FUEL
·
2024
·
IF 6.7
Qitong Xue,Jiaying Xing,Jianjun Chen,Jinxing Mi,Jianqiang Shi,Yao Wang,Junhua Li,Zhiming Liu
V 2 O 5 /TiO 2 has been wide used in the selective catalytic reduction of NO x by NH 3 (NH 3 -SCR). However, the poisoning mechanism of thallium (Tl) on the catalytic performance of commercial V 2 O 5 /TiO 2 catalyst has remained unclear. Herein, we have systematically investigated the poisoning effect of Tl based on the different characterizations and DFT calculations. It was found that the strong interaction between V and Tl exists, resulting in the transformation of V from monomeric VO x to polymeric and crystalline VO x , the formation of V-O-Tl species, a decrease in the active V 5+ sites, and the inhibition of the adsorption and activation of NH 3 on both Brønsted and Lewis acid sites. Mechanistic studies further confirmed that inactive nitrate intermediate species gradually accumulated over V 2 O 5 /TiO 2 catalyst surface due to the presence of Tl. A combination of factors ultimately led to the deactivation of the V 2 O 5 /TiO 2 catalyst. This study unveils the poisoning mechanism of Tl on V-based catalysts and shed light on the design of Tl-tolerant NH 3 -SCR catalysts.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
Minghu Zhao,Junyi Chen,Fei Wu,Yungang Wang,Kai Chen,Chao Xiong,Rongshu Zhu
Rationally designing catalysts suitable for flue gas purification at low temperatures and unraveling the anti-poisoning mechanism at the atomic level remain challenges. Here, a highly dispersed Ni-doped MnO x catalyst (Ni 0.1 Mn 0.9 O x ) was constructed and applied for selective catalytic reduction (SCR) of nitrogen oxides (NO x ). The long-term stability of Ni 0.1 Mn 0.9 O x is up to 80% (180 ℃) after 18 h under SO 2 and H 2 O conditions. This is due to the fact that the highly dispersed Ni atoms enhance the redox and surface acidity of MnO x , and modulate the electronic structure of the active Mn sites. The denitrification reaction on Ni 0.1 Mn 0.9 O x mainly follows the Eley-Rideal mechanism. The anti-poisoning mechanism is that the introduction of Ni weakens the electron transfer between the Mn site and SO 2 , thereby inhibiting the adsorption of SO 2 . In particular, the H 2 O adsorbed on the Ni sites is decomposed to replenish the depleted Brønsted acid sites, which facilitates the adsorption of NH 3 . However, an excess of H 2 O can have an inhibitory effect. In addition, the mesoporous structure may increase the mass transfer rate and reduce the accumulation of harmful substances. This study provides viable insights for the design of SCR catalysts with excellent anti-poisoning ability.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2025
·
IF 9.5
Meiting Guo,Zhishan Li,Lang Tang,Jingwei Li,Zehua Wang,Bo Wang,Zongping Shao,San Ping Jiang,Zhongwei Yue
Due to their low activation energy and high mobility of proton transfer, protonic ceramic cells (PCCs), including protonic ceramic fuel cells (PCFCs) and protonic ceramic electrolysis cells (PCECs), working at relatively low temperatures (400–700 °C) have gained increasing attention as promising and highly efficient energy conversion and storage technologies to replace the oxide ion-conducting, high-temperature solid oxide cells (SOCs). However, similar to SOCs, Fe–Cr based alloys are also commonly used as metallic interconnects in PCCs. Thus, the practical applicability of Ba-containing proton conducting electrolytes in PCCs is fundamentally related to their tolerance and resistance towards the deposition and poisoning of the volatile chromium species from the Fe–Cr based interconnect. This study focuses on the interaction between the Cr species and the most widely used proton conducting electrolyte BaZr0.1Ce0.7Y0.1Yb0.1O3−δ (BZCYYb1711) within a temperature range from 400 °C to 700 °C. Results indicated that barium oxide and the BZCYYb1711 powder reacted with the Cr2O3 powder at 250 °C and 400 °C, respectively, while the deposition of Cr species on the BZCYYb1711 electrolyte surface occurred at temperatures as low as 500 °C. Ba segregated from the BZCYYb1711 electrolyte and reacted with gaseous Cr species, forming BaCrO4 and causing a significant depreciation in Ba content in the electrolyte. The Cr species also diffused into the inner layer of BZCYYb1711, leading to the segregation of CeO2 and degrading the conductivity of the electrolyte. This study demonstrates that the deposition and poisoning of the Cr species from the Fe–Cr based metallic interconnect are serious issues for the practical and long-term applicability of Ba-containing protonic ceramic materials in PCCs.
