FUEL
·
2021
·
IF 6.609
Zhanzhi Ge,Yuesong Shen,Sasa Gu
The catalyst for selective catalytic reduction of NO x at high temperatures is significantly demanded by current gas-fired exhaust purification. In this work, the complex oxides composed of two different structures of ZrO 2 -WO 3 and WO 3 /ZrO 2 with zirconium as the main component were prepared for NH 3 -SCR of NO at high temperatures by blending method and equal volume impregnation method, respectively. Combined with XRD, NH 3 -TPD, FE-SEM, BET and in situ DRIFTS characterization, the effects of component optimization of two kinds of ZrO 2 and WO 3 complex oxides on the performance for NH 3 -SCR of NO were mainly studied. The optimal compatibility of ZrO 2 and WO 3 complex oxides was determined, and the corresponding N 2 selectivity and anti-interference ability of water vapor and SO 2 were further investigated. Results showed that the performance of ZrO 2 -WO 3 prepared by blending method for NH 3 -SCR of NO was significantly better than that of WO 3 /ZrO 2 prepared by impregnation method. The ZrO 2 -WO 3 containing 20% WO 3 has the best performance in NH 3 -SCR of NO with NO conversion higher than 90% and N 2 selectivity higher than 90% at 450–650 °C, and the performance was not affected by SO 2 , slightly affected by competitive adsorption of water vapor at 450 °C and not disturbed by water vapor above 500 °C. Further investigation showed that the NH 3 -SCR of NO over the ZrO 2 -WO 3 reaction followed both L-H and E-R mechanisms. Characterization analysis revealed that ZrO 2 -WO 3 has finer microscopic particles, larger specific surface area, higher acid amount and stronger acid strength than WO 3 /ZrO 2 .
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 43
·34451-34455
·
IF 3.84
Yu Liu,Weidong Chi,Hui Liu,Yueyang Su,Liang Zhao
Cubic and tetragonal ZrO2 were synthesized by a sol–gel method using ethanol and glycerol as solvents and ZrOCl2·8H2O as zirconium source. The effect of phase stabilization with amorphous carbon was observed and discussed. The structural evolution, phase transformation and morphological characteristics of powders were investigated by thermogravimetric analysis (TG), differential scanning calorimetric analysis (DSC), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Cubic and tetragonal phase could be generated in this system.
研究领域:
材料科学
·
陶瓷学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Jiaochun Zheng,Mao Deng,Junjing Duan,Jianqi Qi,Zhangyi Huang,Haomin Wang
The nanocrystalline 0.35SiO 2 -0.65ZrO 2 (65 mol% monoclinic ZrO 2 ) glass-ceramic was successfully fabricated via a high-pressure cold sintering process (CSP), displaying remarkable nano hardness and elastic modulus of 12.5 and 154.8 GPa, respectively. We conducted a thorough investigation of the influence of NaOH solution concentration, liquid-to-solid mass ratio, sintering temperature , and pressure on the phase compositions, microstructural evolution , and densification. Notably, excessive NaOH concentration (>0.7 M) results in the transformation of SiO 2 from an amorphous phase to α-quartz, hindering densification. However, below 0.7 M, increasing NaOH concentration enhances the densification processes. Furthermore, higher temperature and pressure contribute to improved densification. It is worth mentioning that there is no grain growth for the ZrO 2 phases during the CSP, indicating that the densification of the nanocrystalline 0.35SiO 2 -0.65ZrO 2 glass-ceramic is primarily governed by the glass phase.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
Nanoscale
·
2021
·Vol. 13
·期 14
·6856-6862
·
IF 7.79
Fan Yang,Chunzheng Wu,Hongbo Yu,Shiwei Wang,Tong Li,Bo Yan,Hongfeng Yin
Nanosized Au catalysts suffer from serious sintering problems during synthesis or catalytic reactions at high temperatures. In this work, we integrate dumbbell-shaped Au–Fe3O4 heterostructures into hollow ZrO2 nanocages to make Au–Fe2O3@ZrO2 yolk–shell nanoreactors with high activity as well as ultra-high sintering resistance for high-temperature CO oxidation. The synthesis starts with the fabrication of a (Au–Fe3O4)@SiO2@ZrO2 core–shell nanostructure with a Au–Fe3O4 dumbbell nanoparticle (DB) core and SiO2/ZrO2 double shells, followed by calcination and the selective removal of the inner SiO2 shell with alkaline solution to obtain Au–Fe2O3@ZrO2 nanoreactors. The retained ZrO2 hollow (outer) shells protect the Au NPs from aggregation at temperatures up to 900 °C and show excellent long-term stability. Compared to Au@ZrO2 yolk–shell nanoreactors, Au–Fe2O3@ZrO2 shows improved activity in CO oxidation due to the active Au–Fe2O3 interface. This strategy can be extended to other yolk–shell nanoreactors with various nanocomposites and for different catalytic reactions.
