FUEL PROCESSING TECHNOLOGY
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2021
·
IF 7.033
Zhong Ma,Guofu Liu,Yonggang Lu,Junfeng Wang,Hui Zhang
In chemical looping combustion , iron-based oxygen carriers often experienced serious phase segregation , which reduced the cyclic stability of the oxygen carriers. In this work, Fe 2 O 3 /Al 2 O 3 (FA) was doped with different metals (Sr, La and Ce) to improve the redox performance during cyclic reactions. The mechanism of dopants on FA was explored by experimental research and characterization analysis. The promotion effect of different dopants on the redox performance of FA followed the sequence: Sr > La > Ce. It was shown that the deactivation of Ce-FA and La-FA was obvious in 20 cycles. The results of 100 successive cycles indicated that the surface structure of Sr-FA remained stable and no sintering was observed. The Sr-FA achieved stable oxygen carrying capacity (4%) in 100 redox cycles. The characterization results indicated that the addition of Sr could effectively increase the concentration of oxygen vacancies , thus inhibiting the phase segregation of FA. The enrichment degree of surface Fe of FA, Sr-FA, La-FA and Ce-FA were 135.7%, 43.47%, 128.0% and 140.0%, respectively. The results of this study provide guidance for the preparation of iron-based oxygen carriers with high redox performance.
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高影响因子
IONICS
·
2021
·Vol. 27
·期 12
·4927-4936
·
IF 2.817
Liu Jiuqing,Song Feifei,Li Qihou,Li Jie,Hong Zikun,Wang Cheng,Liu Meng,Bai Lishun,Zeng Fanli
The polymer separator is part of the gel polymer electrolyte (GPE) and plays a crucial role in battery. In this study, a novel PES-based separator for lithium-oxygen batteries was prepared using non-solvent-induced phase separation (NIPS) technique firstly and modified by doping Al 2 O 3 nanoparticles. It is proved that the properties of the PES/Al 2 O 3 separator are affected by the presence of Al 2 O 3 nanoparticles. The results show that the PES/Al 2 O 3 separator with Al 2 O 3 content of 2 wt% and 4 wt% has lower crystallinity, higher electrolyte uptake, and better mechanical properties and thermal stability than PES-based separator without Al 2 O 3 . The resulting PES/Al 2 O 3 separator containing 4 wt% Al 2 O 3 has higher ionic conductivity (0.49 mS cm −1 ) and lithium ions transference number (0.28). Consequently, the assembled batteries with the PES/Al 2 O 3 separator containing 4 wt% Al 2 O 3 exhibit excellent cycling performance (75 cycles, 1000 mAh g −1 at 0.05 mA cm −2 ). Therefore, PES/Al 2 O 3 separator has a significance meaning in the research of high-safety and long-cycle lithium-oxygen battery.
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高影响因子
ENERGY & FUELS
·
2021
·
IF 3.605
Beibei Feng,Yitong Zhai,Lidong Zhang
The combustion and catalytic combustion of ethanol (a typical bioalcohol) at atmospheric pressure and an equivalence ratio of ϕ = 3 were investigated in a flow reactor. Reactants, important intermediates, and products were detected and identified by gas chromatography–mass spectrometry. For ethanol combustion, the hydrogen abstraction reaction attacked by OH radicals is the initial pathway for ethanol consumption. Acetaldehyde is regarded as an important intermediate in ethanol combustion through kinetic analysis. However, catalytic combustion of ethanol over γ-Al2O3 is dominated by bimolecular and unimolecular dehydration reactions to produce diethyl ether and C2H4, while Pd/γ-Al2O3 can strongly oxidize ethanol to CO2 with a dramatic decrease in the decomposition temperature. To further understand the mechanism of catalytic combustion, pyrolysis and catalytic pyrolysis of ethanol were also explored. The product distribution in catalytic pyrolysis demonstrated weaker coke deposition over γ-Al2O3 in comparison to catalytic combustion. In addition, the deactivation of Pd/γ-Al2O3 at high temperatures was probably due to the increase in the concentration of oxygenated species to cover the active Pd site. The apparent activation energy was estimated by the Arrhenius equation to illustrate the difference in primary reaction channels. This work bridges the gap between combustion and catalytic combustion of ethanol, which is beneficial for the improvement of catalytic performance and control of pollutants by combining pyrolysis and combustion.
