Chemical Science
·
2024
·
IF 7.6
Yonghui Zhang,Xin Xu,Qingxuan Geng,Qingwei Li,Xiuli Li,Yixuan Wang,Zihuan Tang,Biao Gao,Xuming Zhang,Paul K. Chu,Kaifu Huo
Alkali activation was the common method to prepare commercial porous carbon. In a mixed alkali activation system, the role of individual alkali was generally assumed to be the same as in single alkali activation system, and only low corrosiveness of weak alkali was mostly emphasized. However, the intrinsic roles of individual alkali should be finely understanded and redefined to illuminate the activation pathway from the perspective of internal chemical reactions rather than corrosiveness. Herein, combing the in situ TG-MS analysis, DFT calculation and other characterizations, the activation processes were precisely tracked and the activation pathways were proposed. In the mixed alkali activation system, the strong alkali KOH served as the activation promoter, first decomposing into K2O, which then attacks the C-C bonds, forming active reaction sites defined as pore seeds. The weak alkali K2CO3 acted as the activation pathway modifier, CO32− preferentially etched the pore seeds over K2O due to the lower reaction barrier of CO32− interacting with the pore seeds. Consequently, the rough etching reaction of KOH was replaced and suppressed by the gentler action of CO32− forming more micropores. When the ratio of strong to weak alkali was 1:1, the obtained CK1K2-122 owned the highest microporosity (82.61%) and large specific surface area (1962.18 m2 g-1). It exhibited high specific capacitance of 296.7 F g-1 and excellent cycling stability with 98.3% retention after 10,000 cycles. The supercapacitor demonstrated high energy density of 114.4 Wh kg-1 at power density of 17.5 kW kg-1, with a broad potential window of 3.5 V.
研究领域:
材料科学
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化学工程
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DOI
PubMed
高影响因子
APPLIED CLAY SCIENCE
·
2014
·
IF 2.703
Lu Zeng,Dan-yang Cao,Yan Xu,Chun-wei Fan,Xiao-qin Peng
This paper introduces a novel method for the preparation of a geopolymer using kaolinite intercalation compound which is calcined at a low temperature and forms a geopolymer by alkaline activation . The samples were characterized by X-ray diffraction (XRD), Thermogravimetric/Differential scanning calorimetry (TG/DSC) and Fourier transformed infrared spectroscopy (FTIR). Coal-bearing strata kaolin (CSK) mainly consisting of kaolinite and quartz was used to prepare the intercalation compound (CSK-K) with potassium acetate (KAc) and calcined below 400 °C. The calcination temperature and the dosage of KAc were analyzed. The results showed that CSK calcined below 400 °C cannot be alkali-activated to harden and when the dosage of KAc was 30% by mass of CSK, CSK-K calcined between 350 °C and 400 °C can be alkali-activated to form the geopolymer with a high compressive strength around 31 MPa. This was attributed to the formation of metakaolin and geopolymerization which were related to the effect of intercalation reaction and the content of K + . CSK-K calcined at low temperature has great potential as a novel material for the manufacture of geopolymers.
研究领域:
材料科学
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地质学
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DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2018
·Vol. 26
·期 2
·1445-1454
·
IF 2.8
Wang Daiyao,Zou Jing,Cai Huahua,Huang Yixin,Li Fei,Cheng Qingfeng
Advanced oxidation processes offer effective solutions in treating wastewater from various industries. The process of alkali-activated hydrogen peroxide (H 2 O 2 ) was superior for the treatment of alkaline dye wastewater because no additional reagents were required except H 2 O 2 . However, an important and interesting phenomenon had been observed that the primary reactive species were found different for degrading organic pollutants with the process of alkali-activated H 2 O 2 . Azo dye of Orange G (OG) and triphenylmethane dye of Rhodamine B (RhB) were chosen as the target organic pollutants. The influences of various parameters on OG and RhB degradation by alkali-activated H 2 O 2 were evaluated. Furthermore, different scavengers, including ascorbic acid, methanol, t -butanol, isopropyl alcohol, furfuryl alcohol, and nitro blue tetrazolium, have been tested to identify the active species involved in dye degradation, and it was found that O 2 ·− was mainly responsible for degrading OG, while HO 2 − anion was the primary oxidant for degrading RhB.