研究领域:
材料科学
·
催化化学
·
纳米技术
✓ 已验证
DOI
高影响因子
CHEMISTRY LETTERS
·
2022
·Vol. 51
·期 4
·395-398
·
IF 1.715
Zhu Yue,Li Yue,Zhao Shipeng,Jing Ran,Zhang Heqian,Sun Daolai,Sato Satoshi
Hydrogenation of γ-valerolactone (GVL) to form 1,4-pentanediol (1,4-PDO) was performed over Co/ZrO2 catalysts with a Co metal loading of 15 wt. %. The calcination of Co/ZrO2 at high temperatures significantly promoted the catalytic activity irrespective of the decrease in the specific surface area. The 750 °C-calcined Co/ZrO2 with Co2+ species exhibited a high catalytic performance: a GVL conversion of 86.1% with a 1,4-PDO selectivity of 97.2% was achieved at 165 °C under 5 MPa H2 pressure.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Lin Wang,Yongshuai Xie,Dehua Ma,Luyi Zhu,Xinqiang Wang,Xiaotong Jin,Chonghe Xu,Ying Peng,Guanghui Zhang,Dong Xu
As a polycrystalline fiber, continuous zirconia (ZrO 2 ) fiber used at high temperatures will cause grain coarsening and strength degradation due to grain growth. In order to suppress the grain coarsening, zirconium carbide (ZrC) and carbon were introduced into ZrO 2 continuous fibers by pack carburizing , and ZrC/ZrO 2 composite fibers with a radial gradient were subsequently prepared. Due to the pinning effect of ZrC or carbon on the grain boundary, the movement of the grain boundary is limited. The composite fibers obtained in an argon atmosphere at 1400 °C exhibited fine grain, compact micromorphology, and a tensile strength of 784 MPa. The formation process of the composite fiber was accomplished by the interaction of external graphite carbon and internal residual carbon with ZrO 2 . This work provides a simple and economical method for preparing carbide composite fibers.
