APPLIED CATALYSIS B-ENVIRONMENTAL
·
2022
·
IF 24.319
Wenhui Li,Xiaowa Nie,Hong Yang,Xiang Wang,Felipe Polo-Garzon,Zili Wu,Jie Zhu,Jianyang Wang,Yi Liu,Chuan Shi,Chunshan Song,Xinwen Guo
Efficient conversion of CO 2 is of great significance for sustainable supply of chemicals and fuels. While Co-based catalysts are known to be effective for CO hydrogenation in Fischer-Tropsch synthesis, they work very differently in CO 2 hydrogenation. This study reveals a crystallographic dependence of reaction pathways for CO 2 hydrogenation on Co catalyst showing a new type of structure sensitivity and structure-activity-selectivity relationship for CO 2 conversion to chemicals and fuels. The experimental work on CO 2 conversion including steady-state isotopic transient kinetic analysis (SSITKA) using 13 C-labeled CO 2 shows a preferential CH 4 formation over HCP-Co but dominant CO formation over FCC-Co. The density functional theory calculations indicate that CO 2 does dissociate directly into chemisorbed CO* and O* on both HCP-Co and FCC-Co, but the CO* intermediates on HCP-Co prefer to be hydrogenated to form CH 4 whereas the CO* on FCC-Co preferentially desorb to form CO. The significantly altered adsorption strength of CO* due to the presence of chemisorbed O* and CO 2 * species on the catalyst surface is responsible for the mechanistic disconnection in product selectivity between the CO 2 and CO hydrogenation over Co catalysts. This study also shows that the addition of K to Co diminishes the direct impact of Co crystal structure, but improves the selectivity to C 2 + hydrocarbons along with higher CO 2 conversion. This seems to result from another pathway originating from HCOO* intermediate from bonding interaction of surface Co atoms with carbon in CO 2 , leading to the formation of CH x * whose coupling subsequently give rises to C 2 + products. The present study sheds new light into the crystallographic structural sensitivity of CO 2 hydrogenation towards the rational design of more selective catalysts for CO 2 conversion.
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Materials Advances
·
2022
·Vol. 3
·期 12
·4964-4972
·
IF 0
Chong Wang,Chengdeng Wang,Zhihao Xiong,Jiashuai Wang,Wenyuan Zhang,Haofeng Shi,Donghua Wang,Yousong Gu,Zhiming Bai,Yan Gao,Xiaoqin Yan
Electrochemical CO2 reduction reactions (CO2RRs) have been recognized as a promising solution to environmental and energy problems due to their ability to convert intermittent renewable electricity into hydrocarbon fuels and value-added chemicals. Copper has a unique ability to electrochemically reduce CO2 to produce C2+ hydrocarbon products compared to other metals. However, it is still suffering from low Faraday efficiency (FE) limitations for specific products. Herein, we have prepared an Ag-modified Cu/CuO–Ag catalyst with a porous structure via a galvanic replacement reaction method, which reduced CO2 to C2+ products with the FE of 52.5% at −1.1 V (vs. RHE). The experimental results and density functional theory (DFT) calculations show that the addition of Ag in Cu is beneficial to increasing the coverage of *CO on the Cu surface, which can decrease the potential barrier energy of the C–C coupling reaction and favor the generation of C2+ products. The results of this study may be helpful to the design of efficient tandem catalysts for electrochemical CO2 reduction.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2022
·
IF 24.319
Honglin Li,Shoufu Cao,Hongman Sun,Yonglian Lu,Ying Zhang,Xiaoqing Lu,Jingbin Zeng,Zifeng Yan
Copper (Cu) has been proved as an efficient catalyst in carbon dioxide electrochemical reduction reaction (CO 2 RR) towards hydrocarbons, but still suffers from low selectivity and poor stability. Herein, Cu-based/CxNy catalysts were fabricated by facile pyrolysis of CuNCN in sealed quartz tubes. It is found that CuNCN pyrolyzed at 300 °C (CuNCN-300) exhibits a high C 2 H 4 Faradaic efficiency of 48.5% at 500 mA cm - 2 . However, increasing the pyrolysis temperature above 400 °C gives rise to CH 4 being the predominant product and CuNCN-500 achieves CH 4 Faradaic efficiencies of 66.3% at 300 mA cm - 2 . Combining experimental and DFT calculation results, Cu 3 N plays a crucial role in the formation of C 2 H 4 , while tri-s-triazine units in CuNCN-500 reduce the barrier of *CO hydrogenation to *CHO and retard C-C coupling on Cu surface. These findings mark the significance of precise tailoring of the synergistic effect between g-C 3 N 4 and different Cu species for achieving the desired selectivity during CO 2 RR.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2022
·
IF 6.437
Zijun Yi,Chao Li,Lijun Zhang,Shu Zhang,Wenran Gao,Shuang Wang,Bin Li,Xun Hu
CO 2 can be used to activate biomass for production of activated carbon at high temperatures (usually above 700 °C). At typical pyrolysis temperatures, CO 2 might also involve in biomass pyrolysis , which was investigated via pyrolysis of lignin at temperatures from 400 to 700 °C in N 2 and CO 2 atomsphere, respectively. The results suggested that CO 2 interfered with the pyrolysis process, facilitating formation of bio-oil and biochar but not gases via suppressing further gasification of volatiles. This reserved more mono-ring phenolics in bio-oil and also formed more heavier phenolics through secondary condensation routes. As for biochar, CO 2 enhanced the aromatization process, generating the carbon-rich biochar of higher heating value . The in-situ characterization of the functionalities of biochar during pyrolysis suggested that CO 2 accelerated removal of the aliphatics like -OH, -C-H, C O, and C-O-C. This rendered the biochar of hydrophobic surface but less fragmentized structures than that obtained in N 2 .
