ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2020
·Vol. 27
·期 24
·30243-30253
·
IF 3.056
Xu Wenqing,Gao Lei,Yang Yang,Zhu Tingyu,Qi Guisheng
The deposition of NH 4 HSO 4 on catalysts is one of the key issues for selective catalytic reduction of NO x . In this study, NH 4 HSO 4 was preloaded on catalysts, and the effects of MoO 3 and CeO 2 doping on the decomposition and reactivity of NH 4 HSO 4 on V 2 O 5 /TiO 2 catalysts are studied. The results show that the introduction of MoO 3 and CeO 2 significantly promoted NO x conversion on the V 2 O 5 /TiO 2 catalysts. Doping with MoO 3 could effectively enhance the S and H 2 O resistance of the catalysts. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis indicate that it is the strong chemical interactions between NH 4 HSO 4 and the catalysts that are adverse to the decomposition of NH 4 HSO 4 . However, doping with MoO 3 apparently inhibits these interactions, which significantly decrease the decomposition temperature of NH 4 HSO 4 . In situ FTIR experiments show that the NH 4 + in preloaded NH 4 HSO 4 could react with gaseous NO on catalysts, and doping with MoO 3 could facilitate the reaction rate.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 31
·25877-25881
·
IF 3.289
Ling Li,Mingkun Wang,Ning Cui,Yuedi Ding,Qingling Feng,Wenming Zhang,Xiaowei Li
Incorporation of nanophase ceria into the cathode catalyst Pt/C was used as alternative cathode catalysts for the oxygen reduction reaction in an air-cathode single-chamber microbial fuel cell (SCMFC) for the first time. Electrochemical results reveal that the ceria doped Pt/C catalysts exhibited a higher catalytic performance than the pure Pt/C catalyst. The highest voltage of 580 mV and the maximum power density of 840 ± 24 mW m−2 were achieved from the 3 wt% CeO2 doped Pt/C cathode, which was larger than that of the pure Pt/C cathode.
研究领域:
环境科学
·
电化学
·
能源材料
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2024
·
IF 3.7
Yutong Pan,Pengju Gao,Shixiong Tang,Xiaoyu Han,Ziwen Hao,Jiyi Chen,Zhenmei Zhang,Heng Zhang,Xiaohui Zi,Maoshuai Li,Shiwei Wang,Yue Wang,Xinbin Ma
This work synthesized a series of Ni/CeO 2 /Al 2 O 3 catalysts with varying CeO 2 doping amounts to enhance low-temperature CO 2 methanation. The introduction of CeO 2 weakens the interaction between Ni and Al 2 O 3 , leading to the formation of Ni-CeO 2 active sites. This results in a high dispersion of Ni and CeO 2 , improved catalyst reducibility, increased number of active sites, and enhanced the CO 2 methanation. This work further investigated the impact of WHSV and catalyst stacking configuration to enhance the reaction. When the catalyst is stacked into three segments with a temperature gradient of 330 °C, 300 °C, and 250 °C under WHSV=9000 ml·h –1 ·(g cat) –1 , the CO 2 conversion significantly increases to 95%, which is remarkably close to the thermodynamic equilibrium (96%).
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
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Xiaodong Wei,Guoliang Hou,Yulong An,Pan Yang,Xiaoqin Zhao,Huidi Zhou,Jianmin Chen
6-8 wt% yttria-stabilized zirconia (YSZ) has been widely employed as thermal barrier coating (TBC) to protect the high-temperature components of aero-engine and gas-turbine. However, the phase transition and sintering densification at high temperature seriously limit its application above 1200 °C. On account of this, CeO 2 and Sc 2 O 3 were doped into the YSZ by solid-state reaction sintering method in this paper. The effects of doping on the crystal structure, phase transition behavior and sintering resistance were investigated on the basis of XRD, Raman and FESEM , and the evolution of thermal properties of the ceramics was also analyzed. The results indicated that doped CeO 2 increases the cell volume and tetragonal degree, but doped Sc 2 O 3 was opposite. Co-doping caused not only significant difference in atomic mass and radius but also the formation of a large number of oxygen vacancies in the ceramics. Therefore, CeScYSZ showed the lowest thermal conductivity (1.53 W‧m −1 ‧K −1 ), which was about 23% lower than that of YSZ (2.00 W‧m −1 ‧K −1 ). More importantly, the oxygen vacancy also effectively stabilized the octet lattice, while the increase of lattice energy caused by Sc-O bond made it difficult for ions to misplace, which finally well prevented the transformation from t phase to m phase. There was no detrimental m -ZrO 2 phase formation in the CeScYSZ after 120 h at 1500 °C. Besides, Co-doping could simultaneously overcome the poor sintering resistance caused by single CeO 2 doping and the lower thermal expansion coefficient caused by single Sc 2 O 3 doping, thus the CeScYSZ should be an ideal long-acting thermal protection material at higher temperatures.