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ChemCatChem
·
2021
·Vol. 13
·期 19
·4133-4141
·
IF 5.686
Lina Zhang,Bangjie Zhang,Peng Xue,Jiwei Li,Zhun Zhang,Yanling Yang,Shuai Wang,Jingdong Lin,Honggang Liao,Yong Wang,Yali Yao,Shaolong Wan,Haifeng Xiong
Graphical Room temperature oxidation : Pretreatment methods affect the nature of the Pd species and the reactivity of Pd/Al 2 O 3 in formaldehyde oxidation at room temperature. The steam treatment (H 2 O/Ar) increased the metal Pd dispersion, and generated more active hydroxyl groups, leading to the enhanced reactivity in formaldehyde oxidation. A Pd/Al 2 O 3 nanocatalyst was pretreated at 750 °C in air, Ar or H 2 O/Ar, respectively. The effect of these different pretreatments on the active species and reactivity of Pd/Al 2 O 3 in formaldehyde oxidation at room temperature was investigated. The pretreatment was found to affect both the phase transformation of PdO to Pd metal and the Pd dispersion, leading to different catalytic performances. We found that the Pd/Al 2 O 3 nanocatalyst pretreated in both Ar and H 2 O/Ar show 60 % and 100 % formaldehyde conversion at 25 °C, respectively, while the catalyst pretreated in air is not active under the same condition. Pretreatments in both Ar and H 2 O/Ar were found to facilitate the formation of metallic Pd on Pd/Al 2 O 3 catalyst, confirmed by both experiments and calculation based on the function of the equilibrium oxygen pressure and temperature. We further found that the catalyst pretreated in H 2 O/Ar has higher Pd dispersion and more surface OH groups compared to that pretreated in Ar, leading to improved activity in formaldehyde oxidation.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2021
·
IF 5.316
Xin Huang,Le-Tian Wang,Yan-Fang Song,Fang Ge,Yi Zhang,Xin-Jing Meng,Hong-Hua Ge,Yu-Zeng Zhao
The use of nanofluids as vehicle coolant can significantly improve the heat exchange efficiency, but it is necessary to understand its corrosiveness to metals before use. Corrosion behavior of aluminum alloy in simulated vehicle coolant (SVC), nano Al 2 O 3 coolant (SVC-Al 2 O 3 ), simulated coolant containing sodium dodecyl benzene sulfonate (SVC-SDBS) and nano Al 2 O 3 coolant containing SDBS (SVC-Al 2 O 3 -SDBS) was investigated by electrochemical impedance spectroscopy , polarization curve, weight loss analysis and surface analysis in this paper. The results showed that in the three media of SVC, SVC-SDBS and SVC-Al 2 O 3 -SDBS, the impedance modulus at the frequency of 10 mHz |Z| 0.01 , the charge transfer resistance R ct and the film resistance R f of aluminum alloy electrode increased with the immersion time. Compared with the three media, the aluminum alloy in SVC-Al 2 O 3 medium had the lowest |Z| 0.01 , R ct and R f , and had the highest corrosion current density, implying that Al 2 O 3 nanoparticles promoted the corrosion of aluminum alloy in SVC, and the corrosion products formed on the alloy surface were Al 2 O 3 , Al(OH) 3 , AlOOH, which were loose and not protective. The R f values of aluminum alloy electrode increased significantly with time in the media containing SDBS. The aluminum alloy exhibited the best corrosion resistance in the medium of SVC-SDBS and no obvious loose corrosion products but compact passivation film could be seen on the alloy surface. SDBS exhibited a good corrosion inhibition effect on aluminum alloy, which may be due to the adsorption of SDBS on the metal surface and the fact that SDBS promoted the formation of the passive film by preventing the transformation of alumina film to loose AlOOH layer. In the medium containing both SDBS and Al 2 O 3 nanoparticles, the corrosion inhibition effect of SDBS was weakened. This maybe due to the electrostatic attraction of positively charged Al 2 O 3 nanoparticles and negatively charged SDBS, which reduced the adsorption of SDBS on the metal surface, thereby weakening the protective effect of SDBS on the metal surface.
