FUEL
·
2022
·
IF 8.035
Xinyu Yang,Zezhi Chen,Huijuan Gong,Feng Lin,Tingting Zhu,Ziyi Yang
Deoxygen is a crucial step for landfill gas (LFG) recycling and purification. Pt/γ-Al 2 O 3 is the most active catalyst for LFG deoxygen via catalytic methane oxidation . It is challenging but significant to further improve the performance of this type of catalyst. In regard of homogeneous and heterogeneous activation of methane by superacids , here we demonstrate LFG deoxygen via catalytic methane oxidation using a solid superacid catalyst, Pt/SO 4 2- /Al 2 O 3 , synthesized using pre-sulfated γ-Al 2 O 3 support by impregnated with sulfuric acid . In comparison to Pt/γ-Al 2 O 3 , Pt/SO 4 2- /Al 2 O 3 catalysts exhibit exceptionally improved activity and minimum complete O 2 conversion at a temperature of 264 ℃, a decrease of about 51 ℃. This value is superior to the state-of-the-art Pt-based deoxygen catalysts. Characterizations and theoretical calculations indicate that sulfation enhances the amount of acid sites on γ-Al 2 O 3 support and induces electron deficiency of the supported Pt species (+0.28|e|), thus boosting the low-temperature activity. Furthermore, the Pt/SO 4 2- /Al 2 O 3 catalyst maintained its initial activity after six runs without any detectable coke deposition. This discovery offers simple and effective strategies to precisely design higher performance application-oriented Pt based deoxygen catalysts.
研究领域:
催化
·
环境工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2019
·
IF 5.128
Xue-Ke Li,Zhi-Min Zong,Yi-Feng Chen,Zheng Yang,Guang-Hui Liu,Fang-Jing Liu,Xian-Yong Wei,Bao-Jun Wang,Feng-Yun Ma,Jing-Mei Liu
A highly active difunctional Ni-Mg 2 Si/γ-Al 2 O 3 was prepared by thermally decomposing nickel tetracarbonyl onto γ-Al 2 O 3 impregnated with Mg 2 Si. The non-catalytic hydroconversion (NCHC) and catalytic hydroconversion (CHC) of the extract ( E ) and extraction residue (ER) from Yinggemajianfeng lignite were investigated over Ni-Mg 2 Si/γ-Al 2 O 3 at 240 °C in n -hexane. Benzyloxybenzene and oxybis(methylene)dibenzene were used as lignite-related model compounds to speculate the possible mechanisms for the catalytic hydrocracking and hydrogenation over Ni-Mg 2 Si/γ-Al 2 O 3 . As a result, more organic matter in ER was converted to soluble portion (SP) by the CHC than by the NCHC. The main SP from the CHC are chain alkanes and cyclanes, while that from the NCHC is rich in arenes and oxygen-containing organic compounds. The results indicate that Ni-Mg 2 Si/γ-Al 2 O 3 effectively catalyze the hydrocracking of >C alk –O– linkages and the hydrogenation of aromatic rings in E and ER.
研究领域:
化学工程
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NON-CRYSTALLINE SOLIDS
·
2017
·
IF 2.124
Ren Gao,Huanping Wang,Qingong Zhu,Qinghua Yang,Xingguo Sun,Bingpeng Li,Shiqing Xu,Xianghua Zhang
The glasses of 93.9% ( x SiO 2 - y Al 2 O 3 - z MgO)-5% CaO-1% B 2 O 3 -0.1% Fe 2 O 3 were prepared, and the relationship between mechanical properties and structural stability were characterized by means of Raman spectroscopy and optical band gap values. The glass forming region is found to be x = 50–70%, y = 10–25% and z = 15–32%. As x = 65%, y = 10% and z = 25% (SAM-4), the investigated glass possesses the optimum volume density, oxygen packing density, optical band gap, banding strength , compression strength and compression modulus, which are 2.517 g/cm 3 , 77.047 mol/l, 3.56 eV, 77.04 MPa, 202.74 MPa and 106.70 GPa, respectively. Meanwhile, starting from the representative point of SAM-4 to radiate around, the volume density, oxygen density, Raman intensity and mechanical properties of the glasses are all decreasing constantly, and the optical band gap of the glasses is increasing on the contrary. Moreover, the optical band gap value and Raman spectroscopy of SAM-4 all prove that the number of oxygen bonds in the bridge reach the maximum and the highest structural stability is achieved, which further shows that it is an important reason why its mechanical properties is significantly improved.