研究领域:
材料科学
·
高温材料
·
陶瓷材料
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Express
·
2024
·Vol. 11
·期 7
·075101
·
IF 1.8
Lina Zhan,Yao Zhang,Xuan Zhang,Yuzhibiao Xia,Yao Liu
The densification mechanism of CeO2 doped Si3N4 ceramics during spark plasma sintering (SPS) was investigated. The sintering process was observed to undergo significant densification at the intermediate stage of sintering (1435 °C–1816 °C), and the density and grain size of CeO2 doped Si3N4 ceramic were found to be greater than those of pure Si3N4 ceramic under the same sintering conditions. To determine the densification mechanism, a creep model was utilized to determine the densification mechanism which could be interpreted based on the values of the stress exponent (n) and the apparent activation energy (Qd). The results revealed that the Qd of pure Si3N4 (381.15 kJ mol−1) is higher than that of Si3N4-CeO2 powder (265.61 kJ mol−1). Moreover, the stress exponent n of Si3N4-CeO2 powder (1.12–1.33) was higher than that of pure Si3N4 powder (1.00–1.18). This can be attributed to the fact that the addition of CeO2 resulted in the formation of a liquid phase at the grain boundary which leading to a shift in the controlling mechanism from grain boundary diffusion to grain boundary sliding.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
Coatings
·
2023
·Vol. 13
·期 3
·534
·
IF 3.4
Ke An,Gang Li,Tingting Fan,Feng Huang,Wenlin Wang,Jing Wang
AgNbO3-based ceramics have been widely studied as ideal lead-free materials. Herein, AgNbO3:xCeO2(x= 0, 1, 2 mol%) ceramics were successfully prepared by the conventional solid-state reaction method. The optimization of energy storage properties is ascribed to the enhanced antiferroelectric (AFE) stability and the increased breakdown strength (Eb). The reduction of the tolerance factor leads to the enhancement of AFE stability. In addition, the enhancement ofEbis due to the increase of actual density, which is achieved through the regulation of CeO2amount and grinding procedure in the experimental process. A high recoverable energy density (Wrec) of 5.04 J/cm3and an energy efficiency (η) of 46.2% were achieved in AgNbO3:0.01CeO2ceramics under an applied electric field up to 390 kV/cm. A higherηof 55.4% was obtained in AgNbO3:0.02CeO2components. This research provides guidance for finding ceramic materials with comprehensive energy storage properties.Keywords:antiferroelectric materials;energy storage performance;AgNbO3;breakdown strength;grain size heterogeneity
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS RESEARCH
·
2020
·Vol. 35
·期 3
·242-251
·
IF 2.502
Ying Zhou,Guoyou Gan,Zhenhua Ge,Peng Song,Jing Feng
SmTaO4 ceramics have excellent high-temperature phase stabilities and mechanical properties and show great potential for use as next-generation thermal barrier coating (TBC) materials. CeO2–SmTaO4 ceramics are prepared via high-temperature solid–state reaction. It retains a single monoclinic phase structure. Ce4+ was reduced to Ce3+ by high-temperature deoxidation, and the Ce3+ ions substitute for an equal number of Sm3+ ions. The CeO2–SmTaO4 ceramics had lower thermal conductivities [1.09–2.75 W/(m K)] than yttria-stabilized zirconia (YSZ) [2.1–2.7 W/(m K)] at 100–800 °C, which decreased dramatically with increasing temperature. SmTaO4 doped with 2% CeO2 had lower thermal conductivity [1.09 W/(m K), 800 °C] than SmTaO4 [1.42 W/(m K), 800 °C] and 2% ZrO2-doped SmTaO4 ceramics [1.22 W/(m K), 800 °C]. The low thermal conductivity is attributed to Ce3+ substitution for an equal number of Sm3+ ions, and because Ce3+ ions are the strongest phonon scattering centers, they can decrease the phonon mean free path effectively. The thermal expansion coefficient of 8% CeO2–SmTaO4 ceramics is approximately 10.3 × 10−6 K−1 at 1200 °C, which is slightly higher than that of both YSZ (10.0 × 10−6 K−1) and SmTaO4 (9.58 × 10−6 K−1). The outstanding thermophysical properties indicate that CeO2–SmTaO4 ceramics are potential TBC materials.
研究领域:
材料科学
·
无机非金属材料
·
热障涂层技术
·
高温功能材料
·
固态化学
·
热物理性能
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）