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Peng Lu,Lyumeng Ye,Xianhui Yan,Jianhang Huang,Zhixiong Tang,Dongyao Chen,Chaoping Cen
It is challenging for catalytic oxidation of volatile organic compounds (VOCs) due to the existence of HCl in municipal solid waste incineration flue gases. A thorough probe into the deactivation mechanism is imperative but still lacking. Herein, the poisoning effect of gaseous HCl on a Ru-based catalyst for toluene catalytic oxidation was investigated. Toluene conversion and CO 2 selectivity decreased dramatically from 89.3 % and 93.8 % to 15.0 % and 8.0 %, respectively at 250 °C under HCl atmosphere. HCl led to a reduction of low-temperature redox properties, as well as a decrease of BET surface area, surface oxygen content and mobility, resulting in a loss of catalytic activity. HCl combined with active Ru and Mn, thereby restricting the electron transfer between Ru 4+ and Mn 2+ . Moreover, HCl could be oxidized by active oxygen species to form Cl• radical, which subsequently reacted with toluene oxidation intermediates, resulting in the generation of chlorinated compounds, such as chlorobenzene, dichlorobenzene, carbon tetrachloride, and benzyl chloride. These harmful chlorinated compounds predominantly deposited on catalyst surface. The protective role of H 2 O against HCl poisoning was mainly attributed to the competitive adsorption between H 2 O and Cl ions, the washing effect, and the promoting of intermediates oxidation and oxygen activation. It is noteworthy that during toluene oxidation in the presence of HCl + H 2 O, a detectable level of 0.048 ng I-TEQ/Nm 3 PCDD/Fs was observed in the off-gas.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Zulfiqar Ali,Yang-wen Wu,Yue Wu,Zulqarnain Arain,Ming-xin Xu,Qiang Lu,Heping Ma,Huan-yu Zhao
Lead (Pb) species are inescapable constituents of the flue gas from coal-fired power plants and other thermal devices, which can cause impeding effects on the selective catalytic reduction (SCR) reactions. Here, the poisoning effects of Pb on the V 2 O 5 -MoO 3 /TiO 2 type SCR catalyst were examined. The poisoned catalysts were prepared by the solid diffusion and incipient wetness impregnation (IWI) methods. The catalytic activity tests indicated that the Pb-doped catalyst prepared by the IWI method suffered a considerable drop in catalytic activity, while a slender influence was observed on the Pb-loaded catalysts prepared by solid diffusion method. Comprehensive characterizations and density functional theory (DFT) calculations were performed on the fresh and poisoned catalysts prepared by the IWI method to unveil the deactivation mechanism. The results showed that Pb species covered the active sites (V species) on the catalyst surface, resulted in the decrease in chemisorbed oxygen, hence reducing the surface acidities. The decrease in reducibility of the catalyst was an important factor for poisoning of the catalyst. Moreover, Pb species reacted with MoO 3 to form PbMoO 4 which agglomerated on the catalyst surface to further deactivate the catalyst.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2020
·
IF 7.489
Xiaoqiang Wang,Yue Liu,Zhongbiao Wu
Low-medium temperature NH 3 -SCR technology has been applied for years in municipal solid wastes incineration (MSWI) to control the emissions of nitrogen oxides . Unlike coal-fired flue gases , the tail gas from MSWI contains high levels of heavy metals in fly ash, especially the zinc species, which may harm SCR catalysts. As such, in this paper, the deactivation mechanism of different zinc species (ZnO, ZnSO 4 and ZnCl 2 ) on the Sb-CeZr 2 O x catalysts and the co-effects of zinc species and gas-phase pollutants (including SO 2 and HCl) were investigated. The experimental results indicated that the deactivation rate of various poisoning zinc species was in the order of ZnCl 2 > ZnSO 4 > ZnO. Moreover, the interactions between zinc and antimony species would disrupt the structure of the Sb-Ce mixed oxides to decrease the redox ability, consequently suppressing the ammonia activation and NO adsorption. Furthermore, such damaging effects on catalyst structures would promote the formation of bulk-like sulfate species in the presence of SO 2 , resulting in a decreased mobility of surface oxygen species, which significantly decrease the sulfur resistance. However, the presence of HCl did not show an evident co-effect on the Zn poisoned sample owing to the limited coverage of the chlorine deposition.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）