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FUEL PROCESSING TECHNOLOGY
·
2020
·
IF 4.982
Muhammad Masood Khan,Lijun Jin,Muhammad Mahmood Khan,Yang Li,Hammad Saulat,Yun Zhang,Muhammad Sarfraz,Jialong Zhu,Haoquan Hu
The composite catalysts AC-Ni/MgO-Al 2 O 3 were prepared by the co-precipitation method with activated carbon (AC) and [Ni,Mg,Al]-hydrotalcite as the precursors, and characterized by XRD , TG-DTG, N 2 adsorption, H 2 -TPR and SEM, respectively. The resultant catalysts were examined for CO 2 reforming of methane. The results showed that the introduction of AC into Ni/MgO-Al 2 O 3 catalyst improved the textural properties, especially the surface area and pore volume of mesopores , and decreased the size of metal Ni. Compared with Ni/MgO-Al 2 O 3 , the composite AC-Ni/MgO-Al 2 O 3 exhibited higher catalytic activity , stability and H 2 /CO ratio. But the AC content obviously influenced the catalytic performances. High AC loading resulted in the decline of catalytic activity owing to lower surface area and fewer active Ni content in the catalyst. 10AC-Ni/MgO-Al 2 O 3 with 10% AC displayed the best catalytic activity and stability compared with Ni/MgO-Al 2 O 3 . About 86.2% conversion of CH 4 , 91.3% conversion of CO 2 and above 0.95 ratio of H 2 /CO were achieved over 10AC-Ni/MgO-Al 2 O 3 sample for the reaction time of 5430 min. This work provides a route to improve catalytic performances of Ni-based catalysts in CO 2 reforming of methane.
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METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2020
·Vol. 52
·期 1
·314-321
·
IF 2.035
Ren Guoxing,Xiao Songwen,Xia Longgong,Liao Caibin,Liu Zhihong
To obtain fundamental information on the dissolution of cobalt into alumina-saturated MnO-SiO 2 -Al 2 O 3 slags in the smelting reduction of spent lithium-ion batteries, the equilibrium distribution of cobalt between Co-Cu alloys and alumina-saturated MnO-SiO 2 -Al 2 O 3 slags was measured at 1573 K and 1623 K under a controlled CO-CO 2 atmosphere. The results show that (i) the solubility of cobalt in the slag increased with increasing concentration of cobalt in the alloy and increasing oxygen partial pressure in the atmosphere at a fixed concentration of cobalt in the alloy, and (ii) the activity coefficient of CoO in the slag increased with increasing cobalt oxide in the slag. The activity coefficient of CoO in the slag, γ CoO, referred to as solid CoO, can be described as a function of the concentration of CoO in slag as follows: γ CoO = 11.2957(wt pct CoO in slag) + 12.0944 (1573 K, (wt pct MnO)/(wt pct SiO 2 )= 0.76–0.83); γ CoO = 2.2286(wt pct CoO in slag) + 4.5232 (1623 K, (wt pct MnO)/(wt pct SiO 2 )= 0.78–0.85).
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高影响因子
APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Huifang Wang,Jun Zhang,Qichong Zhang,Hao Wu,Xiaohong Xu
The p-n heterojunctions with the built-in electric field are often adopted to promote the separation of photoexcited electron-hole pairs and enhance the photoelectrochemical (PEC) performance. However, the interface states often affect the band alignment of ZnO/Cu 2 O heterointerface and cause the decline of PEC performance. In this study, the ultrathin insulating Al 2 O 3 layer was introduced to modify the interface between n-type ZnO nanorod arrays (NRA) and p-type Cu 2 O. Compared to that of ZnO NRA/Cu 2 O, the photocurrent density is significantly improved and onset potential shifts negatively for ZnO NRA-Al 2 O 3 /Cu 2 O. The Al 2 O 3 ultrathin layer is deemed to suppress the photoexcited carriers trapped by the heavy interface defect states via improving the interface quality and block the recombination between electrons in the conduction band of ZnO NRA and holes in the valence band of Cu 2 O. This work broadens the interface modification method of p-n heterojunction and its results are favorable for photovoltaic devices, photodetection and PEC water splitting applications.
