Chunjun Chen

The highly selective aerobic oxidation of cyclohexane to cyclohexanone and cyclohexanol over V2O5@TiO2 under simulated solar light irradiation

The highly selective aerobic oxidation of cyclohexane to cyclohexanone and cyclohexanol (KA-oil) under benign and green conditions is still a challenging topic. In this work, V2O5@TiO2 catalysts were prepared by V species deposited on TiO2 (P25) and characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), and UV-vis diffuse reflectance techniques. The selective aerobic oxidation of cyclohexane was carried out over V2O5@TiO2 catalysts with oxygen as an oxidant under simulated light irradiation. The influences of solvents, metals and mass of V species deposited on TiO2, pressure of oxygen, and reaction time on the reaction were investigated. It was found that the V species deposited on the TiO2 surface was very efficient for the photocatalytic oxidation of cyclohexane under simulated solar light irradiation. More interestingly, the selectivity of the reaction in an acetonitrile/water mixed solvent was much higher than that in other solvents. Under the optimized conditions, the selectivity to KA-oil products could be nearly 100% at a cyclohexane conversion of 18.9%. The possible pathway for the catalytic reaction was proposed.

MoP Nanoparticles Supported on Indium‐Doped Porous Carbon: Outstanding Catalysts for Highly Efficient CO2 Electroreduction

Electrochemical reduction of CO2 into value-added product is an interesting area. MoP nanoparticles supported on porous carbon were synthesized using metal-organic frameworks as the carbon precursor, and initial work on CO2 electroreduction using the MoP-based catalyst were carried out. It was discovered that MoP nanoparticles supported on In-doped porous carbon had outstanding performance for CO2 reduction to formic acid. The Faradaic efficiency and current density could reach 96.5 % and 43.8 mA cm-2 , respectively, when using ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate as the supporting electrolyte. The current density is higher than those reported up to date with very high Faradaic efficiency. The MoP nanoparticles and the doped In2 O3 cooperated very well in catalyzing the CO2 electroreduction.

Synthesis of ethanol from paraformaldehyde, CO2 and H2

Ethanol is an important bulk chemical and alternative fuel that is currently synthesized by catalytic hydration of ethylene or fermentation of foods. CO2 is a cheap and renewable carbon resource. Transformation of CO2 into useful chemicals is an interesting topic in green chemistry. Production of ethanol using CO2 and H2 is a promising route, but the efficiency of the reaction is not satisfactory. In this paper, we propose a protocol to synthesize ethanol from paraformaldehyde, CO2 and H2. The reaction could be efficiently accelerated by a Ru–Co bimetallic catalyst using LiI as the promoter in 1,3-dimethyl-2-imidazolidinone (DMI) under mild conditions. The selectivity of ethanol in total products reached 50.9 C-mol%, which was obviously higher than that of the reported routes. Furthermore, the TOF of ethanol based on Ru metal was as high as 17.9 h−1. To our knowledge, this is the first report on ethanol synthesis from paraformaldehyde, CO2 and H2. A detailed study indicated that the outstanding results of the reaction originated from the synergy of paraformaldehyde hydrogenation, reverse water gas shift reaction and methanol homologation.

Efficient synthesis of acetic acid via Rh catalyzed methanol hydrocarboxylation with CO2 and H2 under milder conditions

Acetic acid is an important bulk chemical and synthesis of acetic acid via methanol hydrocarboxylation with CO2 and H2 is a very promising route. In this work, we studied the reaction over a number of catalytic systems. It was found that Rh2(CO)4Cl2 with 4-methylimidazole (4-MI) as the ligand was very efficient in the presence of LiCl and LiI. Acetic acid began to form at 150 °C. The TOF was as high as 26.2 h−1 and the yield of acetic acid could reach 81.8% at 180 °C. The catalytic system had obvious advantages, such as simplicity, high activity and selectivity, milder reaction conditions, and less corrosiveness. The excellent cooperation of CO and Cl− in Rh2(CO)4Cl2, suitable basicity and aromaticity of the ligand 4-MI, and the hydrogen bonding ability of Cl− were crucial for the outstanding performance of the catalytic system. The control experiments showed that the reaction did not proceed via the CO pathway.

Nanoporous Cu/Ni oxide composites: efficient catalysts for electrochemical reduction of CO2 in aqueous electrolytes

We developed a route to prepare nanoporous Cu/Ni oxide composites. It was discovered that the Cu/Ni oxide composites were very efficient electrocatalysts for CO2 reduction to formate in aqueous electrolytes. The excellent performance resulted mainly from the porous structure, synergistic effect of the two oxides, and low charge transfer resistance.

Efficient electroreduction of CO2 to C2 products over B-doped oxide-derived copper

B-Doped oxide-derived-Cu is a highly efficient electrocatalyst for transformation of CO2 to C2 products. The faradaic efficiency of C2 products could reach 48.2%, with a high current density of 33.4 mA cm−2 at low potentials in 0.1 M KHCO3 electrolyte. The excellent performance of the catalyst is mainly attributed to Cu+ species stabilized by the introduction of B.