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ZnZr/HZSM-5 as efficient catalysts for alkylation of benzene with carbon dioxide

《化学科学与工程前沿(英文)》 2023年 第17卷 第4期   页码 404-414 doi: 10.1007/s11705-022-2215-6

摘要: Alkylation of benzene with carbon dioxide and hydrogen to produce toluene and xylene could increase the added-value of surplus benzene as well as relieve environmental problems like green-house effect. In this work, the alkylation benzene with carbon dioxide and hydrogen reaction was proceeded by using the mixture of zinc-zirconium oxide and HZSM-5 as bifunctional catalyst. The equivalent of Zn/Zr = 1 displays the best catalytic performance at 425 °C and 3.0 MPa, and benzene conversion reaches 42.9% with a selectivity of 90% towards toluene and xylene. Moreover, the carbon dioxide conversion achieves 23.3% and the carbon monoxide selectivity is lower than 35%, indicating that more than 50% carbon dioxide has been effectively incorporated into the target product, which is the best result as far as we know. Combined with characterizations, it indicated that the Zn and Zr formed a solid solution under specific conditions (Zn/Zr = 1). The as-formed solid solution not only possesses a high surface area but also provides a large amount of oxygen vacancies. Additionally, the bifunctional catalyst has excellent stabilities that could keep operating without deactivation for at least 80 h. This work provides promising industrial applications for the upgrading of aromatics.

关键词: carbon dioxide     alkylation of benzene     solid solution catalyst     bifunctional catalyst    

Alkylation of benzene with carbon dioxide to low-carbon aromatic hydrocarbons over bifunctional Zn-Ti/HZSM-5 catalyst

Xiangyu Liu, Yanling Pan, Peng Zhang, Yilin Wang, Guohao Xu, Zhaojie Su, Xuedong Zhu, Fan Yang

《化学科学与工程前沿(英文)》 2022年 第16卷 第3期   页码 384-396 doi: 10.1007/s11705-021-2045-y

摘要: Alkylation of benzene to value-added, high octane number and low toxic toluene and xylenes provides a way to lower benzene content in gasoline pool, and is hence a method to promote fuel quality. On the other hand, CO accumulation in the atmosphere causes global warming and requires effective route for its valorization. Utilization of CO as a carbon source for benzene alkylation could achieve both goals. Herein, alkylation of benzene with CO and H was realized by a series of low-cost bifunctional catalysts containing zinc/titanium oxides (Zn/Ti oxides) and HZSM-5 molecular sieves in a fixed-bed reactor. By regulating and controlling oxygen vacancies of Zn/Ti oxides and the acidities of HZSM-5, benzene conversion and CO conversion reached 28.7% and 29.9% respectively, along with a total selectivity of toluene and xylene higher than 90%. In this process, more than 25% CO was effectively utilized and incorporated into the target products. Moreover, the mechanism of the reaction was analyzed and the course was simultaneously traced. CO was transformed into methanol firstly, and then methanol reacted with benzene generating toluene and xylene. The innovation provides a new method for upgrading of fuels and upcycling the emissions of CO , which is of great environmental and economic benefits.

关键词: carbon dioxide     benzene     alkylation     bifunctional catalyst     mechanism    

Metal phosphonate-derived cobalt/nickel phosphide@N-doped carbon hybrids as efficient bifunctional oxygen

《化学科学与工程前沿(英文)》 2022年 第16卷 第9期   页码 1367-1376 doi: 10.1007/s11705-022-2153-3

摘要: The exploration of efficient bifunctional electrocatalysts for oxygen reduction reaction and oxygen evolution reaction is pivotal for the development of rechargeable metal–air batteries. Transition metal phosphides are emerging as promising catalyst candidates because of their superb activity and low cost. Herein, a novel metal phosphonate-derived cobalt/nickel phosphide@N-doped carbon hybrid was developed by a carbothermal reduction of cobalt/nickel phosphonate hybrids with different Co/Ni molar ratios. The metal phosphonate derivation method achieved an intimately coupled interaction between metal phosphides and a heteroatom-doped carbon substrate. The resultant Co2P/Ni3P@NC-0.2 enables an impressive electrocatalytic oxygen reduction reaction activity, comparable with those of state-of-the-art Pt/C catalysts in terms of onset potential (0.88 V), 4e selectivity, methanol tolerance, and long-term durability. Moreover, remarkable oxygen evolution reaction activity was also observed in alkaline conditions. The high activity is ascribed to the N-doping, abundant accessible catalytic active sites, and the synergistic effect among the components. This work not only describes a high-efficiency electrocatalyst for both oxygen reduction reaction and oxygen evolution reaction, but also highlights the application of metal phosphonate hybrids in fabricating metal phosphides with tunable structures, which is of great significance in the energy conversion field.