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CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2022
·Vol. 39
·期 2
·246-252
·
IF 2.726
Wang Renquan,Li Tiantian,Gao Rui,Qin Jiaqi,Li Mengyao,Guo Yizheng,Song Yujiang
With the excessive consumption of fossil fuels and the massive emission of CO 2 , it has led to a series of environmental crises posing a serious threat to sustainable development. Electrochemical CO 2 reduction reaction (CO 2 RR) to ethylene helps solve these serious environmental crises. Herein, we report the synthesis of a copper-based electrocatalyst by pyrolysis of yolk-shell structured HKUST-1 with partial substitution of trimesic acid by benzimidazole(nitrogen source). The electrocatalyst exhibits an ethylene Faradic efficiency(FE) of 25.8% and a partial ethylene current density of 23.7 mA/cm 2 , in addition, the electrocatalyst can maintain stable performance during 10 h of electrolysis, which are all better than those of the electrocatalyst without nitrogen dopant. According to electrochemical measurements and X-ray photoelectron spectroscopy(XPS), we propose that the nitrogen dopant plays an effective role in stabilizing Cu(I) species and promoting CO 2 molecules activation, as well as suppressing the reduction of Cu(I) species during electrolysis. Eventually, the performance of the electrocatalyst toward CO 2 RR is studied in a flow cell. This work provides a new route for the design of Cu-based electrocatalyst toward electrochemical CO 2 conversion into ethylene.
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CHEMISTRY-A EUROPEAN JOURNAL
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2022
·Vol. 28
·期 55
·e202201430
·
IF 5.02
Yuanyuan Zhang,Jian Liu
Graphical An artificial photosystem was constructed through the covalent attachment of Rh complex onto PCN. The integrated photocatalyst could regenerate NADH efficiently by integrating the light harvesting unit and the electron transfer unit through conjugated connection. By further coupling with FDH immobilized on the hydrophobic membrane, an enhanced HCOOH production could be obtained. Natural photosynthesis is a highly unified biocatalytic system, which coupled cofactor (NAD(P)H) regeneration and enzymatic CO 2 reduction efficiently for solar energy conversion. Mimicking nature, a novel system with Rh complex covalently grafted onto NH 2 -functionalized polymeric carbon nitride (NH 2 -PCN) was constructed. The integrated connection of the light-harvesting and electron mediation modules as Rh m3 -N-PCN could promote the efficient NAD + reduction to NADH. As a result, the integrated system exhibited a conversion of ∼66 % within 20 minutes. By further coupling in situ generated NADH with formate dehydrogenase (FDH), a photoenzymatic production of formic acid (HCOOH) from CO 2 was accomplished. Moreover, by immobilizing FDH onto a hydrophobic membrane, an enhanced HCOOH production of ∼5.0 mM can be obtained due to the concentrated CO 2 on the gas-liquid-solid three-phase interface. Our work herein provides an integrated strategy for coupling the anchored electron mediator with immobilized enzyme for enhanced artificial photosynthesis.
