JOURNAL OF HAZARDOUS MATERIALS
·
2022
·
IF 14.224
Xiao-Li Zhou,Pin-Jing He,Wei Peng,Shou-Xin Yi,Fan Lü,Li-Ming Shao,Hua Zhang
Polyvinyl chloride (PVC) is one of the most commonly used plastics. The treatment and recycling of PVC waste is still challenging, due to its non-biodegradability, low thermal stability, high Cl content and low product value. In this study, a one-pot method was developed to upcycle PVC into valuable carbon materials, pipeline-quality pyrolysis gas and chlorides. The well-designed process included dechlorination by Cl-fixative (ZnO or KOH), carbonization of dechlorinated polyenes, and modification of carbon materials in sequence. ZnO and KOH converted 84.48% and 94.15% of total Cl into corresponding chlorides, respectively. CH 4 and H 2 accounted for 81.87–99.34 vol% of pyrolysis gas with higher heat values of 30.11–32.84 MJ m −3 , which can be used as substitute natural gas. As high as 83.13% of the C element was converted into carbon materials. The morphology, structure and property of carbon materials can be modified by different Cl-fixatives. Millimeter-scale carbon spheres with mono-dispersity and porous carbon with a high specific surface area of 1922 m 2 g −1 were obtained when ZnO and KOH were added, respectively. Moreover, the reaction mechanisms of PVC with Cl-fixatives were also deciphered through thermogravimetric analysis and thermodynamic simulation.
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PubMed
高影响因子
FUEL
·
2022
·
IF 8.035
Kun Zhao,Xiaojie Fang,Chaoxian Cui,Shunshun Kang,Anqing Zheng,Zengli Zhao
Chemical looping steam reforming of methane (CL-SRM) is a novel process for the co-production of syngas and hydrogen without an additional purification process. However, the high activity of oxygen carriers is always accompanied by severe carbon deposition via the catalytic cracking of methane, which can result in the rapid deactivation of oxygen carriers and the production of low purity hydrogen. Herein, a series of novel composite oxide carriers of CeO 2 /La 0.9 Sr 0.1 Fe 1−x Ni x O 3 with varying doping ratios of Ni are developed to achieve selective and stable production of syngas and H 2 . The redox performance of CeO 2 /La 0.9 Sr 0.1 Fe 1−x Ni x O 3 was evaluated in a fixed bed reactor coupling with various analytical methods. It is found that the Ni doping ratio of 0.2 can significantly enhance the performance and stability of CeO 2 /La 0.9 Sr 0.1 Fe 1−x Ni x O 3. It is speculated that the proper doping ratio of Ni can simultaneously improve the surface lattice oxygen vacancies and the lattice oxygen migration rate. The CH 4 reforming over CeO 2 /La 0.9 Sr 0.1 Fe 0.8 Ni 0.2 O 3 displays a very stable performance while avoiding obvious carbon deposition within 20 min, in which, the CH 4 conversion, H 2 selectivity , and CO selectivity achieve 85%, 96%, and 88%, respectively. The yield of H 2 (>95% purity) reaches 23 mL/min in the subsequent steam oxidation of reduced CeO 2 /La 0.9 Sr 0.1 Fe 0.8 Ni 0.2 O 3 . Its lattice oxygen can be completely recovered by the final air oxygenation. The CeO 2 /La 0.9 Sr 0.1 Fe 0.8 Ni 0.2 O 3 exhibits high reactivity and stability in 10 redox cycles at 850 °C. These results demonstrate that the doping of Ni affords an efficient manner to regulate the lattice oxygen migration rate of perovskite oxides to match the surface reaction rate, thereby avoiding the deep reduction of surface metal ions within perovskite oxides and resulting carbon depositions during CL-SRM.
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Nano Research
·
2020
·Vol. 13
·期 12
·3206-3211
·
IF 8.183
Zhang Meng,Hu Zheng,Gu Lin,Zhang Qinghua,Zhang Linghui,Song Qian,Zhou Wei,Hu Shi
A series of carbon-based binary single-atom catalysts of Fe and Ni coordinated by nitrogen are fabricated using a glucose-chelating method. Depending on the Ni/Fe content, they exhibit a wide-range of controllable CO/H 2 ratio from 0.14 to 10.86, which is meaningful to specific chemical processes. The durability of the catalyst is evaluated over an 8-hour period with no significant degradation of activity. The variation of the faradaic efficiency with Ni/Fe content is justified by density-functional-theory based calculation of the reaction barrier in both hydrogen evolution and CO 2 reduction reactions.
