Jun Ren

Jun Ren
Taiyuan University of Technology · State Key Laboratory of Clean and Efficient Coal Utilization

Prof.

About

98
Publications
12,739
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1,586
Citations
Citations since 2016
52 Research Items
1359 Citations
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
Additional affiliations
July 1998 - present
Taiyuan University of Technology
Position
  • Professor

Publications

Publications (98)
Article
A series of copper catalysts with loading less than 1.0 wt% supported on super activated carbon (SAC, 2403 m²·g⁻¹) as well as commercial activated carbon (AC, 1297 m²·g⁻¹) were produced by the wet-impregnation process and applied in methanol oxidative carbonylation to generate dimethyl carbonate (DMC). The 0.5Cu/SAC catalyst showed highly dispersed...
Article
Zn-doped Cu(111) alloy (Cu3Zn(111)) and Cu(111) surfaces were built using density functional theory (DFT) calculations to investigate the role of the Zn promoter in the methyl formate (MF) synthesis by the direct dehydrogenation of methanol. The rate determining step (RDS) of the MF synthesis is the dehydrogenation of CH3O to CH2O on both the Cu3Zn...
Article
Methyl glycolate (MG) is a high value-added chemical intermediate and widely used in the fields of medicine, chemical industry, fodder and dyes. A series of CuAg/SiO2 catalysts were prepared by sol-gel method for hydrogenation of dimethyl oxalate to MG. The structure of catalysts was characterized by XRD, N2-physical adsorption, FT-IR, TEM, H2-TPR,...
Article
Electrochemical reduction of CO2 to valuable chemicals using electricity from renewable sources is a promising approach to realize the carbon cycle. Here, a novel bimetallic nitrogen-doped carbon catalyst (M-N-C, where M denotes the metal) CoCu–N–C electrocatalyst has been synthesized by pyrolyzing a copper-doped cobalt(II) acetate–phenanthroline c...
Article
MCo2O4 (M = Co, Cu, Ni or Zn) spinel catalysts have been prepared using a chemical co-precipitation method and applied in toluene combustion. The physicochemical properties of the MCo2O4 catalysts was discussed to explore the impact of substitution on the tetrahedral A-site ions. The results of the activity evaluation show that the catalytic perfor...
Article
CuZn/SiO2 lamellar catalysts are obtained through the introduction of zinc oxide with different amount to Cu/SiO2 prepared by the ammonia-evaporation method and investigated for the dehydrogenation of methanol to methyl formate. The 20CuZn/SiO2 catalyst showed the best catalytic activity with a methanol conversion of 44.5% and a selectivity to meth...
Article
Full-text available
A series of Ni-Al2O3 catalysts with attractive catalytic activity and thermal stability have been developed via a facile hydrolysis-precipitation technique (xNiAl-HP, x representing the weight percentage of NiO). Based on the high nickel active surface area, good dispersion of NiO and high content of α- and β1-type NiO, outstanding CO conversion (9...
Article
N-doped hierarchical porous carbon nanosheets-supported copper catalysts (Cu/NCNS-x) were fabricated to solve the problem of deactivation caused by the leaching, agglomeration and oxidation of Cu nanoparticles (NPs) in the dimethyl carbonate (DMC) synthesis. The optimal Cu/NCNS-12 exhibited superb activity and stability without obvious deactivation...
Article
Full-text available
Co3O4 nanorods with diameters of ~0.15 μm and lengths of ~1 μm were prepared using a hydrothermal method via the assembly of microcrystals and tested in the catalytic oxidation of toluene. The catalytic performance of Co3O4 nanorods was improved by the addition of Ag at various concentrations, and the 7% Ag/Co3O4 catalyst achieves a toluene convers...
Article
Electrocatalytic water splitting is one of the most prospective technology for hydrogen production. Molybdenum disulfide (MoS2), as one of the most promising non-noble metal electrocatalysts, suffers from the disadvantages of limited catalytic sites and weak conductivity which urgently needs to be further optimized. Herein, the C3N4-Ti4O7-MoS2 hete...
Article
Stable and efficient Cu/SBA-15 and xCuZn/SBA-15 (x = 5, 10 and 15) in methanol dehydrogenation to methyl formate (MF) are prepared through a double-solvent impregnation (DI) method. Among all catalysts, 10CuZn/SBA-15 shows the highest catalytic performance with selectivity to MF about 88.1 % and methanol conversion of 31.1 %, which is attributed to...