研究领域:
材料科学
·
高温材料
✓ 已验证
产品关联
DOI
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2019
·
IF 3.834
Yunchao Feng,Miao Zuo,Ting Wang,Wenlong Jia,Xiaoyu Zhao,Xianhai Zeng,Yong Sun,Xing Tang,Tingzhou Lei,Lu Lin
Production of 5-hydroxymethylfurfural (HMF) from glucose with high yield remains a big challenge. Thereinto, assembling catalysts with outstanding performance is the bottleneck at the current stage. In this study, effective catalysts were synthesized by loading SO 4 2− /ZrO 2 (SZ) on a series of H + zeolites to investigate the catalytic dehydration of glucose into HMF. Among all the catalysts applied, 2-SZ-HM-550 (HZSM-5 with Si/Al molar ratios of 80∼150, calcined at 550 °C) gave the yields of HMF 41.32%, 61.14%, 54.67% and 40.71% in 4 applied reaction systems, respectively. Moreover, HMF with desirable yield was obtained while other carbohydrates were dehydrated catalyzed by 2-SZ-HM-550, such as fructose, sucrose, inulin and starch.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
AICHE JOURNAL
·
2018
·Vol. 64
·期 11
·3988-4001
·
IF 3.326
Xiaowen Zhang,Jieling Hong,Helei Liu,Xiao Luo,Wilfred Olson,Paitoon Tontiwachwuthikul,Zhiwu Liang
In this work, the composite catalysts, SO 4 2 /ZrO 2 /γ-Al 2 O 3 (SZA), with different ZrO 2 and γ-Al 2 O 3 mass ratios were prepared and used for the first time for the carbon dioxide (CO 2 )-loaded monoethanolamine (MEA) solvent regeneration process to reduce the heat duty. The regeneration characteristics with five catalysts (three SZA catalysts and two parent catalysts) of a 5 M MEA solution with an initial CO 2 loading of 0.5 mol CO 2 /mol amine at 98°C were investigated in terms of CO 2 desorption performance and compared with those of a blank test. All the catalysts were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, N 2 adsorption–desorption experiment, ammonia temperature programmed desorption, and pyridine-adsorption infrared spectroscopy. The results indicate that the SZA catalysts exhibited superior catalytic activity to the parent catalysts. A possible catalytic mechanism for the CO 2 desorption process over SZA catalyst was proposed. The results reveal that SZA1/1, which possesses the highest joint value of Brφnsted acid sites (BASs) and mesopore surface area (MSA), presented the highest catalytic performance, decreasing the heat duty by 36.9% as compared to the catalyst-free run. The SZA1/1 catalyst shows the best catalytic performance as compared with the reported catalyst for this purpose. Moreover, the SZA catalyst has advantages of low cost, good cyclic stability, easy regeneration and has no effect on the CO 2 absorption performance of MEA. © 2018 American Institute of Chemical Engineers AIChE J , 64: 3988–4001, 2018
研究领域:
化学工程
·
催化材料
·
环境科学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2021
·
IF 3.171
Xiao Zhao,Xuan Shi,Zhongshun Chen,Long Xu,Chengyi Dai,Yazhou Zhang,Xinwen Guo,Dongyuan Yang,Xiaoxun Ma
A series of ZnO-ZrO 2 solid solutions with different Zn contents were synthesized by the urea co-precipitation method, which were coupled with H-ZSM-5 zeolite to form bifunctional catalysts. As a new benzene alkylation reagent, syngas was used instead of methanol to realize the efficient conversion of syngas and benzene into toluene and xylene. A suitable ratio of ZnO-ZrO 2 led to the significant improvement in the catalytic performance, and a suitable amount of acid helped to increase the selectivity of toluene/xylene and reduce the selectivity of the by-products ethylbenzene and C 9 + aromatics. The highest benzene conversion of 89.2% and toluene/xylene selectivity of 88.7% were achieved over 10% ZnO-ZrO 2 &H-ZSM-5 (Si/Al = 23) at a pressure of 3 MPa and a temperature of 450 °C. In addition, the effect of the zeolite framework structure on product distribution was examined. Similar to the molecular dynamics of aromatic hydrocarbons , H-ZSM-5 zeolites comprise 10-membered-ring pores, which are beneficial to the activation of benzene; hence, the conversion of benzene is higher. H-ZSM-35 and H-MOR zeolites exhibited small eight-membered-ring channels, which were not conducive to the passage of benzene; hence, the by-product ethylbenzene exhibits a higher selectivity. The distance between the active centers of the bifunctional catalysts was the main factor affecting the catalytic performance, and the powder mixing method was more conducive to the conversion of syngas and benzene.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of CO2 Utilization
·
2018
·
IF 5.503
Jianyang Wang,Anfeng Zhang,Xiao Jiang,Chunshan Song,Xinwen Guo
Although many researchers have reported CO 2 hydrogenation to various C1 chemicals, it is still challenging to directly and selectively convert CO 2 to C 2 -C 4 hydrocarbons in terms of overcoming the extreme inertness of CO 2 and a high C C coupling barrier. In the present work, we report an efficient integration of methanol-synthesis and the methanol-to-hydrocarbons with the bifunctional catalyst component of In 2 O 3 -ZrO 2 and SAPO-5. These tandem reactions exhibit an excellent relative selectivity of C 2 -C 4 (83%) with a suppressed CH 4 relative selectivity less than 3% at T = 300 °C. A detailed analysis indicates that the partially reduced indium oxide surface (In 2 O 3 -ZrO 2 ) can better activate CO 2 and promote the synthesis of methanol than In 2 O 3 alone, and C C coupling is subsequently manipulated within the confined acidic pores of SAPO-5 according to XRD, H 2 -TPR, CO 2 -TPD, SEM and TEM. Furthermore, the proximity of two components and the content of Si also play an important role in such outstanding selectivity to C 2 -C 4 . Our study paves a new path for the direct synthesis of lower hydrocarbons.