关键词: metal phosphonate     cobalt/nickel phosphide     N-doped carbon     oxygen electrochemistry     Zn−air battery    

Modeling nanostructured catalyst layer in PEMFC and catalyst utilization

Jiejing ZHANG, Pengzhen CAO, Li XU, Yuxin WANG

《化学科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 297-302 doi: 10.1007/s11705-011-1201-1

摘要: A lattice model of the nanoscaled catalyst layer structure in proton exchange membrane fuel cells (PEMFC) was established by Monte Carlo method. The model takes into account all the four components in a typical PEMFC catalyst layer: platinum (Pt), carbon, ionomer and pore. The elemental voxels in the lattice were set fine enough so that each average sized Pt particulate in Pt/C catalyst can be represented. Catalyst utilization in the modeled catalyst layer was calculated by counting up the number of facets of Pt voxels where “three phase contact” are met. The effects of some factors, including porosity, ionomer content, Pt/C particle size and Pt weight percentage in the Pt/C catalyst, on catalyst utilization were investigated and discussed.

关键词: catalyst layer     PEM fuel cell     lattice model     Monte Carlo method     catalyst utilization    

Sulfur-deficient CoNi2S4 nanoparticles-anchored porous carbon nanofibers as bifunctional

《化学科学与工程前沿(英文)》 2023年 第17卷 第11期   页码 1707-1717 doi: 10.1007/s11705-023-2308-x

摘要: Water electrolysis technology is considered to be one of the most promising means to produce hydrogen. Herein, aiming at the problems of high overpotential and slow kinetics in water splitting, N-doped porous carbon nanofibers-coupled CoNi2S4 nanoparticles are prepared as bifunctional electrocatalyst. In the strategy, NaCl is used as the template to prepare porous carbon nanofibers with a large surface area, and sulfur vacancies are created to modulate the electronic structure of CoNi2S4. Electron spin resonance confirms the formation of abundant sulfur vacancies, which largely reduce the bandgap of CoNi2S4 from 1.68 to 0.52 eV. The narrowed bandgap is conducive to the migration of valence electrons and decreases the charge transfer resistance for electrocatalytic reaction. Moreover, the uniform distribution of CoNi2S4 nanoparticles on carbon nanofibers can prevent the aggregation and facilitate the exposure of electrochemical active sites. Therefore, the composite catalyst exhibits low overpotentials of 340 mV@100 mA·cm–2 for oxygen evolution reaction and 380 mV@100 mA·cm–2 for hydrogen evolution reaction. The assembled electrolyzer requires 1.64 V to achieve 10 mA·cm–2 for overall water-splitting with good long-term stability. The excellent performance results from the synergistic effect of porous structures, sulfur deficiency, nitrogen doping, and the well-dispersed active component.

关键词: nanoparticle     sulfur vacancy     porous carbon nanofiber     transition metal sulfides     electrolysis    

Oxidant or catalyst for oxidation?

Jianzhi Huang, Huichun Zhang

《环境科学与工程前沿(英文)》 2019年 第13卷 第5期 doi: 10.1007/s11783-019-1158-8

摘要: Manganese oxides (MnOx) have been demonstrated to be effective materials to activate Oxone (i.e., PMS) to degrade various contaminants. However, the contribution of direct oxidation by MnOx to the total contaminant degradation under acidic conditions was often neglected in the published work, which has resulted in different and even conflicting interpretations of the reaction mechanisms. Here, the role of MnOx (as both oxidants and catalysts) in the activation of Oxone was briefly discussed. The findings offered new insights into the reaction mechanisms in PMS-MnOx and provided a more accurate approach to examine contaminant degradation for water/wastewater treatment.

