ACS Omega
·
2021
·
IF 3.512
Binbin Jin,Ligang Luo,Longfei Xie
The utilization of CO2, as a cheap and abundant carbon source to produce useful chemicals or fuels, has been regarded as one of the promising ways to reduce CO2 emissions and minimize the green-house effect. Previous studies have demonstrated that CO2 (or HCO3–) can be efficiently reduced to formic acid with metal Fe under hydrothermal conditions without additional hydrogen and any catalyst. However, the pathways and kinetics of the autocatalytic CO2 reduction remain unknown. In the present work, the reaction kinetics were carefully investigated according to the proposed reaction pathways, and a phenomenological kinetic model was developed for the first time. The results showed that the hydrothermal conversion of HCO3– into formic acid with Fe can be expressed as the first-order reaction, and the activation energy of HCO3– is 28 kJ/mol under hydrothermal conditions.
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PubMed
高影响因子
ChemSusChem
·
2021
·Vol. 14
·期 13
·2769-2779
·
IF 8.928
Yuning Zhang,Hai Xu,Dongfang Niu,Xinsheng Zhang,Yayun Zhang
Graphical Composite catalyst : Axially grafted pyridine is successfully coupled with SnO 2 nanoparticles to construct the organic-inorganic composite catalyst SnO 2 /Py-CNTO for highly efficient electroreduction of CO 2 . SnO 2 /Py-CNTO delivers an excellent faradaic efficiency (FE) of 96 % for CO 2 ER at −1.29 V RHE where the HCOOH production with 85 % FE dominates, and good stability for 32 h electrolysis. Sn-based electrocatalysts have shown great potential in the future industrial application of CO 2 electroreduction (CO 2 ER) to C 1 products due to their non-toxicity and low price. However, it is a great challenge to fabricate a Sn-based electrocatalytic system with high performance and stability. Herein, grafted pyridine was innovatively coupled with SnO 2 to construct an organic-inorganic composite (SnO 2 /Py-CNTO) for highly efficient CO 2 ER. The detailed studies showed that pyridine and protonated pyridine coexist on the surface of SnO 2 /Py-CNTO, and both play distinctive roles in promoting the selectivity of CO 2 ER. Benefiting from the merits, SnO 2 /Py-CNTO delivered an excellent faradaic efficiency (FE) of 96 % for CO 2 ER at −1.29 V RHE where the HCOOH production with 85 % FE dominated, and good stability for 32 h electrolysis. The theoretical calculations showed that protonated pyridine not only facilitates the CO 2 adsorption and HCOOH desorption, but also significantly reduces the limiting potential for the conversion of CO 2 to HCOOH.
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高影响因子
Catalysts
·
2020
·Vol. 10
·期 10
·1102
·
IF 3.52
Fengyang Ju,Jinjin Zhang,Weiwei Lu
The electrochemical reduction of CO2is a promising way to recycle it to produce value-added chemicals and fuels. However, the requirement of high overpotential and the low solubility of CO2in water severely limit their efficient conversion. To overcome these problems, in this work, a new type of electrolyte solution constituted by ionic liquids and propylene carbonate was used as the cathodic solution, to study the conversion of CO2on an Ag electrode. The linear sweep voltammetry (LSV), Tafel characterization and electrochemical impedance spectroscopy (EIS) were used to study the catalytic effect and the mechanism of ionic liquids in electrochemical reduction of CO2. The LSV and Tafel characterization indicated that the chain length of 1-alkyl-3-methyl imidazolium cation had strong influences on the catalytic performance for CO2conversion. The EIS analysis showed that the imidazolium cation that absorbed on the Ag electrode surface could stabilize the anion radical (CO2•−), leading to the enhanced efficiency of CO2conversion. At last, the catalytic performance was also evaluated, and the results showed that Faradaic efficiency for CO as high as 98.5% and current density of 8.2 mA/cm2could be achieved at −1.9 V (vs. Fc/Fc+).Keywords:electrochemical reduction of CO2;ionic liquids;propylene carbonate;imidazolium cation
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CATALYSIS TODAY
·
2020
·
IF 5.825
Fei Yuan,Guanghui Zhang,Jie Zhu,Fanshu Ding,Anfeng Zhang,Chunshan Song,Xinwen Guo
Direct conversion of carbon dioxide (CO 2 ) into lower olefins (C 2 -C 4 = ) is highly attractive as a sustainable production route for its great significance in greenhouse gas emission control and fossil fuel substitution. Fe-based catalysts have been extensively studied in CO 2 hydrogenation, which usually show unsatisfactory selectivity toward lower olefins. Here we present a high-dispersion catalyst precursor CoFe 2 O 4 with Na (Na-CoFe 2 O 4 ) that offers C 2 -C 4 = space time yield as high as 2.88 μmol C2-C4= g cat −1 s -1 and olefin to paraffin ratio about 6 at CO 2 conversion higher than 41 %. High dispersion and the intimate contact between Fe and Co sites help inhibit the formation of methane, and favor a higher selectivity of C 2 + hydrocarbons, especially lower olefins. The presence of Na further promotes chain growth and suppresses the direct hydrogenation of Fe-(CH 2 ) n intermediates. A superior stability over 100 h was observed, demonstrating the promising potential of this catalyst for industrial applications.