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高影响因子
CELLULOSE
·
2021
·Vol. 28
·期 3
·1541-1553
·
IF 5.044
Yin Yanan,He Jiacheng,Zhang Chenggang,Chen Jisi,Wu Jinxing,Shi Zhuqun,Xiong Chuanxi,Yang Quanling
Abstract Flexible dielectric materials with high energy density and remarkable charge–discharge efficiency are currently in great demand for the field of energy storage. On the other hand, it is also urgent to develop renewable, biodegradable and environmentally friendly dielectric materials. In this work, Al 2 O 3 nanoparticles (AO) with a diameter of ~ 10 nm were incorporated into regenerated cellulose matrix (RC) without extra treatment to fabricate environment-friendly RC–AO dielectric nanocomposites via a simple dissolution/regeneration pathway. Effects of Al 2 O 3 nanoparticles on the structure and dielectric properties of RC–AO nanocomposite films were systemically investigated. The results showed that the RC–AO films exhibited excellent comprehensive performance, including increased dielectric constant, reduced dielectric loss, improved breakdown strength and high energy storage density. Particularly, the high energy density of 5.7 J cm −3 was achieved at the breakdown strength of 380 MV m −1 when the Al 2 O 3 content was 5 wt%. Furthermore, the composites possessed excellent thermal conductivity, stability and mechanical property. This work provides a good choice for the development of high-performance and ‘green’ natural polymer-based dielectric materials. Graphic abstract
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高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Meng Chen,Wei Lu,Hejun Zhu,Leifeng Gong,Ziang Zhao,Yunjie Ding
Linear α-olefins (C8–C12 α-olefin, LAOs) are acknowledged as high-value-added chemicals in both lubricant production and the polyolefin industry. An alternative route to the synthesis of high-purity LAOs is the dehydration of linear long-chain n-alcohols, whereas elevating the activity and selectivity of catalysts remains a challenge. Herein, we presented that on using sodium-modified γ-Al2O3 as the catalyst, a high selectivity (up to 96.87%) to 1-decene was achieved, and an optimized experimental condition (329 °C and 0.25 h–1) was found using the response surface method. Characterization results including X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), pyrolysis (Py)-IR, NH3-temperature-programmed desorption (TPD), and CO2-TPD showed that a suitable ratio (∼0.4 wt %) of sodium impregnation could inhibit the strong acid sites of the catalyst, and sodium impregnation led to the formation of additional base sites, which accounted for the synergistic effect with other acid sites to promote further conversion of ethers to olefins. This work is of significance for the synthesis of LAOs from long-chain n-alcohols.
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2020
·
IF 16.683
Xiucheng Sun,Jian Lin,Yuehan Wang,Lin Li,Xiaoli Pan,Yang Su,Xiaodong Wang
Inert substrate supported Ir catalyst for room-temperature oxidation of formaldehyde has never been reported so far. Here, a novel Ir-based catalyst supported on commercial γ-Al 2 O 3 (IrAl-CD), which was synthesized via a modified colloid-deposition method, can realize complete conversion of HCHO at 20 °C for the first time. It exhibits a two-fold higher specific rate than IrAl-DP prepared by a conventional deposition-precipitation method. Detailed characterizations demonstrate that the positive Ir species bonded with OH groups on IrAl-DP make HCHO oxidation follow a reaction pathway between OH and formate intermediates. In contrast, the fairly high content of metallic Ir 0 species on IrAl-CD facilitates the direct dehydrogenation of HCHO to form the dominant intermediates of CO, which are easily oxidized with a lower activation energy. Consequently, the electronic state of Ir determines the extremely high performance even supporting on inert substrate and the reaction mechanism for HCHO oxidation at ambient temperature.
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高影响因子
Catalysts
·
2020
·Vol. 10
·期 2
·143
·
IF 3.52
Chengxiong Wang,Dezhi Ren,Junchen Du,Qinggao Qin,Aimin Zhang,Li Chen,Hao Cui,Jialin Chen,Yunkun Zhao
Ceria-modified Pt/Al2O3catalyst has been commonly prepared by the impregnation of platinum on ceria-modified alumina and widely applied in the chemical industry and automotive industry. The in situ diffuse reflectance infrared Fourier transformed spectroscopy (DRIFTS), and thermogravimetric (TG) analysis techniques were employed to investigate the typical mechanisms of the bis(ethanolammonium)hexahydroxyplatinate(IV) and cerium nitrate decomposition catalyzed by Ptδ+species for the facile synthesis of CeO2-Pt/Al2O3catalyst. It was found that Pt4+-catalyzed decomposition of cerium nitrate leads to the higher dispersity of ceria and forming more active oxygen species, on the basis of X-ray diffraction (XRD) and H2temperature-programmed reduction (H2-TPR) results. The in situ activity measurements were also performed to investigate the reaction mechanisms and the specific activities for the catalytic CO, NO, C3H6and C3H8co-oxidation. The results indicate that undesirable N2O by-product is formed by the selective catalytic reduction (SCR) of NO by C3H6below 350 °C. The cerium addition effectively improves the activity of catalytic oxidation, but exhibits an increased N2O yield, due to the increased reducibility.Keywords:platinum;ceria;in situ characterization;catalytic oxidation
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