研究领域:
环境科学
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化学工程
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DOI
PubMed
高影响因子
Environmental Technology & Innovation
·
2021
·
IF 5.263
Yuhan Xia,Yiping Jin,Jiaxu Qi,Huan Chen,Guang Chen,Shanshan Tang
Fomes fomentarius (L.) J. J. Kickx (FF), a fungal hyphae causing tree decay, has confused people for many years on how to deal with it economically and efficiently. In this study, fungal hyphae from FF was first time used as the carbon source to prepare biomass carbon material (BCFF) material via a simple method including carbonization at 600 °C and sodium hydroxide activation. Notably, BCFF-Na4-700-60 (with alkali-carbon ratio of 4:1 and heated at 700 °C for 60 min) showed a large specific surface area (3352 m 2 g −1 ) and a high pore volume (2.29 cm 3 g −1 ). Moreover, the synthetic dye brilliant green (BG) was selected as the dye model to investigate the adsorption performance and mechanism. The maximum adsorption capacity of BCFF-Na4-700-60 was 3166 mg g −1 at pH value of 9, which is superior to those of the great majority of adsorbents. After ten cycles, the adsorption capacity could still be maintained at about 53% of the original value. The results of these studies indicate that biomass carbon materials modified with forest pathogen have excellent adsorption capacity and cycling stability, which could be considered as a potential adsorbent for treatment of wastewater from dyeing industry. More importantly, this rapid and effective method can be further applied to other similar fungal hyphae.
研究领域:
环境科学
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材料科学
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生物学
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DOI
高影响因子
ACS Omega
·
2022
·
IF 4.132
Xia Wang,Wulan Zeng,Xiangjun Kong,Chunling Xin,Yani Dong,Xiude Hu,Qingjie Guo
To achieve the “double carbon” (carbon peak and carbon neutrality) target, low-cost CO2 capture at large CO2 emission points is of great importance, during which the development of low-cost CO2 sorbents will play a key role. Here, we chose peanut shells (P) from crop waste as the raw material and KOH and K2CO3 as activators to prepare porous carbons by a simple one-step activation method. Interestingly, the porous carbon showed a good adsorption capacity of 2.41 mmol/g for 15% CO2 when the mass ratio of K2CO3 to P and the activation time were only 0.5 and 0.5 h, respectively, and the adsorption capacity remained at 98.76% after 10 adsorption–desorption cycle regenerations. The characterization results suggested that the activated peanut shell-based porous carbons were mainly microporous and partly mesoporous, and hydroxyl (O–H), ether (C–O), and pyrrolic nitrogen (N-5) functional groups that promoted CO2 adsorption were formed during activation. In conclusion, KOH- and K2CO3-activated P, especially K2CO3-activated P, showed good CO2 adsorption and regeneration performance. In addition, not only the use of a small amount of the activator but also the raw material of crop waste reduces the sorbent preparation costs and CO2 capture costs.
研究领域:
材料科学
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环境科学
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DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2023
·Vol. 24
·期 18
·14313
·
IF 5.6
Jiaqi Shi,Lei Wang,Shang Gao,Jianbo Huang,Hao Yang,Hao Lu,Shaohua Cao
Alkali-activated persulfate (PS) is widely used in situ in chemical oxidation processes; however, studies on the innovation of the alkali activation process are very limited. Two supported solid superbases, namely KNO3/γ-Al2O3(KAl) and KNO3/SBA-15/MgO (KSM), respectively, were prepared and used to activate persulfate to degrade DCF in this work. The results showed that the superbases elevated the solution pH once added and thus could catalyze persulfate to degrade diclofenac efficiently above pH 10.5. The catalytic efficiency of KAl was close to that of sodium hydroxide, and that of KSM was the highest. The mechanism might be that, in addition to raising the solution pH, some potassium existed as K2O2, which had a strong oxidizing effect and was conducive to DCF removal. Hydroxyl, sulfate and superoxide radicals were all found in the reaction system, among which hydroxyl might play the most important role. The material composition ratio, common anion and humic acid all had some influences on the catalytic efficiency. A total of five intermediates were found in the KSM/PS oxidation system, and six oxidation pathways, which were hydroxylation, dehydrogen, dechlorination, dehydration, decarboxylation, and C-N bond breakage, might be involved in the reaction process. Several highly toxic oxidation products that should be paid attention to were also proposed.Keywords:base-activated persulfate;catalytic mechanism;diclofenac;solid superbase
研究领域:
环境科学
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化学工程
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DOI
PubMed
高影响因子
IONICS
·
2024
·
IF 2.4
Yang Nana,Xiong Shanxin,Zhang Shuai,Lv Fengyan,Zhang Yukun,Wang Xiaoqin,Chu Jia,Li Zhen,Xu Jianwei
Coal gasification fine slag (CGFS) is a by-product of coal and gasification agent interactions at high temperatures, which presents significant challenges for the coal chemical industry. CGFS mainly comprises SiO 2 , Al 2 O 3 , CaO, Fe 2 O 3 , and carbon. Carbon-rich particles (CRP) in the CGFS contain large amounts of residual carbon and small amounts of metal compounds. Among them, the acid leaching of metal ions can produce the mesoporous structure in CRP. The mesoporous structures not only provide channels for the embedding of potassium vapor and the overflow of CO 2 and other gases during KOH activation, but also provide channels for the transport of electrolyte ions. Therefore, studying the acid leaching process and elemental leaching of CRP is highly significant. In this paper, the dissolution kinetics and mechanism of elements in CRP during acid leaching were studied and the acid leaching conditions were optimized using CRP as raw materials. Results from BET and chemical tests indicated that the mesoporous structure formation via acid leaching was a first-order kinetic reaction under the optimum conditions. Subsequently, the process parameters of alkali deashing and KOH activation were optimized. The prepared activated carbon CRP-AC-90 has a surface area of 1409.93 m 2 /g, high-specific capacitance and excellent cycle stability, which shows the application potential of CRP in supercapacitors and provides a new method for effective utilization of CRP.