关键词: Peroxymonosulfate     Manganese oxides     Catalyst     Oxidant    

Monte Carlo simulation of the PEMFC catalyst layer

WANG Hongxing, CAO Pengzhen, WANG Yuxin

《化学科学与工程前沿(英文)》 2007年 第1卷 第2期   页码 146-150 doi: 10.1007/s11705-007-0027-3

摘要: The performance of the polymer electrolyte membrane fuel cell (PEMFC) is greatly controlled by the structure of the catalyst layer. Low catalyst utilization is still a significant obstacle to the commercialization of the PEMFC. In order to get a fundamental understanding of the electrode structure and to find the limiting factor in the low catalyst utilization, it is necessary to develop the mechanical model on the effect of catalyst layer structure on the catalyst utilization and the performance of the PEMFC. In this work, the structure of the catalyst layer is studied based on the lattice model with the Monte Carlo simulation. The model can predict the effects of some catalyst layer components, such as Pt/C catalyst, electrolyte and gas pores, on the utilization of the catalyst and the cell performance. The simulation result shows that the aggregation of conduction grains can greatly affect the degree of catalyst utilization. The better the dispersion of the conduction grains, the larger the total effective area of the catalyst is. To achieve higher utilization, catalyst layer components must be distributed by means of engineered design, which can prevent aggregation.

关键词: catalyst utilization     PEMFC     commercialization     Pt/C catalyst     conduction    

Dendritic BiVO4 decorated with MnOx co-catalyst as an efficient hierarchical catalyst for photocatalytic

Jin Yang, Xuelian Liu, Hongbin Cao, Yanchun Shi, Yongbing Xie, Jiadong Xiao

《化学科学与工程前沿(英文)》 2019年 第13卷 第1期   页码 185-191 doi: 10.1007/s11705-018-1713-z

摘要: An appropriate co-catalyst can significantly promote the photocatalytic efficacy, but this has been seldom studied in the visible-light photocatalysis combined with ozone, namely photocatalytic ozonation. In this work, a dendritic bismuth vanadium tetraoxide (BiVO ) material composited with highly dispersed MnO nanoparticles was synthesized, and its catalytic activity is 86.6% higher than bare BiVO in a visible light and ozone combined process. Catalytic ozonation experiments, ultra-violet-visible (UV-Vis) diffuse reflectance spectra and photoluminescence spectra jointly indicate that MnO plays a triple role in this process. MnO strengthens the light adsorption and promotes the charge separation on the composite material, and it also shows good activity in catalytic ozonation. The key reactive species in this process is ·OH, and various pathways for its generation in this process is proposed. This work provides a new direction of catalyst preparation and pushes forward the application of photocatalytic ozonation in water treatment.

关键词: manganese oxide     bismuth vanadium tetraoxide     photocatalytic ozonation     hydroxyl radical     co-catalyst    

Insight into the promotion mechanism of activated carbon on the monolithic honeycomb red mud catalyst

《环境科学与工程前沿(英文)》 2021年 第15卷 第5期 doi: 10.1007/s11783-020-1337-7

摘要:

• Activated carbon was proposed to be an efficient accelerant for molded red mud catalyst.

关键词: NOx     Selective catalytic reduction     Iron-based catalyst     Red mud     Monolithic catalyst     Activated carbon    

Direct synthesis of diphenyl carbonate over heterogeneous catalyst: effects of structure of substitutedperovskite carrier on the catalyst activities

WU Guangwen, JIN Fang, WU Yuxin, ZHANG Guangxu, LI Dinghuo, WANG Cunwen, MA Peisheng

《化学科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 59-64 doi: 10.1007/s11705-007-0012-x

摘要: The perovskite-type compound LaMnO was substituted for the part of La in position A and for the part of Mn in position B by citrate method. The phases were detected by X-ray diffraction. Powder morphologies were scanned by scanning electron microscopy. The valence of atoms was determined by X-ray photoelectron spectroscopy. It was found that the perovskite can form crystal defect and increase the proportion of high valence B element by doping. Active component Pd was loaded on various perovskite supports for synthesis of diphenyl carbonate. The results showed that the activities of catalysts in which supports have crystal defect by substitution were higher. It can be concluded that perovskite with defect structure by doping could lead to the formation of oxygen vacancy where the lattice oxygen became exchangeable with the oxygen gas. Also, this improved the redox process of the carrier by transferring electrons and activities of catalysts.

