing octahedral Pt2CuNi nanoparticles on hydrophilic MPC with an even particle distribution in the MPC pores. We also demonstrate the capability of this method in controlling the particle size and morphology by adjusting the synthesis parameters. The synthesized catalysts exhibited excellent ORR activity and promising durability, which proves the goodness of using MPC support in ORR electrocatalysis. The findings offer a new methodology for synthesizing nanoparticles in MPC pores with parameter control and provide an intriguing strategy to develop new ORR catalysts using MPC support structure.

Methanol synthesis via CO2 hydrogenation has attracted intensive research efforts, but is challenged with development of active and selective catalyst materials that would allow the reaction occurs under milder conditions and being economically more viable. Herein we report the use of bifunctional active sites and their synergy in promoting CO2 hydrogenation kinetics and selectivity. A series of Cu-In-Zr-O mixed oxide nanomaterials containing Cu and defective In2O3 active sites were synthesized and studied for the catalytic properties. Significantly higher CO2 conversion and methanol selectivity were achieved using the Cu-In-Zr-O compared to its non-copper counterpart In-Zr-O, revealing synergy between the two active sites. Insights into the mechanism and functionality of the two actives in CO2 hydrogenation catalysis were obtained with in situ DRIFTS study. A formate-methoxy-methanol pathway and the possible rate-limiting steps were discovered. The excellent selectivity property of the Cu-In-Zr-O was attributed to strong adsorption of CO2 to defective In2O3, which creates a large energy barrier that suppresses CO2 dissociation into CO. The promotion in CO2 hydrogenation kinetics was attributed to cooperation between the bifunctional active sites, with Cu sites adsorb and provide active hydrogen atoms that hydrogenate adsorbed CO2 at adjacent defective In2O3 sites. The findings confirmed synergy between bifunctional sites in CO2 hydrogenation catalysis and provided a new concept in development of active and selective catalyst materials.

With clean water availability raising a great technological and social challenge, saltwater desalination has become a key strategic solution. Herein, we report a nickel phthalocyanine tetrasulfonic acid tetrasodium salt (NiPcTATS)-based redox flow desalination cell (RFDC) that allows safe, efficient and continuous water-salt separation. With the new, water-soluble NiPcTATS/NiPcTATS+ redox couple as electrolyte, the RFDC effectively desalinates saltwater and achieves a high average salt removal rate of 3.11 gNaCl/(molNiPcTATS·h) and a low energy consumption of 15.0 kJ/molNaCl at 0.5 V cell voltage. The cell exhibits excellent reversibility and durability for long-term operation, benefiting from the fast-redox kinetics and chemical stability of the redox couple. Efficient solar-driven RFDC for water desalination is demonstrated by powering the cell with a solar panel. This RFDC method provides a low-cost, efficient and safe strategy to purify saltwater, and the findings with NiPcTATS-based redox couple offer new opportunities of utilizing metal phthalocyanines and derivatives in water desalination research.

A novel methodology of maximum information entropy theory combined with structure oriented lumping (SOL) and Monte Carlo (MC) method was developed to simulate the feedstock for secondary reactions of fluid catalytic cracking (FCC) gasoline at the molecular level. The SOL method was applied to represent the feedstock configuration framework; a molecular library consisting of a large ensemble of computational molecules was created by stochastically assembling structural increments using MC method; then, the maximum information entropy method (MIEM) was introduced to adjust the mole fractions of the structural increments in the molecular library to achieve a closer matching with the actual analytical characteristics. Three samples of catalytic cracking gasoline from the industrial FCC units of China were used to validate and evaluate the proposed method. The simulation results of the feedstock properties, such as the average molecular weight and the weight fractions of main components including paraffin, olefins, naphthenes and aromatics agreed well with the experimental data.

Polyacrylamide gel electrophoresis (PAGE) is a powerful protein separation technology. Combined with mass spectrometry, it could identify thousands of proteins in proteomics analysis. However, the time-consuming procedure restricts its broad applications in proteomics study. In this work, it was found that high concentration of trypsin did not compromise subsequent phosphopeptide enrichment after in-gel digestion, but could promote the in-gel digestion. Hence, a new, fast and robust digestion method was established. Firstly, 50 μg of HeLa cell protein was separated into 5 fractions by SDS-PAGE, and then the proteins were digested with high concentration trypsin for 30 min. Finally, the phosphopeptides were enriched by Ti-IMAC Tip. After liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, about 2000 phosphorylation sites were identified in the experimental group, while less than 1500 phosphorylation sites were identified in control group. With the aid of high concentration of trypsin, in-gel digestion could be completed within only 30 min, and more phosphorylation site identifications and lower percentage of missed cleavages were acquired than those in control experiments. The experiment results demonstrated that high concentration of trypsin could not only accelerate the in-gel digestion, but also improve the phosphoproteome coverage.

Liquid–liquid equilibrium data for three ternary systems which contain glycerol and its etherification (tert-butylation) products including mono-tert-butyl ethers of glycerol (ME), di-tert-butyl ethers of glycerol (DE) and tri-tert-butyl ether of glycerol (TE) in the temperature range of 343.2–373.2 K under 101.3 kPa were obtained by phase equilibrium experiments. Reliability of the experimental data was verified by Othmer–Tobias equation. The non-random two liquid (NRTL) model was employed to describe the equilibrium compositions, and corresponding binary interaction parameters were estimated by data regression. The modeling results agreed well with measured data. In addition, three UNIFAC based methods were also adapted to model liquid–liquid equilibrium behavior for these systems; however, the predicted results emerged obvious deviation from experimental results.

A novel copolymer of chitosan-g-poly(p-dioxanone) (CGP) was synthesized in bulk by ring-opening polymerization of p-dioxanone (PDO) initiated by the hydroxyl group or amino group of chitosan using SnOct2 as catalyst. The chemical structure was determined by 1H NMR. It was found that the feed ratio of chitosan to PDO had a great effect on the degree of polymerization (DP) and the substitution (DS) of PDO. The thermal stability and crystallization behavior of graft copolymer CGP were closely related to the values of DP and DS. When the resulting copolymer was used as Ibuprofen carrier, the release rate of Ibuprofen decreased compared with that of pure chitosan carrier. The drug release behavior was also influenced by the structure of graft copolymers.