研究领域:
能源材料
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环境工程
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化学工程
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DOI
高影响因子
Carbon Letters
·
2020
·Vol. 31
·期 1
·29-37
·
IF 1.992
Wang Qi,Lv Yaying,Zhu Tao
Biomass porous carbons derived from Laminaria japonica were prepared by KOH and H 3 PO 4 activation methods, respectively. The results indicated that the chemical activation had an apparent effect on the molecular framework and space of materials. To enhance the selective adsorption for organic acids, biomass carbons were modified by dopamine combined with N -(2-aminoethyl)-3-aminopropyltrimethoxysilane. The SEM and BET results illustrated the effect of the chemical activation approach on the morphology and porous texture. The biomass porous carbon using KOH activation method had the highest surface area (up to 1558 m 2 /g). Compared with unmodified materials, the modified materials showed higher adsorption capacity for organic acids (27.90 μg/mL for chlorogenic acid and 25.47 μg/mL for caffeic acid). It was suggested that modification of porous carbons might be a viable pathway to increase the specific adsorption affinity and efficiency for organic acids in dried jujube samples.
研究领域:
材料科学
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环境科学
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化学工程
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DOI
高影响因子
ACS Applied Materials & Interfaces
·
2020
·
IF 8.758
Xin Cui,Yu Cui,Meiling Chen,Rui Xiong,Yucheng Huang,Xiaowang Liu
We present that activation of CoMoO4-based microrod arrays in KOH (1.0 M, 2 h) allows us to significantly improve their electrochemical hydrogen evolution performance in phosphate buffer solution (1.0 M, pH = 7.1). The activation mechanism originates from the conversion of the surface layer of CoMoO4 to Co(OH)2 nanosheets, together with the release of Mo3O102– ions into the activation solution. Our experimental and calculated results suggest that the Co(OH)2 nanosheets on the surface of the CoMoO4-based microrod arrays show the ability to improve water molecule disassociation and stabilize the catalytic activity of the two-component catalysts by decreasing their overpotentials in the hydrogen evolution reaction. When extending this strategy to activate P-doped CoMoO4 with a low hydrogen absorption free energy, we report the synthesis of a new class of superior neutral electrochemical hydrogen evolution catalysts of P-doped CoMoO4–Co(OH)2 microrod arrays. We show that a low overpotential of about 30 mV (obtained from bulk electrolysis) is required to deliver a current density of 10 mA cm–2 in the neutral media. By making use of our catalyst and NiFe double hydroxide as cathodic and anodic electrodes, respectively, we fabricated a two-electrode electrolysis device for neutral overall water splitting. Our results showed a low cell voltage of 1.78 V (obtained from bulk electrolysis) that is needed for delivering a current density of about 10 mA cm–2 in the neutral electrolyte, even outperforming the state-of-the-art catalyst combination of Pt/C∥RuO2 in terms of catalytic activity and stability. These findings suggest that our strategy may be utilized as a facile but useful strategy toward the activation of molybdate catalysts to improve their HER performance in both basic and neutral media.