Article
Wrapping metal nanoparticles (NPs) in graphene shells has emerged as a promising strategy to design highly active and stable catalysts. A facile direct co-pyrolysis approach was proposed to prepare a carbon-supported nitrogen-doped graphenecoated copper NP composite ([email protected]/C) to catalyze the oxidative carbonylation of methanol to dimeth...
Article
CeO2 aerogel (CeO2-A), nanorod (CeO2-R) and nanoflake (CeO2-F) were prepared via sol-gel, hydrothermal and coprecipitation methods, respectively. The effect of morphology and structure of CeO2 on the catalytic performance in toluene combustion reaction was investigated based on structure analysis provided by characterization. The results revealed t...
Article
A series of Ni/ZrO2 catalysts was prepared by the impregnation method with modification of the morphology of ZrO2 support as well as the impregnation procedure and tested for CO2 methanation. The catalysts supported on the ZrO2 nanosheets displayed superior catalytic performance as compared with that on ZrO2 nanoparticles, which could be mainly att...
Article
A group of ternary LaxCe1-xO2-x/2 nanorods with varying La/Ce ratios have been prepared by the hydrothermal strategy and further used to synthesize supported nickel catalysts for CO methanation. The optimal Ni/La0.15Ce0.85O1.925 catalyst showed remarkably improved activity and excellent resistance against coke formation compared with Ni/CeO2. The c...
Article
The hydrogenation of methyl acetate (MA) is a crucial step to obtain ethanol from coal‐syngas indirectly. In this paper, boron doped carbon aerogel (BCAs) has been prepared successfully and applied as support for copper‐base catalyst due to its unique physicochemical properties. The influence of boron on copper‐based catalysts Cu/xBCAs (x=1, 3, 5)...
Article
In this study, tungsten oxide with a high specific surface area was fabricated using a nanocasting technique and used to prepare support for nickel catalysts for CO methanation. Additionally, Mg was further introduced as a promoter for tuning the catalytic performance. The 25Ni/WO3 catalyst demonstrated a relatively high CO conversion, but a poor C...
Article
ZrO2 is known as a prospective catalyst for the direct synthesis of dimethyl carbonate (DMC) from CO2 and methanol, which is important for CO2 utilization and green chemicals production. To identify the relationship between catalytic activity and surface acid–base properties, here, hydroxylated tetragonal (t) and monoclinic (m) zirconia are explore...
Article
Exfoliation of graphene oxide (GO) via thermal expansion is regarded as the most promising approach to obtain few-layer graphene (FLG) in bulk. Herein, we introduce an efficient strategy for improving the exfoliation process by adding a tiny amount of lithium nitrate in the precursors, in which the removal of oxygen-containing functional groups is...
Article
A rational approach for optimization of cobalt based catalysts suitable for VOCs combustion is to modulate the pore structure and to increase the dispersion of active species. In this paper, we prepared CeO2–CoOx composite aerogels with a continuous porous structure using an epoxide-initiated gelation process and evaluated in the catalytic combusti...
Article
A catalytic non-carbon composite composed of molybdenum disulfide (MoS2) and conducting Magnéli phase Ti4O7 is firstly synthesized by a facile hydrothermal method. The MoS2/Ti4O7 composite catalyst shows significantly improved hydrogen evolution reaction (HER) activity in 0.5 M H2SO4 especially at high overpotentials mainly due to the fast electron...
Article
Full-text available
A series of three-dimensional (3D)-interconnected hierarchical porous carbons (HPCs) were prepared through a “leavening” strategy. α-Cellulose and NaHCO3 were used as a raw material and foaming agent, respectively, to support copper catalysts (Cu/HPC) for dimethyl carbonate (DMC) synthesis by the oxidative carbonylation of methanol. The calcination...
Article
Traditional industrial methanation of coke oven gas (COG) to produce natural gas generally requires three or more adiabatic reactors, thus resulting in a long process flow, rapid deactivation of catalyst and high investment cost. Herein, a new methanation process of COG (denoted as NCtSNG) over the Ni-Ce/γ-Al2O3 catalyst was proposed, wherein a tub...
Article
The development of high-performance copper (Cu)-based catalysts is critical to achieve the industrial hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG). To understand the effect of Cu valence state on MG formation, a theoretical study was performed over Cu⁺-perfect, Cu⁺-defective, Cu⁰, and Cu⁰/Cu⁺ catalysts by density-functional theo...
Article
Full-text available
The resistance to sintering of Ni/Al2O3 catalysts with different additives for methanation reaction was modeled and predicted by data mining. In the screening, the resistance to sintering of Na, Ca, Ce, Mg, La, Cu, Zn, Zr, In, Mo, and Ti promoted Ni/Al2O3 catalyst were measured in terms of the increased rate of the size of the metallic nickel parti...