研究领域:
化学工程
·
催化化学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
GREEN CHEMISTRY
·
2017
·Vol. 19
·期 9
·2201-2211
·
IF 9.125
Wenxiu Cao,Wenhao Luo,Hongguang Ge,Yang Su,Aiqin Wang,Tao Zhang
The hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) is a crucial reaction included in many biorefinery schemes for the production of renewable chemicals and fuels. The development of highly stable supported Ru-based catalysts in the polar protic liquid phase under hydrothermal conditions is still a major challenge. Here, we prepared a 0.85 wt% Ru/ZrO2@C catalyst using a new stabilization strategy based on the UiO-66 (Zr-MOF) material. The catalytic performance of this Ru/ZrO2@C in LA-to-GVL was tested and compared with commercial 5 wt% Ru/C at 10 bar H2, 413 K in water and also in high protic aqueous solution (pH = 1). The full conversion of LA and quantitative yield of GVL were achieved with both catalysts. However, the 5 wt% Ru/C showed poor resistance to deactivation already after the first run. ICP, XPS, HRTEM, AC-STEM, TPR and physisorption data showed that quick deactivation of Ru/C was mainly caused by the leaching of ruthenium in addition to the loss of surface area via carbonaceous deposition in micro-pores. In contrast, the self-prepared Ru/ZrO2@C catalyst showed no apparent drop in catalytic performance either in water or in high protic aqueous solution upon multiple recycling, and no leaching of ruthenium was found even under harsh conditions (pH = 1). Remarkably, in the Ru/ZrO2@C catalyst, Ru (probable single-atom) was highly dispersed on nanotetragonal ZrO2 (3.3 nm), embedded in the amorphous carbon, and no apparent Ru nanoclusters were observed even after reactions. TPR results indicated that this excellent stability might be attributed to strong metal–support interaction between Ru and nanotetragonal ZrO2.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS SURVEYS FROM ASIA
·
2020
·Vol. 24
·期 2
·115-122
·
IF 2.194
Gao Meixiang,Jiang Haoxi,Zhang Minhua
This paper has systematically investigated the structures and properties of the ZrO 2 , Nano-SiO 2 and their composition. The catalysts were prepared by impregnation, characterized by N 2 adsorption–desorption, TEM, XRD, Raman, temperature-programmed desorption of NH 3 and CO 2 , FTIR spectroscopy of adsorbed pyridine and CO 2 , and UV–vis spectra. Compared with dry-mixed samples, these catalysts have larger average pore diameter, enabling ZrO 2 to be dispersed more uniformly on the surface of Nano-SiO 2 . With the Zr–O–Si bonds, ZrO 2 could interact intensely with Nano-SiO 2 . The catalyst prepared shows the best performance, with the selectivity of 93.18% and conversion of 58.52%. The preparation methods have a significant influence on the interaction between ZrO 2 and Nano-SiO 2, which then affects the acid–basic properties. This paper finds that weak acid–basic sites with moderate-intensity are more suitable for ethanol conversion to BD, with the amount of acid and basic sites as close as possible.
研究领域:
催化化学
·
材料科学
✓ 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）