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Green Energy & Environment
·
2021
·
IF 8.207
Sen Luan,Wei Li,Zanwu Guo,Wenxiu Li,Xiaojian Hou,Yi Song,Ran Wang,Qian Wang
Well-ordered hierarchically mesoporous/microporous carbon materials have been successfully fabricated by using dual soft-templating approach through compressed CO 2 . Pluronic F127 and different type of surfactants, including nonionic, cationic, and anionic surfactants, were used as dual templates to investigate the influence on the morphology and nanostructure of the as-prepared carbon samples. TEM, SEM, N 2 sorption, wide-angle and small-angle XRD analysis were employed to reveal the well-ordered hierarchically micro-mesoporous structure with 2D hexagonal symmetry by using compressed CO 2 . The prepared HPC samples with different pressures as the catalyst carriers have been functioned by chlorosulfonic acid for the fructose conversion into HMF. Chlorosulfonic acid concentration, catalyst dosage and reaction temperature have been optimized for fructose-to-HMF transformation with the obtained catalyst. The performances of as-made HPC–SO 3 H samples in HMF yield and reaction rate of fructose-to-HMF transformation have been investigated. The stability of the samples was also conducted in the dehydration of fructose to HMF for five cycles. The possible catalytic mechanism by using hierarchically porous carbon materials as catalyst support for fructose-to-HMF transformation was proposed.
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APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Huanhuan Li,Mingyang Tan,Can Huang,Weiping Luo,Shuang-Feng Yin,Weijun Yang
Functional nanosheets have attracted great attention due to their potential applications in catalysis chemistry and material science. Herein, Co 3 O 4 nanoparticles interconnecting with nitrogen-doped carbon architectures (denoted as Co 3 O 4 /NC) was developed on nickel foam surface by a two-step solvothermal process and followed by calcination. A metal organic framework (MOF) of laminar CoMOF-NH 2 was synthesized firstly by in-situ transformation of Co 2 (OH) 3 Cl array. Then, porous Co 3 O 4 /NC nanosheets were obtained by controlled heat treatment of CoMOF-NH 2 . The Co 3 O 4 /NC supported by nickel foam can be directly used as self-supported electrodes for electrocatalysis without any binders. As-synthesized Co 3 O 4 /NC acts as effective catalysis for oxygen evolution reaction (OER). Interestingly, the optimized electrochemical efficiency for OER was achieved by Co 3 O 4 /NC nanosheet with overpotentials of 235 mV and 264 mV offering current densities of 10 mA/cm 2 and 100 mA/cm 2 , respectively. It also has a relatively low Tafel slope, which indicates the fast electron transfer kinetics of the catalyst. So Co 3 O 4 /NC nanosheet has great potential in replacing precious metal electrocatalysts in OER application.
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高影响因子
Journal of Materials Chemistry A
·
2020
·Vol. 8
·期 46
·24486-24492
·
IF 11.301
Wei-Wen Yuan,Jian-Xiang Wu,Xiang-Da Zhang,Shu-Zhen Hou,Ming Xu,Zhi-Yuan Gu
The bismuth-based materials are proven as valid electrocatalysts for electrochemical conversion of carbon dioxide (CO2) into formate (HCOO−). Herein, we discover that HCO3− can destroy the Bi–O bonds of the bismuth–carboxylate MOF to achieve in situ transformation into Bi2O2CO3 (MOF-derived Bi2O2CO3), which is merely explored yet. MOF-derived Bi2O2CO3 shows superior electrocatalytic performance in a broad range of potentials and demonstrates a formate faradaic efficiency (FEHCOO−) of 96.1% as well as an outstanding durability in 48 h with a current density about 10 mA cm−2 at a potential of −0.669 V vs. RHE. And compared with the structurally similar bismuth oxyhalides, MOF-derived Bi2O2CO3 possesses higher stability and lower CO2 concentration-dependence during CO2 reduction. Furthermore, this work puts a new strategy forward to achieve in situ MOF transformation and to comprehend the stability of electrocatalysts.