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ACS Catalysis
·
2024
·
IF 11.3
Yuanjie Xu,Jikang Yao,Hongqiao Lin,Qian Lv,Bo Liu,Lizhi Wu,Li Tan,Yihu Dai,Xupeng Zong,Yu Tang
Enhancing catalyst durability is a critical concern in the partial oxidation of methane (POM) to syngas since the reaction is operated at high temperatures (>600 °C). Alongside sintering and coke deposition, the deactivation of the supported Ni catalyst is often due to the in situ oxidation of active metallic nanoparticles into inactive cations during the POM reaction. Herein, a Ni/BN catalyst was developed by introducing functional CeOx as a promoter to stabilize the Ni sites. The optimized 4Ni/7.5Ce/BN catalyst, comprising 4 wt % Ni and 7.5 wt % Ce on BN, exhibits enhanced stability during continuous testing at 600 °C for 125 h without any deactivation, which is comparable to that of noble metal catalysts. Comprehensive investigations reveal that maintaining the metallic state of Ni under reaction atmosphere is crucial for the stability of the catalyst. The construction of CeOx on BN effectively inhibits migration and oxidation of the catalytically active Ni0 species.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2025
·
IF 6.2
Mingqiang Chen,Quan Wang,Defang Liang,Yishuang Wang,Chang Li,Xuemei Shen,Chunyue cheng,Jun Wang
Herein, a series of Fe-based biochar catalysts (xFe/WSBC) were synthesised via impregnation using wheat straw as a carbon precursor and applied to the Fischer–Tropsch synthesis of olefins (FTO) from syngas. Various characterisations of fresh catalysts demonstrated that Fe content significantly affected the dispersion of iron particles and the surface distribution of Fe 3 + /Fe 2+ . Among the samples, 5Fe/WSBC exhibited the highest surface Fe 3+ /Fe 2+ ratio and thus the lowest surface electron density, which enhanced the adsorption and activation of H 2 . In addition, an appropriate amount of the Fe additive (5 wt%) significantly decreased the Fe 3 O 4 particle size, which promoted the continuous reduction and carbonisation processes during FTO to generate iron carbide phases, which boosted CO activation and the subsequent C–C coupling. Therefore, 5Fe/WSBC exhibited the highest CO conversion (46.9 %) and iron time yield (348.9 μmol CO ·g Fe −1 ·s −1 ) as well as the major enhancement of selectivity to light olefins (C 2 = –C 4 = ). The results for the used catalysts demonstrated that 5 wt% Fe clearly inhibited the sintering of iron particle size and improved the catalytic stability of FTO.
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高影响因子
ENERGY
·
2024
·
IF 9
Xu Zhang,Qing Wang,Da Cui,Jingru Bai,Yuqi Wang,Jinghui Zhang
Hydrogen-rich syngas from supercritical water gasification (SCWG) of renewable biomass is a promising technology. However, the mechanistic studies related to experiments and simulations on hemicellulose, an important component of biomass, are still limited. Therefore, in this study, the SCWG mechanism of hemicellulose was investigated using a batch reactor and via ReaxFF molecular dynamics simulations. The results indicated that the long chains of xylan broke to short chains during the heating process, which was accompanied by the occurrence of ring-opening reactions. SCWG occurred more completely with increasing temperature or decreasing concentration, when hydrogen was more selective and methane was produced mainly by gas reforming reactions. At 600 °C and 5 g/100 g water, the total gas yield of xylan SCWG was 38.65 mmol g −1 , and the hydrogen yield could reach 14.48 mmol g −1 . The liquid products mainly included furfural and phenol . The solid products consisted of a high C content, which could reach more than 90 % at 500 °C, and were dominated by polycyclic aromatic hydrocarbons, and at 600 °C by benzene and naphthalene . Xylan formed carbon balls on the surface of the solid products, while hemicellulose exhibited the formation of a dense porous structure.
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ACTA PHYSICO-CHIMICA SINICA
·
2017
·Vol. 33
·期 8
·1672-1680
·
IF 0.767
LIAO Pei-Yi,ZHANG Chen,ZHANG Li-Jun,YANG Yan-Zhang,ZHONG Liang-Shu,GUO Xiao-Ya,WANG Hui,SUN Yu-Han
A series of Cu/Co/Mn/Al catalysts derived from hydrotalcite precursors with different Cu/Co molar ratios (0, 0.1, 0.5, 1.0, and 2.0) were prepared and used for the synthesis of higher alcohols from syngas. N2 physical adsorption desorption, inductively coupled plasma atomic
emission spectrometry (ICP-AES), X-ray diffraction (XRD), scanning electron microscopy (SEM), hydrogen temperature-programmed reduction (H2-TPR), thermogravimetry (TG), and high-resolution transmission electron microscopy (HRTEM) techniques were employed to investigate the physical
and chemical properties of the Cu/Co/Mn/Al catalysts. The results show that the optimum Cu content can increase specific surface area, improve reducibility, and form regular layered structure to provide more uniform distribution of active sites, thereby enhancing catalytic activity and alcohol
selectivity. When the Cu/Co molar ratio was 0.5, the yield of alcohol and the alcohol selectivity reached the maximum values of 0.071 g·g-1·h-1 and 35.9%, respectively.