关键词: photoelectron spectroscopy     diphenyl carbonate     proportion     diffraction     perovskite    

Pd nano-catalyst supported on biowaste-derived porous nanofibrous carbon microspheres for efficient catalysis

《化学科学与工程前沿(英文)》 2023年 第17卷 第9期   页码 1289-1300 doi: 10.1007/s11705-023-2299-7

摘要: Environmental pollution caused by the presence of aromatic aldehydes and dyes in wastewater is a serious global concern. An effective strategy for the removal of these pollutants is their catalytic conversion, possibly to valuable compounds. Therefore, the design of efficient, stable and long-lifetime catalysts is a worthwhile research goal. Herein, we used nanofibrous carbon microspheres (NCM) derived from the carbohydrate chitin present in seafood waste, and characterized by interconnected nanofibrous networks and N/O-containing groups, as carriers for the manufacture of a highly dispersed, efficient and stable Pd nano-catalyst (mean diameter ca. 2.52 nm). Importantly, the carbonised chitin’s graphitized structure, defect presence and large surface area could promote the transport of electrons between NCM and Pd, thereby endowing NCM supported Pd catalyst with high catalytic activity. The NCM supported Pd catalyst was employed in the degradation of some representative dyes and the chemoselective hydrogenation of aromatic aldehydes; this species exhibited excellent catalytic activity and stability, as well as applicability to a broad range of aromatic aldehydes, suggesting its potential use in green industrial catalysis.

关键词: biowaste chitin     nanofibrous     palladium     nano-catalyst     catalysis    

Advanced materials: adsorbent and catalyst for environmental application

Junhua LI, Shubo DENG

《环境科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 301-301 doi: 10.1007/s11783-013-0529-9

Ni-Co bimetallic catalyst for CH

Xiaohong LI, Jun AI, Wenying LI, Dongxiong LI

《化学科学与工程前沿(英文)》 2010年 第4卷 第4期   页码 476-480 doi: 10.1007/s11705-010-0512-y

摘要: A co-precipitation method was employed to prepare Ni/Al O -ZrO , Co/Al O -ZrO and Ni-Co/Al O -ZrO catalysts. Their properties were characterized by N adsorption (BET), thermogravimetric analysis TGA , temperature-programmed reduction (TPR), temperature-programmed desorption (CO -TPD), and temperature-programmed surface reaction (CH -TPSR and CO -TPSR). Ni-Co/Al O -ZrO bimetallic catalyst has good performance in the reduction of active components Ni, Co and CO adsorption. Compared with mono-metallic catalyst, bimetallic catalyst could provide more active sites and CO adsorption sites (C+ CO = 2CO) for the methane-reforming reaction, and a more appropriate force formed between active components and composite support (SMSI) for the catalytic reaction. According to the CH -CO -TPSR, there were 80.9% and 81.5% higher CH and CO conversion over Ni-Co/Al O -ZrO catalyst, and its better resistance to carbon deposition, less than 0.5% of coke after 4 h reaction, was found by TGA. The high activity and excellent anti-coking of the Ni-Co/Al O -ZrO catalyst were closely related to the synergy between Ni and Co active metal, the strong metal-support interaction and the use of composite support.

关键词: Ni-Co bimetallic catalyst     composite support     CH4 reforming with CO2    

Sulfonic acid-functionalized mesoporous silica catalyst with different morphology for biodiesel production

《化学科学与工程前沿(英文)》 2022年 第16卷 第8期   页码 1198-1210 doi: 10.1007/s11705-021-2133-z

摘要: Sulfonic acid functionalized mesoporous silica based solid acid catalysts with different morphology were designed and fabricated. The synthesized materials were characterized by various physicochemical and spectroscopic techniques like scanning electron microscope-energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller surface area, thermogravimetric analysis and n-butylamine acidity. The shape of catalysts particles plays an important role in its activity. The sulfonic acid functionalized mesoporous silica catalysts of spherical shape and the cube shape were assessed for catalytic activity in biodiesel production. The catalytic biodiesel production reaction over the catalysts were studied by esterification of free fatty acid, oleic acid with methanol. The effect of various reaction parameters such as catalyst concentration, acid/alcohol molar ratio, catalyst amount, reaction temperature and reaction time on catalytic activity were investigated to optimize the conditions for maximum conversion. It was sulfonated cubic shape mesoporous silica which exhibited better activity as compared to the spherical shape silica catalysts. Additionally, the catalyst was regenerated and reused up to three cycles without any significant loss in activity. The present catalysts exhibit superior performance in biodiesel production and it can be used for the several biodiesel feedstock’s that are rich in free fatty acids.