Article
Methyl acetate (MA) hydrogenation is crucial in the indirect ethanol synthesis through syngas (CO+H2). In our work, activated carbon aerogels supported copper (Cu-ACAs) catalysts have been prepared by a conventional impregnation method. The surface area and functional groups of the ACA soared after KOH activation. The highest surface area of the AC...
Article
The reaction mechanism of dimethyl carbonate (DMC) synthesis from methanol and CO2 over cubic (c), tetragonal (t), and monoclinic (m) ZrO2 phases have been investigated by density functional theory (DFT) calculations. The two possible reaction routes have been examined on the three most stable surfaces of zirconia, namely the dry perfect c-ZrO2(1 1...
Article
Graphitic carbon nitride (g-C3N4) supported CoOx catalysts were prepared by impregnation method and comprehensively characterized by XRD, N2 physisorption, TEM, H2-TPR, and XPS. The catalytic performance tested by catalytic combustion of toluene indicate that 10% CoOx/g-C3N4 catalyst exhibits the highest activity, achieving a toluene conversion of...
Article
It is a big challenge to improve the stability and anti-coking abilities of catalyst in high temperature CO methanation reaction. To address the issue, SiC was chose as the support, and Ce was used as a promoter to prepare supported Ni catalysts for CO methanation. A long-term high temperature stability evaluation experiment was carried out at 600...
Article
Nitrogen-doped graphene (NG) has recently attracted much interest because of its ability to fix the metal nanoparticles (NPs). In this study, NG materials with a nitrogen content of 4.5–7.6 wt% were prepared by hydrothermal method and then used to support Cu catalysts for dimethyl carbonate (DMC) synthesis via the oxidative carbonylation of methano...
Article
Full-text available
Active catalysts that were prepared by dispersing copper (Cu) nanoparticles on potassium hydroxide (KOH)-activated carbon aerogels (ACAs) were investigated in the synthesis of dimethyl carbonate (DMC) by vapor-phase oxidative carbonylation of methanol. The effect of mesopores and surface oxygen-containing groups (OCGs) including C = O, COOH and OH...
Article
Reduced graphene oxide (rGO) intercalated with a carbon black (CB) supported copper catalyst (Cu/rGO-CB) was employed in the synthesis of dimethyl carbonate (DMC) via liquid-phase oxidative carbonylation of methanol. The conversion of methanol and the space-time yield of DMC (STYDMC) over Cu/rGO-CB reached 5.6% and 2757 mg/(g h), higher than over a...
Article
Full-text available
A facile way was developed to fabricate yolk-shell composites with tunable Cu cores encapsulated within hollow carbon spheres (Cu@C) with an average diameter about 210 nm and cavity size about 80 nm. During pyrolysis, the confined nanospace of hollow cavity ensures that the nucleation-and-growth process of Cu nanocrystals take place exclusively ins...
Article
The synthesis of dimethyl carbonate (DMC) by oxidative carbonylation of methanol on atomic Cu supported on N-doped graphene (Cu1/NG) was explored by density-functional theory. The configurations with which the Cu atom is anchored to pyridinic- (Cu/PNG), graphitic- (Cu/GNG) and amino-N (Cu/ANG) doped graphene have been systematically investigated an...
Article
A critical aspect in the improvement of the catalytic performance of Cu-based catalysts for the synthesis of dimethyl carbonate (DMC) is the development of an appropriate support. In this work, nitrogen-doped hollow carbon spheres (NHCSs), with 240 nm average diameter, 17 nm shell thickness, uniform mesoporous structure and a specific surface area...
Article
In order to improve the catalytic activity, the screening of optimal potential additives to Ni/Al2O3 catalysts for CO methanation was performed by data mining techniques with a combination of principal component analysis, K-means algorithm and Gaussian process regression (GPR). Based on tremendous amount data from previous studies, 63 elements excl...
Article
The mechanism for dimethyl carbonate (DMC) synthesis by oxidation carbonylation of methanol on a single-atom Cu1/graphene catalyst was investigated by density-functional theory calculations. Carbon vacancies in graphene can significantly enhance the interaction between Cu atoms and graphene supports, and provide an increased transfer of electrons f...
Article
Ordered mesoporous silica-carbon (MSC) nanocomposites with homogeneously distributed networks were synthesized by the triconstituent co-assembly method and used as supports of Cu catalysts for dimethyl carbonate (DMC) synthesis. The introduced silica contributes to the considerably increased pore size (∼5.8 nm), the enhanced metal-support interacti...