研究领域:
催化化学
·
材料科学
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Fanhui Meng,Lina Wang,Muhammad Asif Nawaz,Qian Wang,Zhiyuan Gong,Zhong Li
Direct conversion of syngas to light hydrocarbons has been intensively studied in recent years; however, the high selectivity of light hydrocarbons is still a challenging task to achieve a high CO conversion. Here, a bifunctional catalyst consisting of a methanol synthesis catalyst (CZA) and a methanol to dimethyl ether (DME) catalyst (Al 2 O 3 ) was employed with a hydrocarbon synthesis catalyst (SAPO-34), for syngas conversion to light hydrocarbons in a dual fixed-bed reactor. The conversion of simulated intermediates CO/CO 2 /DME/N 2 /H 2 with a molar ratio of 9/6/4/5/76, obtained from syngas conversion to DME over CZA and Al 2 O 3 , was studied over SAPO-34 zeolites. It was found that SP34-0.1 with Si/Al ratio of 0.1, exhibited low amount of strong acid (0.60 mmol/g) and high selectivity to light olefins (74.1%), while SP34-0.4 with Si/Al ratio of 0.4 exhibited high amount of strong acid (1.00 mmol/g) leading to high selectivity of light paraffins (88.4%). The in-situ DRIFTS analysis illustrated that DME can be rapidly adsorbed on the hydroxyl site of SAPO-34 and decomposed into the surface methyl species, where SP34-0.4 could produce more dimethylcyclopentenyl cationic species than SP34-0.1. It was suggested that the overall reaction route led to a high selectivity to light olefins (84.2%) with a CO conversion of 61.2% on (CZA + Al 2 O 3 ) catalyst combined with SP34-0.1, while a high selectivity to light paraffins (76.3%) could be achieved by combining with SP34-0.4 at 70.3% CO conversion. Since, the current study interprets that the selectivity of hydrocarbons can be adjusted by regulating the acidity of SAPO-34 to achieve a high CO conversion in the dual fixed-bed reactor scheme.
研究领域:
化学工程
·
催化科学
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JOURNAL OF THE ENERGY INSTITUTE
·
2024
·
IF 5.6
Mingxuan Zhong,Chenxuanzi Wang,Jiajun Xu,Yongcheng Cai,Bo Xiao,Tingting Xu,Xun Wang
Sr–Fe oxides are suitable oxygen carriers (OCs) with excellent cyclic stability. However, the moderate redox activity causes a deficiency in H 2 yield in chemical looping reforming coupled with water splitting (CLR-WS) process. Herein, we designed and prepared the composite xNiFe 2 O 4 /(1-x)SrFe 12 O 19 OCs by ball milling method, which exhibited both high redox activity and high cyclic stability during reactions. A series of characterizations showed that the introduction of NiFe 2 O 4 promoted the oxygen vacancy formation and the release of lattice oxygen, facilitating the reforming of bioethanol in fuel reactor (FR). During CLR-WS process, a high carbon conversion of 79.20 % and a H 2 yield of 13.23 mmol/g OC were achieved by 3Ni7Sr OC at 800 °C, outperforming that of the conventional SrFe 12 O 19 OC. Moreover, the severe carbon deposition and sintering issues inherent to NiFe 2 O 4 were avoided due to the presence of Sr. All Sr-containing composite OCs showed H 2 purity exceeding 99.26 % and excellent cycling stability with no apparent activation of oxygen transport capacity over 3000 min redox reactions.