关键词: solid acid catalyst     mesoporous silica     sulfonic acid     biodiesel     esterification     oleic acid    

Synthesis of methanol and ethanol over CuZnAl slurry catalyst prepared by complete liquid-phase technology

Wei HUANG, Linmei YU, Wenhui LI, Zhili MA

《化学科学与工程前沿(英文)》 2010年 第4卷 第4期   页码 472-475 doi: 10.1007/s11705-010-0525-6

摘要: A new method, named the complete liquid-phase technology, has been applied to prepare catalysts for methanol synthesis. Its main innovative thought lies in preparing slurry catalysts directly from raw solution. Activity tests indicate that the CuZnAl slurry catalyst prepared by the new method can efficiently catalyze conversion of syngas to ethanol in a slurry reactor, while CO conversion reaches 35.9% and ethanol selectivity is more than 20%, with a total alcohol selectivity of more than 87%. No deactivation was found during the 192 h reaction .

关键词: methanol     slurry     ethanol     complete liquid-phase technology     CuZnAl catalyst    

标题 作者 时间 类型 操作

ZnZr/HZSM-5 as efficient catalysts for alkylation of benzene with carbon dioxide

期刊论文

Alkylation of benzene with carbon dioxide to low-carbon aromatic hydrocarbons over bifunctional Zn-Ti/HZSM-5 catalyst

Xiangyu Liu, Yanling Pan, Peng Zhang, Yilin Wang, Guohao Xu, Zhaojie Su, Xuedong Zhu, Fan Yang

期刊论文

Metal phosphonate-derived cobalt/nickel phosphide@N-doped carbon hybrids as efficient bifunctional oxygen

期刊论文

Modeling nanostructured catalyst layer in PEMFC and catalyst utilization

Jiejing ZHANG, Pengzhen CAO, Li XU, Yuxin WANG

期刊论文

Sulfur-deficient CoNi2S4 nanoparticles-anchored porous carbon nanofibers as bifunctional

期刊论文

Oxidant or catalyst for oxidation?

Jianzhi Huang, Huichun Zhang

期刊论文

Monte Carlo simulation of the PEMFC catalyst layer

WANG Hongxing, CAO Pengzhen, WANG Yuxin

期刊论文

Dendritic BiVO4 decorated with MnOx co-catalyst as an efficient hierarchical catalyst for photocatalytic

Jin Yang, Xuelian Liu, Hongbin Cao, Yanchun Shi, Yongbing Xie, Jiadong Xiao

期刊论文

Insight into the promotion mechanism of activated carbon on the monolithic honeycomb red mud catalyst

期刊论文

Direct synthesis of diphenyl carbonate over heterogeneous catalyst: effects of structure of substitutedperovskite carrier on the catalyst activities

WU Guangwen, JIN Fang, WU Yuxin, ZHANG Guangxu, LI Dinghuo, WANG Cunwen, MA Peisheng

期刊论文

Pd nano-catalyst supported on biowaste-derived porous nanofibrous carbon microspheres for efficient catalysis

期刊论文

Advanced materials: adsorbent and catalyst for environmental application

Junhua LI, Shubo DENG

期刊论文

Ni-Co bimetallic catalyst for CH

Xiaohong LI, Jun AI, Wenying LI, Dongxiong LI

期刊论文

Sulfonic acid-functionalized mesoporous silica catalyst with different morphology for biodiesel production

期刊论文

Synthesis of methanol and ethanol over CuZnAl slurry catalyst prepared by complete liquid-phase technology

Wei HUANG, Linmei YU, Wenhui LI, Zhili MA

期刊论文