研究领域:
材料科学
·
玻璃科学
·
光谱学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2023
·Vol. 20
·期 6
·3635-3646
·
IF 2.1
Haopeng Cai,Yinglong Wei,Baoguo Wang,Kun Jiang
It is necessary to give self-healing function to ceramic materials because of their notch sensitivity. In the past, studies on self-healing ceramics have mainly focused on the high-temperature stage, and less research has been done below 1000°C. In this study, SiC/Al 2 O 3 /TiB 2 ceramic composites were prepared by spark plasma discharge sintering, and cracks were introduced on the surface of the polished specimens. Crack healing at 600°C–800°C was investigated, and the recovery of macroscopic bending strength and the change of microscopic crack morphology after heat treatment were used to evaluate the crack-healing effect. It was found that the surface cracks of the material were completely filled and healed by oxidation products after heat treatment at 700°C for 60 min, and the highest healing efficiency exceeded 95% for both specimens with different crack lengths, and the main mechanism of crack by Si-Al-B-Na-Ca-O type glass produced by the reaction of TiB2 and a small amount of SiC with oxygen to produce oxides and glass powder. Good healing effect and fast healing speed effectively improve the service life and reliability of ceramic materials, which has very far-reaching significance for the practical application with ceramic materials.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
PROGRESS IN REACTION KINETICS AND MECHANISM
·
2017
·
IF 0.682
Hua Song,Shengnan Li,Hualin Song,Feng Li,Huapeng Cui
A number of Zn–S2O82–/ZrO2–Al2O3 (Zn(x)–SZA) catalysts with different Zn mass fractions were synthesised and characterised by using X-ray diffraction, the Brunauer–Emmett–Teller method, and H2 temperature-programmed reduction. The structure and isomerisation performance of Zn(x)–SZA catalysts were studied using n-pentane as a probe reaction. The results showed that a pure tetragonal ZrO2 phase was formed on Zn(x)–SZA, and the ZrO2 crystallite sizes of the tetragonal phase increased in the order: Zn(0.5)–SZA < Zn(1.0)–SZA < Zn(1.5)–SZA < Zn(2.0)–SZA < SZA. Zn can strengthen the interaction between persulfate ions and the support, promote the formation of stronger acidity, lead to a better dispersion of sulfate ions on the surface, and improve the redox performance of the catalysts. The Zn(1.0)–SZA catalyst exhibited the best catalytic activity for n-pentane isomerisation. At a temperature of 170 °C, a reaction pressure of 2.0 MPa, a molar H2/n-pentane ratio of 4:1, and a weight hourly space velocity of 1.0 h−1, the isopentane yield reached 58.0%.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 29
·期 56
·84166-84179
·
IF 5.19
Gao Panting,Li Yuran,Lin Yuting,Chang Liping,Zhu Tingyu
Catalytic hydrolysis of carbonyl sulfur (COS) from blast furnace gas is one of the keys to achieving ultra-low emission in the iron–steel industry. To improve the COS hydrolysis activity on γ-Al 2 O 3 catalyst at low temperature, catalysts with Fe or La as the active component were prepared by the impregnation method, the physical and chemical properties of the catalyst were characterized by ICP, XRF, XRD, BET, and TPD. The hydrolysis activity of COS and sulfur resistance ability on various catalysts were investigated in a fixed bed reactor combined with gas chromatography. The results show that the addition of Fe or La improves the COS hydrolysis activity due to the increase in alkaline sites on the catalyst surface. The roles of various alkaline sites on catalysts have been recognized. The weak alkaline center is the reaction site of COS hydrolysis, the middle and strong alkaline centers are the adsorption and oxidation sites of H 2 S. The Fe/Al 2 O 3 catalyst has higher hydrolytic activity and oxidative capacity for H 2 S removal due to forming more sulfate species on Fe. The La/Al 2 O 3 catalyst has higher hydrolysis efficiency in that H 2 S rapidly desorbs from the catalyst surface to the gas phase, and then, the activity of reaction sites is recovered. This provides an idea for the preparation of sulfur-resistant catalysts.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
Materials Today Communications
·
2024
·
IF 3.7
Yi Liu,Bang Lan,Wenhong Ruan,Mingqiu Zhang
Recently, soaring developments in 5 G technology have raised an intensive challenge in developing polymer composites with excellent thermal conductivity and dielectric properties . Herein, Al 2 O 3 @Si/MPPO composites were developed through synergistic modification and solution mixing methods. The double bond reaction between Al 2 O 3 @Si and MPPO enhanced the interfacial force and greatly reduced the interfacial thermal resistance and interfacial polarization, leading to highly thermally conductive composites with excellent dielectric properties. The resultant polymer composites exhibited high thermal stability, excellent dynamic mechanical properties, a low dielectric loss of 0.00292, and a high thermal conductivity (TC) of 1.49 W/(m·K), which was 5.21 times higher than that of the pure MPPO resin, making it an ideal thermal management material for electronic devices.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
POLYMER COMPOSITES
·
2024
·Vol. 45
·期 12
·11112-11124
·
IF 4.8
Jian Qiao,Yang Lv,Yun Chen,Wei Yang,Chong Zhang,Xin Chen,Chunyu Wong,Qing Liu,Jibao Lu,Tao Zhang,Xiaoliang Zeng,Rong Sun
The relationship between interfacial structure and thermal conductivity in epoxy resin/Al 2 O 3 composite is important but is still elusive. Here, we illuminate this issue by investigating the role of four silane coupling agents in thermal conductivity for epoxy resin/Al 2 O 3 composites. The results show that 3-glycidoxypropyltrimethoxysilane (KH560) is the best silane coupling agent to modify Al 2 O 3 , resulting in the lowest viscosity and the highest thermal conductivity of the epoxy resin/Al 2 O 3 -KH560 composite compared with alternative systems. This is attributed to the strong interfacial interaction between Al 2 O 3 -KH560 and epoxy resin, as confirmed by the Fowkes model and broadband dielectric spectroscopy. The interfacial thermal resistance between the epoxy resin and Al 2 O 3 is also quantitatively measured via a photothermal radiometry technique. The epoxy resin/Al 2 O 3 -KH560 also has the lowest interfacial thermal resistance (1.50 ± 0.02 × 10 −6 m 2 K W −1 ), compared with the other three systems. This study advances the understanding of the relationship between interfacial structure and thermal conductivity in polymer composites. Highlights The relationship between interfacial structure and thermal conductivity in epoxy resin/Al 2 O 3 composite is understood. The interfacial structure is characterized by broadband dielectric spectroscopy. The interfacial thermal resistance is quantitatively measured via a photothermal radiometry technique.