研究领域:
化学工程
·
材料科学
·
能源工程
·
环境工程
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高影响因子
JOURNAL OF RARE EARTHS
·
2026
·
IF 9.6
Zhengyang Chi,Yonghong Niu,Lin Ma,Yuan Tian,Hao Li
The global transition toward low carbon energy systems has intensified the demand for renewable H 2 and cleaner syngas production. Biomass steam gasification is a promising route, but tar formation and catalyst deactivation still limit its practical application. Herein, Pr 1– x Ce x FeO 3 supported on calcined dolomite was developed for staged biomass steam gasification to couple H 2 production with tar reforming. Statistical screening identifies gasification temperature, Ce substitution level, and steam flow rate as the dominant factors controlling H 2 formation. Under single-factor conditions, Pr 0.6 Ce 0.4 FeO 3 /CD shows the best performance, giving 44.33 vol% H 2 , a total gas yield of 1.51 Nm 3 /kg biomass, a syngas yield of 1.10 Nm 3 /kg biomass, and a syngas fraction of 72.77 vol%. Tar conversion is optimal near 850 °C, where the dry tar yield decreases to 22.75 g/kg biomass, while heavy polycyclic aromatics and >C13 compounds account for 0.79% and 4.14% of the total gas chromatography-mass spectrometry (GC-MS) peak area, respectively. Response surface optimization gives an optimum at 810 °C, x = 0.4, and a steam flow rate of 1.2 mL/min, with an experimental H 2 fraction of 46.22 vol%. Structural and surface analyses indicate that moderate Ce substitution preserves the perovskite framework while regulating defect formation, surface oxygen species, and Fe/Ce/Pr redox behavior. Cycling deactivation is mainly associated with carbonaceous deposits, Fe migration, CaO carbonation, and structural densification. This work provides a feasible perovskite dolomite strategy for integrated tar reforming and production of syngas rich in H 2 from biomass.
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高影响因子
JOURNAL OF THE ENERGY INSTITUTE
·
2024
·
IF 5.6
Chenlong Liu,Yijun Zhang,Yiman Xiao,Ruyue Zhang,Siddig Abuelgasim,Chenghua Xu,Atif Abdalazeez
Bio-oil by-products are inevitable with biomass gasification. It is considered a potential resource for hydrogen production via steam reforming. This study investigated acetic acid as a bio-model compound using a NiAl 2 O 4 catalyst. The effect of reaction conditions on hydrogen-rich production has also been discussed, including reaction time (1 h, 3 h, 5 h and 7 h), steam/carbon ratio (S/C = 1–4) and the blend of NiAl 2 O 4 and CaO (1:0, 3:1, 1:1, 1:3 and 0:1). The fresh and spent samples were characterized by XRD, XPS, SEM, BET, etc. The result showed that the CaO addition has several advantages: 1) it increases hydrogen gas purification; 2) it prevents Ni separation from NiAl 2 O 4 ; 3) it decreases the sintering of NiAl 2 O 4 . However, Ca 5 Al 6 O 14 formation decreases the activity of hydrogen production. In reaction conditions, steam is an essential factor for hydrogen gas production. The S/C ratio = 3 shows the optimum result for hydrogen gas production. Although the higher S/C ratio = 4 can maintain the adsorption activity of CaO, it causes Ni separation from NiAl 2 O 4 . The blend of NiAl 2 O 4 and CaO is another essential factor for hydrogen gas production. Adding CaO has increased hydrogen gas production significantly. However, a little CaO in a blend ratio 3:1 does not maintain the stability of the NiAl 2 O 4 structure. In the end, the optimum conditions are S/C ratio = 3 and blend = 1:1 at 650 °C, which produces hydrogen gas yield (2.1 mol/mol) and H 2 /CO (5.83).
研究领域:
能源科学
·
催化化学
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高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Hongbin He,Xuan Jian,Tianxu Zen,Bingbing Feng,Yanan Hu,Zhongqiang Yuan,Zizhen Zhao,Xiaoming Gao,Lei Lv,Zhenheng Cao
The rapid recombination of interfacial charges is considered to be the main obstacle limiting the photocatalytic CO 2 reduction. Thus, it is a challenge to research an accurate and stable charge transfer control strategy. MIL-53 (Al)-S/Cd 0.3 Zn 0.7 S (MAS/CZS-0.3) photocatalysts with chemically bonded interfaces were constructed by in-situ electrostatic assembly of sulfur defect Cd 0.3 Zn 0.7 S (CZS-0.3) on the surface of MIL-53 (Al) (MAW), which enhanced interfacial coupling and accelerated electron transfer efficiency. An adjustable proportion of syngas (H 2 /CO) was prepared by photothermal catalytic CO 2 reduction at micro-interface. and the optimal yield of CO (66.10 μmol∙g −1 ∙h −1 ) and H 2 (71.0 μmol∙g −1 ∙h −1 ) was realized by the MAS/CZS-0.3 photocatalyst. The improved activity was due to the photogenerated electrons migrated from CZS-0.3 to the adsorption active sites of MAS , which strengthened the adsorption and activation of CO 2 on MAS. The photothermal catalytic CO 2 reduction to CO follows the pathway of CO 2 →*COOH → CO and CO 2 →*HCO 3 – →CO. This work provided a reference for the research, characterization, and application of in-situ anchoring of metal organic frameworks in photothermal catalytic CO 2 reduction, and provided a green path for the supply of Syngas in industry.
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高影响因子
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