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高影响因子
RSC Advances
·
2020
·Vol. 10
·期 56
·34187-34196
·
IF 3.119
Yuan Yuan,Jianwen Wei,Linlin Geng,Dejun Mei,Lei Liao
An amine-bifunctionalized composite strategy was used to fabricate grafted-impregnated micro-/mesoporous composites for carbon dioxide capture. The micro-/mesoporous Beta/KIT-6 (BK) composite containing a high-silica zeolite with a three-dimensional twelve-membered ring crossing channel system and cubic structural silica was used as a support, and 3-aminopropyltrimethoxysilane (APTS) and tetraethylenepentamine (TEPA) were used as the grafted and impregnated components, respectively. The amine efficiency, adsorption kinetics, thermal stability, regeneration performance, and the effects of impregnated amine loadings (30–60%) and temperatures (40–90 °C) on the CO2 adsorption performance were investigated using a thermal gravimetric analyzer (TGA) in the mixed gases (15 vol% CO2 and 85 vol% N2). At 60 °C, the bifunctionalized Beta/KIT-6 (1 mL APTS g−1 BK) displayed the highest CO2 adsorption capacity of 5.12 mmol g−1 at a TEPA loading of 50%. The kinetic model fitting results showed that the CO2 adsorption process was a combination of physical and chemical adsorption, wherein the chemical adsorption is dominant. After five adsorption/desorption cycle regenerations, the saturated adsorption capacity of the composite material was 4.86 mmol g−1, which was only 5.1% lower than the original adsorption capacity. The composites demonstrated excellent CO2 adsorption performance, indicating the promising future of these adsorbents for CO2 capture from actual flue gas after desulfurization.
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高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2020
·
IF 3.408
Bijiao Gu,Yaqin Zhang,Manoj Pudukudy,Yunfei Zhi,Lei He,Shuai Jin,Shaoyun Shan,Waseem Tariq
Using solid waste carbide slag (CS) as a calcium precursor and silicon nitride (Si 3 N 4 ) as a new inert dopant , a series of calcium oxide (CaO)-based adsorbents were prepared by a simple dry mixing method and high temperature CO 2 cyclic adsorption property was tested in a thermogravimetric analyzer (TGA). A lot of matters were studied in this work like the effects of Si 3 N 4 type, dopant content, pre-calcination conditions, CO 2 concentration and long-term cycles on CO 2 adsorption property. The phase composition, surface morphology and surface area of the adsorbents were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Nitrogen Physisorption analyses. The cyclic conversion experiments of three kinds of Si 3 N 4 such as α-Si 3 N 4 , β-Si 3 N 4 and the self-prepared Si 3 N 4 by sol-gel method showed that the adsorbents doped with the self-prepared Si 3 N 4 had a superior cyclic adsorption property (68.34% after 10 cycles). The calcined CS (CCS) doped with 5 wt% self-prepared Si 3 N 4 , pre-calcined at 850 °C for 4 h (CCS–Si 3 N 4 -5-4-850) exhibited a higher conversion (>70% after 10 cycles, 57.09% after 20 cycles). The incorporation of Si 3 N 4 inhibited the sintering between the adsorbent particles, which is in favor of enhancing the cyclic adsorption durability. The adsorption kinetics showed that the activation energies of CCS-Si 3 N 4 -5-4-850 chemisorption and diffusion were estimated to be 68.17 kJ/mol and 102.34 kJ/mol, respectively, which are consistent with the actual adsorption process .