Article
Catalysts composed of Ni supported on SiO2/TiO2 composite oxides (ST) with different Si/Ti molar ratios have been prepared by an ultrasonic impregnation method and used in CO methanation. Experimental results show that the ST systems have large specific surface area, large pore volume, and offer suitable metal–support interactions, thereby facilita...
Article
The mechanism of methane synthesis from syngas on a Ni4/t-ZrO2(101) surface, as well as the effect of oxygen vacancies and hydroxyl groups, was systematically investigated using density functional theory. Our results showed that CO hydrogenation to a CHO intermediate was more favorable than direct CO dissociation on both perfect and defect surfaces...
Article
Copper catalysts with a loading of 16.7 wt%, supported on activated carbon (AC) with the addtion of La or Zr, have been prepared by microwave heating methods and tested for the oxidative carbonylation of methanol to dimethyl carbonate (DMC). X-ray diffraction (XRD, temperature-programmed reduction (TPR), XPS), and scanning electron micrographs (SEM...
Article
Ni-based catalysts, which are widely used, have produced promising results for methane formation from syngas. The key to rational design of catalysts and corresponding technological parameters is an understanding of the underlying mechanism of CO methanation at the molecular level. In the present study, the mechanism of CO methanation on Ni (111) a...
Article
Novel activated carbon (AC)-supported highly dispersed hollow Cu nanoparticles (NPs) (Cu/AC) with exposed {1 1 1} facets have been prepared by microwave irradiation for the synthesis of dimethyl carbonate (DMC). In particular, Cu NPs with a large cavity diameter of 35 nm are formed after irradiation from room temperature to 360 °C within a mere 8 m...
Article
单原子催化体系的成功构建将催化领域研究深入到更小的尺度范围,不仅可以从原子层次认识复杂的多相催化反应,而且由于其优越的催化性能在工业催化中具有巨大的应用潜能。本文基于近年来国内外研究者在单原子催化领域的研究工作,总结归纳了单原子催化剂的性能特征,介绍了单原子催化剂的制备手段、表征技术、理论研究及其在CO 氧化、选择性加氢和光电催化等反应中的应用研究进展,分析了单原子催化剂特殊的电子结构对催化性能和反应机理的影响及其作用机制,指出了单原子催化体系在研究领域取得的突破与不足,对于深刻认识单原子催化的概念与原理、完善实验与理论研究方法、拓展应用范围和尽早实现工业应用提出了建议与展望。
Article
Ni/SBA-15 catalysts with various promoters (V, Ce, and Zr) were prepared by an ultrasonic coimpregnation method and used in CO methanation. The addition of promoters played a significant role in improving the catalytic activity of the Ni/SBA-15 catalyst. This improvement could be explained by changes in the valences of the V and Ce promoter species...
Article
The different mechanisms of CO2 methanation on Ni(111) surfaces have been investigated by density functional theory with and without the formation of CO as an intermediate. The most stable adsorption configurations of all reaction species (O, OH, CO, CH, CH2, CH3, CH4, HCOO, C(OH)2, CH2O, etc.) in three paths of CO2 methanation adsorbed on the Ni(1...
Article
Ni/ZrO2 catalysts are widely used in many reactions such as CO/CO2 methanation and reforming of acetic acid. The kind of ZrO2 phase plays a vital role in the catalytic properties of Ni/ZrO2 catalysts that depend on the interface between zirconia and supported Ni particles. Periodic density functional theory was applied to systematically investigate...
Article
Activated carbon-supported copper catalysts (Cu/AC) were prepared by impregnation of AC support with aqueous copper (II) nitrate solutions and subsequent microwave carbothermic reduction under different irradiation conditions. This was done to investigate the effect of the valence of copper on the vapor-phase oxidative carbonylation of methanol to...
Article
The Cu/AC catalysts were prepared by impregnation of activated carbon with copper nitrate followed by microwave heating in vacuum. They were subsequently tested with the oxidative carbonylation of methanol to dimethyl carbonate. X-ray diffraction, N2 adsorption, Temperature-programmed reduction, X-ray photoelectron spectroscopy and scanning electro...
Article
The activity and selectivity of heterogeneous catalysts can be significantly improved by dispersion of another active component in the metal substrate. The impact of Rh promoter on the formation of dimethyl carbonate (DMC) via oxidative carbonylation of methanol on Cu–Rh/AC (activated carbon) catalyst was investigated by density functional theory c...
Article
Combustion characteristics of coal gangue under O2/N2 mixtures with different O2 concentrations and coal mine methane (CMM) conditions were investigated by using thermogravimetric analysis (TGA) and tube reactor tests. Calculation results for the combustion characteristic parameters show that ignition temperature, burnout temperature, and peak temp...