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PubMed
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CHINESE JOURNAL OF POLYMER SCIENCE
·
2022
·Vol. 40
·期 10
·1183-1192
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IF 3.815
Zhang Hong-Ming,Han Guang-Ping,Cheng Wan-Li,Liu Shun-Jie,Wang Xian-Hong
High solid content CO 2 -based cationic waterborne polyurethanes (CWPUs) were prepared using CO 2 -polyols as soft segment and N -methyl diethanolamine (MDEA) as hydrophilic group. The resulting stable aqueous dispersion displayed a high solid content of 52% with a low MDEA loading of 3.52 wt%. This novel structural CWPU can provide excellent adhesive strength, whose T-peel strength could reach 173.48 N/5cm, 20% higher than that of ester-based cationic waterborne polyurethane (87.55 N/5cm). The CO 2 -based CWPU film showed only 2 wt% swelling percentage after 240 min immersion in water, and no change was observed during its immersion in 5 wt% sodium hydroxide solution. The tensile strength of CO 2 -WPUs dropped slowly to 91.2% after 480 min immersion in a 5 wt% sodium hydroxide solution, whereas that of ester-based CWPUs dropped quickly to 32% after 240 min and their mechanical properties were lost after 360 min immersion. Meanwhile, the retention of the tensile strength of the CO 2 -CWPUs was 81.5% even after 720 min immersion in 10 wt% H 2 O 2 solution, while it was only ca . 38% for the ester-based CWPUs. These results indicated that the cationic CO 2 -based CWPU may be promising waterborne adhesive with outstanding ageing resistance due to its synergistic effect from carbonate and ether groups of CO 2 -polyol structure.
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Nature Catalysis
·
2022
·Vol. 5
·期 6
·564-570
·
IF 40.706
Xie Yi,Ou Pengfei,Wang Xue,Xu Zhanyou,Li Yuguang C.,Wang Ziyun,Huang Jianan Erick,Wicks Joshua,McCallum Christopher,Wang Ning,Wang Yuhang,Chen Tianxiang,Lo Benedict T. W.,Sinton David,Yu Jimmy C.,Wang Ying,Sargent Edward H.
Renewable electricity-powered CO 2 reduction to multi-carbon (C 2+ ) products offers a promising route to realization of low-carbon-footprint fuels and chemicals. However, a major fraction of input CO 2 (>85%) is consumed by the electrolyte through reactions with hydroxide to form carbonate/bicarbonate in both alkaline and neutral reactors. Acidic conditions offer a solution to overcoming this limitation, but also promote the hydrogen evolution reaction. Here we report a design strategy that suppresses hydrogen evolution reaction activity by maximizing the co-adsorption of CO and CO 2 on Cu-based catalysts to weaken H* binding. Using density functional theory studies, we found Pd–Cu promising for selective C 2+ production over C 1 , with the lowest ∆ G OCCOH* and ∆ G OCCOH* - ∆ G CHO* . We synthesized Pd–Cu catalysts and report a crossover-free system (liquid product crossover <0.05%) with a Faradaic efficiency of 89 ± 4% for CO 2 to C 2+ at 500 mA cm −2 , simultaneous with single-pass CO 2 utilization of 60 ± 2% to C 2+ .
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ChemNanoMat
·
2022
·Vol. 8
·期 10
·e202200269
·
IF 3.82
Ziye Guo,Huanhuan Yang,Qingyong Tian,Wenjie Ma,Qun Xu,Buxing Han
Graphical A template- and surfactant-free top-down strategy was developed to transform non-vdW bulk CeO 2 into 2D amorphous CeO 2− x nanosheets with defective structure for the first time by cleaving Ce−O covalent bonds with the assistance of supercritical CO 2 . The unique nanosheets show outstanding UV-vis adsorption and photoluminescence properties due to the disordered atomic structure and increased vacancy defects (F-centers). Two-dimensional (2D) non-van der Waals (non-vdW) amorphous nanomaterials have attracted much attention for optical, catalytic and biomedical applications owing to their rich dangling bonds and unsaturated coordination. CeO 2 , a typical non-vdW material, with amorphous 2D structure and intrinsic optical properties have rarely been prepared via a top-down method due to the lack of anisotropy in its 3D bonding network. Herein, we develop an environmentally-friendly top-down method to achieve ultrathin 2D amorphous CeO 2− x with controllable defects from bulk CeO 2 by utilizing supercritical CO 2 . The unique CeO 2− x nanosheets exhibit outstanding ultraviolet-visible adsorption and photoluminescence (PL) properties due to the disordered atomic structure and increased vacancy defects resulting from the cleavage of Ce−O covalent bonds and amorphization of CeO 2 . In addition, the defect-related emission mechanism of the visible PL for the as-prepared 2D CeO 2− x nanosheets has been proposed.