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CATALYSIS LETTERS
·
2020
·Vol. 151
·期 6
·1810-1820
·
IF 2.482
Zhao Nannan,Wang Songbo,Cheng Penggao,Zhang Jianping,Zhang Lei,Du Wei,Tang Na
Co 3− x Mn x O 4 is a bimetal oxide with excellent electrochemical activity in alkaline solution, has been regarded as a promising alternative in the field of ion-air batteries and proton exchange membrane fuel cell (PEMFC). Herein, we report a simple solvothermal-calcination method to fabricate Co 3− x Mn x O 4 with tunable external Co 3+ /Co 2+ and Mn 3+ /Mn 2+ ratio. The tunable ratio of element valence in the bimetal results in a higher exposure of active center for oxygen redox reaction (ORR), and thus lead to a better ORR activity, which was confirmed by X-ray photoelectron spectroscopy characterizations and electrochemical measurements. Specially, Co 1.8 Mn 1.2 O 4 with a Co 3+ /Co 2+ ratio of 2.08 showed an overpotential of 0.37 V at benchmark ORR current density of 3 mA/cm 2 in 0.1 M KOH, which is lower than that of pure oxide (Mn 3 O 4 0.53 V and Co3O4 0.56 V). In addition, the as prepared Co 1.8 Mn 1.2 O 4 exhibited a positive half-wave potential (0.83 V vs RHE) due to their more active sites, promotes charge transfer, adsorption and desorption of oxygen species. This work provides a strategy for the design and fabrication of earth-abundant, low-cost electrocatalysts for PEMFC in practical applications. Graphic Abstract Co 3− x Mn x O 4 was fabricated by tuning external Co 3+ /Co 2+ and Mn 3+ /Mn 2+ ratio, and the activity initially shows a positive correlation with the ration of Co 3+ /Co 2+ in Co 3− x Mn x O 4 .
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CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Huiyuan Cheng,Xuemei Wu,Xiangcun Li,Xiaowa Nie,Shuai Fan,Manman Feng,Zihao Fan,Mingqian Tan,Yonggang Chen,Gaohong He
Although considerable progress has been achieved by Cu nanoparticles for catalyzing CO 2 reduction reaction (CO2RR), Cu single atom catalysts (Cu SACs) are generally suffered from inferior performance to that of widely investigated Fe, Co, Ni SACs. This phenomenon mainly ascribes to the lack of effective geometry and electronic engineering of copper active center from an atomic level. Herein, highly exposed atomically dispersed Cu-N x ( x denotes Cu–N coordination number) sites anchored on 3D porous carbon matrix are successfully synthesized through facile one step thermal activation, and Cu-N 4 sites exhibit boosted activity and selectivity compared to its nearly inert Cu-N 3 counterparts. Aided by density functional theory (DFT) calculations, the edge-hosted Cu-N 4 moieties are revealed as key active sites for efficient CO generation via optimized local coordination environment and electronic properties, which strongly interact with *COOH intermediate and facilitate the desorption of *CO. As a result, Cu-N 4 catalyst achieves high CO Faradaic efficiency (FE CO ) of over 90% from −0.6 to −1.1 V vs . RHE with a maximum value of 98%, surpassing the previously reported Cu SACs for CO 2 -to-CO conversion. This work provides new insight into proper Cu SACs design and fundamental mechanism understanding to boost CO2RR.
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高影响因子
ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Zhibiao Chen,Guohua Jing,Bihong Lv,Zuoming Zhou
A nonaqueous, phase-change absorbent of 2-amino-2-methyl-1-propanol (AMP)/piperazine (PZ) and environmentally friendly solvent dipropylene glycol dimethyl ether (DME) fixes a number of issues suffered by a solid–liquid biphasic solvent, such as high viscosity of the saturated solution and difficult separation and regeneration of the viscous solid. The solid phase occupies 43% of the total volume while attributes about 94% of the total loading (0.87 mol mol–1) of the solution. Beside the formation of AMP-carbamate and PZ-carbamate according to zwitterions mechanism, the coupling products of AMP/PZ-carbamate are also found in the crystal, which helps to reduce the desorption temperature during the regeneration. Because of low solubility, self-aggregation, and high lattice energy in DME, the CO2 products precipitate and form a white crystalline powder in the lower phase of the solution. Meanwhile, the solid precipitation helps the bulk solution to keep a lower partial pressure and higher diffusivity of CO2, conforming a perfect performance of CO2 capture into the biphasic solvent. The regeneration heat duty of the solvent (1.61 GJ t–1 CO2) was approximately 57% less than that of the benchmark monoethanolamine (MEA) because of its perfect performance on CO2 capture, such as high absorption loading, high regeneration efficiency, and low amount of rich phase required for regeneration. The novel absorbent has a great potential for green and sustainable CO2 capture.
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高影响因子
危险品化学品经营许可证（带存储）