研究领域:
材料科学
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电化学
·
可再生能源
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DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Zhenya Zhang,Min Zhang,Bowen Xing,Ting Liu
Conventional coal-based carbon activation usually requires strong acid washing operation after activation, which not only consumes more experimental time but also pollutes the environment. In this study, a novel method for the preparation of coal-based carbon gas-sensitive materials is described and its gas-sensitive properties are investigated. Specifically, a novel composite coal-based carbon/K 2 CO 3 gas-sensitive material was prepared more easily by using low-cost coal as the carbon source and KOH as the activator without acid washing after activation, which was unexpectedly found to possess excellent gas-sensitive properties, which gave us great encouragement. The samples obtained at the activation temperature of 500 °C and with a carbon-to-alkali ratio of 1:1 have more defective active sites as well as chemisorbed oxygen content, which is advantageous for enhancing the gas-sensitive performance of the samples. In addition, the introduced alkaline potassium carbonate component also favors the adsorption of acidic formaldehyde gas. The response of the sensor fabricated using the above sample was 6415.68 % for 500 ppm formaldehyde at room temperature and a response cycle was completed in about ten seconds. In addition, the fabricated gas sensor was applied to the monitoring of volatile formaldehyde in paints, which shows that the sensor has the potential to be applied in the detection of formaldehyde gas emitted in the field of home decoration and building materials.
研究领域:
材料科学
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环境监测
·
传感器技术
·
化学检测
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产品关联
DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2025
·
IF 3.7
Weijun Ma,Zejia Zhu,Xuxin Qiu,Yaocheng Yan,Dongdong Zhang,Yongdong Jiang
Graphical Ultra-high specific surface area porous carbon: hierarchical porous carbon material (HPC-300) was prepared by using polyacrylonitrile as carbon source and potassium hydroxide as activator. The symmetric supercapacitor assembled using HPC-300 has an energy density of 11.7 Wh kg −1 at a specific power of 250 W kg −1 . The porous structural tailoring of polyacrylonitrile-based carbon materials is the key to maximize capacitive performance. Herein, hierarchical porous carbons (HPC) with high specific surface area and controllable porosity are synthesized by preoxidation assisted alkali activation strategy using polyacrylonitrile as the precursor. The results show that high preoxidation temperature is beneficial to increase the specific surface area and pore volume of HPC. The optimized HPC-300 has a high BET specific surface area of 3161 m 2 g −1 , a micropore volume of 1.45 cm 3 g −1 , and an A D /A G of 3.56. Electrochemical test shows that the specific capacitances of HPC-300 in 6 M KOH electrolyte at 1 A g −1 and 10 A g −1 are 314.1 F g −1 and 213.0 F g −1 , respectively, with a capacitance retention of 67.8 %. The assembled supercapacitors based on HPC-300 deliver an energy density of 11.7 Wh kg −1 at a power density of 250.0 W kg −1 in KOH electrolyte and 21.1 Wh kg −1 at 450.0 W kg −1 in Na 2 SO 4 electrolyte and possess a capacitance retention of 98.1 % over 20,000 charge-discharge cycles. This preoxidation coupled activation method provides a potential strategy for the preparation of PAN-based porous carbon with high specific surface area and capacitance.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Yuzhen Zhang,Jun Dai,Juan Yang,Jianping Wei,Dongtao Wu,Chongchong Leng
The effects of alkali-activated potassium persulfate solution (AAP) immersion on coal surface wettability and pore structure were systematically investigated in this study. Experimental results indicated when mass fraction of potassium persulfate and sodium hydroxide was 1.5 % and 0.5 %, activation temperature was 30 °C, anthracite wettability was improved most significantly. Under the optimal conditions, capillary reverse osmosis height of the AAP-treated coal samples reached 8.1 cm, and water-droplet contact angle θ decreased markedly from 112.97° to 55.08°. Relative content of oxygen-containing groups –C O and OH–OH increased most significantly. Coal molecular structure models were constructed and theoretical simulation results showed that both H 2 O adsorption capacity and adsorption heat increased after AAP immersion, and the AAP-treated coal samples can absorb a large number of water molecules even at lower pressure. Spray dust-suppressing efficiency increased from 33.42 % to 74.65 % by using AAP. The radicals (SO 4 · − and · OH) in AAP could in-situ oxidize and corrode active organic molecules in coal matrix, expanding original pores and creating new pores-fractures on coal surface. Average pore diameter increased by 17.40 %, while specific surface area decreased by 51.14 %, and internal pore surface became smoother. Additionally, methane adsorption constant a and b value of the AAP-immersed coal samples decreased by 6.42 % and 32.68 %. Compared with previous reports on wettability regulation, this study not only enhanced the wettability of coal samples, but also improved their pore structure. These findings provide crucial technical support for innovative development of dust suppression and outburst prevention technologies in coal mines.
研究领域:
煤炭科学
·
表面化学
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岩石学
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环境工程
·
分子模拟
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）