研究领域:
材料科学
·
热传导工程
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS COMMUNICATIONS
·
2019
·
IF 3.674
Feng Wang,GuoQin Qi,ChuanQi Zhang,HeCheng Ren,Hua Ma,Yu Guo
A series of Na-doped Pt/Al 2 O 3 catalysts with 0.2 wt% of Pt loading and 0–6 wt% Na loading was prepared to investigate the HCHO complete oxidation at room temperature. Powder XRD, BET and XPS were used to characterize the bulk structure and texture of catalysts, as well as the ratio of hydroxyl oxygen to lattice oxygen. A long-term catalyst stability test (50 h on reaction stream) was conducted under severe conditions of a large space velocity of 180,000 mL/h/g, a high HCHO concentration of 80 ppm and dry conditions (relative humidity of 0%). An appropriate amount of doped-Na (2 wt%) contributed to a remarkable improvement of activity and stability of the Na-doped 0.2 wt% Pt/Al 2 O 3 catalyst.
研究领域:
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
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.
研究领域:
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
ChemCatChem
·
2019
·Vol. 11
·期 16
·3903-3912
·
IF 4.495
Nian Lei,Xiaochen Zhao,Baolin Hou,Man Yang,Maoxiang Zhou,Fei Liu,Aiqin Wang,Tao Zhang
Graphical Pt at it, again ! The highest 1,3-PDO yield was obtained over the Pt/WO x /Al 2 O 3 catalyst with a medium domain size of WO x and a Pt/W atomic ratio of 1/4∼1/2, which favored the dispersion of Pt and maximized the number of Pt−WO x interface sites, and consequently promoted the in-situ production of strong Brønsted acid sites. Selective cleavage of secondary C−O bond is an important yet challenging strategy in glycerol valorization, and the product 1,3-propanediol (1,3-PDO) is of great value in polyester industry. Herein, we report a series of Pt/WO x /Al 2 O 3 catalysts for selective hydrogenolysis of glycerol in a fixed-bed reactor and obtain the highest space-time yield of 1,3-PDO (191.7*10 −3 g 1,3-PDO h −1 g −1 cat. ) to date. Both Pt and W have substantial effects on the 1,3-PDO yield with the optimum Pt/W atomic ratio of 1/2∼1/4. Spectroscopy characterizations as well as chemisorption experiments reveal that at the medium domain size of WO x , hydrogen spillover can take place to the greatest extent due to the improved dispersion of Pt and the suitable reducibility of WO x . Dehydration/dehydrogenation tests of 2-butanol suggest that strong Brønsted acid sites are created via hydrogen dissociation at the Pt−WO x interface and spillover to the neighboring oxygen atom. Such in situ formed protons are critical to the selective cleavage of secondary C−O bonds of polyols.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2014
·
IF 5.211
Xiaoyan Liu,Zhongqiang Shan,Kunlei Zhu,Jiangyong Du,Qiwei Tang,Jianhua Tian
Lithium sulfur batteries have brought significant advancement to the current state-of-art battery technologies due to their high theoretical specific energy of 1675 mAh g −1 . However, the rapid capacity degradation, mainly caused by polysulfide dissolution, remains a significant challenge prior to practical applications. In this work, a sulfur cathode modified by bifunctional nafion/γ-Al 2 O 3 membrane has been successfully prepared, which can remarkably immobilize the polysulfides within the unique cathode structure due to its ions selectivity and absorbent capacity. A high initial discharge capacity of 1448.0 mAh g −1 can be achieved at 1C and 788.6 mAh g −1 preserved after 200 cycles, indicating a slow degradation. Furthermore, the coulombic efficiency maintains as high as 97% during cycling. The excellent electrochemical properties can be attributed to the bifunctional and stable membrane which can dramatically reduce the shuttle effect and keep integrated even after charging–discharging for 200 cycles.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）