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Journal of Cleaner Production
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2022
·
IF 11.072
Ma Wenjing,Dai Shanshan,Li Xiaojiang,Hongsheng Lu
Oily wastes are easily generated in many processes of exploitation, solvent extraction is the common method for treating the oily waste. However, traditional solvent extractions are difficult to recycle the solvent, and oil is difficult to separated. As a low-volatility solvent, ionic liquid is simple in synthesis, low in cost, so it has good application prospect. In this work, the sustainable separation of oil from oily waste was implemented by using CO 2 -switchable ionic liquids. On the basis of solvent extraction, ionic liquids can reduced losses and costs. The CO 2 -switchable ionic liquids were prepared by poly (propylene glycol) bis(2-aminopropyl ether) D-230 and fatty acids with low volatility at the mole ratio of 1:2. Upon the alternate bubbling CO 2 and N 2, ionic liquids could be transformed alternately from water-miscible state to water-immiscible state. The water-immiscible state was bi-phasic system containing hydrophobic fatty acids and ammonium bicarbonate solution by bubbling CO 2 . Based on the bi-phasic system, the oil (kerosene, paraffin oil and crude oil) could be mixed with fatty acids, and were separated from fatty acids in the hydrophilic state upon N 2 , where the recovery rate of oil was more than 97% and fatty acids was not residual in recovered oil. Treating oily waste, the oil could be extracted from oily waste by the bi-phasic system. The ionic liquids were reused and the oil was separated by bubbling N 2 without extra additives, where the recovery rate of oil from oily waste was more than 85.57%. Due to the simplified process and negligible solvent loss, the economic benefit of recovering per barrel crude oil reached 76.7% of the price of crude oil. Compared with the existing technology , this sustainable separation is simpler, more economical and more environmentally friendly. Hence, it is expected that this sustainable separation based on CO 2 -switchable ionic liquids will meet the development of green separation with low-energy consumption.
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Journal of CO2 Utilization
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2022
·
IF 8.321
Yuanping Zhang,Hongguang Liang,Xiaoyun Li,Qifeng Li,Junwei Wang
A highly efficient melem based mesoporous metal-free catalyst with amino and hydroxyl groups was successfully developed by template method with melamine as precursor and nano-SiO 2 as template. In the absence of any co-catalyst and solvent, the catalyst mp-CN-450 exhibits high catalytic activity for catalytic cycloaddition reaction between CO 2 and polyfunctional epoxides , and the epoxides conversion and corresponding cyclic carbonates selectivity are 99.7 % and 99.5 %, respectively. And the catalyst has hardly loss of catalytic activity after being reused for four cycles. The characterization results disclose that the high catalytic activity of the catalyst is closely related to its large specific surface area, abundant mesoporous structure and synergistic effect of N species and hydroxyl groups of melem hydrates. Additionally, through the study of different N-containing compounds, it was found that the primary amine may underwent a ring-opening reaction with epoxide. But with the addition of CO 2 , amine groups prior to reacted with CO 2 to form carbamate salt , avoided the formation of by-products, thereby improved the selectivity of cyclic carbonate. Finally, based on the above research, a possible reaction mechanism for the coupling of CO 2 to epoxides was proposed.
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Small
·
2022
·Vol. 19
·期 13
·2201305
·
IF 15.153
Boyu Yang,Shubin Li,Wei Mu,Zhao Wang,Xiaojun Han
The bottom-up constructed artificial cells help to understand the cell working mechanism and provide the evolution clues for organisms. The energy supply and metabolism mimicry are the key issues in the field of artificial cells. Herein, an artificial cell containing cyanobacteria capable of light harvesting and carbon dioxide fixation is demonstrated to produce glucose molecules by converting light energy into chemical energy. Two downstream “metabolic” pathways starting from glucose molecules are investigated. One involves enzyme cascade reaction to produce H 2 O 2 (assisted by glucose oxidase) first, followed by converting Amplex red to resorufin (assisted by horseradish peroxidase). The other pathway is more biologically relevant. Glucose molecules are dehydrogenated to transfer hydrogens to nicotinamide adenine dinucleotide (NAD + ) for the production of nicotinamide adenine dinucleotide hydride (NADH) molecules in the presence of glucose dehydrogenase. Further, NADH molecules are oxidized into NAD + by pyruvate catalyzed by lactate dehydrogenase, meanwhile, lactate is obtained. Therefore, the cascade cycling of NADH/NAD + is built. The artificial cells built here pave the way for investigating more complicated energy-supplied metabolism inside artificial cells.
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