CATALYSIS LETTERS
·
2020
·Vol. 150
·期 7
·2045-2055
·
IF 2.482
Li Chaoqun,Yang Yang,Ren Wei,Wang Jian,Zhu Tingyu,Xu Wenqing
Abstract CO is toxic and detrimental to human beings and the atmosphere. The presence of CO has become one of the important indicators for evaluating ambient air quality. Iron and steel sintering generate large amounts of flue gas emissions containing approximately 1% CO, which has become an important factor restricting the improvement of air quality in steel cities. The catalytic oxidation method is the simplest and most effective method for CO emission control. In this work, a series of Cu x Ce y /TiO 2 catalysts with different Ce doping levels were prepared by a one-step impregnation method and subsequently tested for catalytic CO oxidation. The Cu 0.5 Ce 0.5 /TiO 2 sample has the best catalytic activity under the conditions of 1% CO and 10% H 2 O. The catalysts were next characterized by XRD, BET, TEM, H 2 -TPR, XPS and in-situ DRIFTS methods. The characterization results show that Ce doping promotes the dispersion of copper species on the catalyst surface and improve the redox performance of the catalyst. The results of in-situ experiments showed that both Cu/TiO 2 and Cu 0.5 Ce 0.5 /TiO 2 catalysts followed Mars and van Krevelen mechanism, and Ce doping enhanced the adsorption and activation of oxygen, thus improving the low-temperature reaction activity of the catalysts. Graphic Abstract
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
ChemistrySelect
·
2025
·Vol. 10
·期 12
·e202500499
·
IF 2
Tianzhu Shao,Qi Wang,Jiahao Wei,Gonggang Sun,Xinbao Li
Graphical The study focuses on the synthesis of SCR catalysts with high activity and excellent alkali resistance. The redox performance and surface acidity of VWTi are enhanced and the atomic valencies is optimized through the doping of Ce and Bi. Therefore, the catalytic activity of the catalyst is significantly enhanced and excellent catalytic activity is maintained even after KCl poisoning. Ce-doped V 2 O 5 -WO 3 /TiO 2 (CeVWTi) and its subsequent modifications have been recognized as effective catalysts for the selective catalytic reduction of NO. Herein, CeVWTi catalysts doped with varying amounts of bismuth sulfate (Bi 2 (SO 4 ) 3 ) were synthesized and evaluated for their activity and alkali resistance. These catalysts were characterized using XPS, BET, SEM, H 2 -TPR, NH 3 -TPD, and XRD techniques. The optimal doping level of Bi 2 (SO 4 ) 3 was 1 wt.%. The NO conversion rate of the catalyst co-doped with Ce and Bi was 71.6% under the reaction conditions of 300 °C, gas hour space velocity (GHSV) = 200,000 h −1 with a gas composition of 550 ppm NO, 550 ppm NH 3 , 5.6% O 2 , and N 2 as the balance. The NO conversion efficiency of the Bi 0.01 CeVWTi catalyst was maintained at 90.7% after the addition of 1 wt.% KCl poisoning under the reaction conditions of 350 °C, GHSV = 200,000 h −1 , 550 ppm NO, 550 ppm NH 3 , 5.6% O 2 , and N 2 as the balance. Characterization showed that, despite the reduction in the specific surface area of the catalyst and some acidic sites due to Bi doping, the redox performance of Bi 0.01 CeVWTi was significantly enhanced. The excellent redox performance was maintained even after KCl poisoning.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
ACS Catalysis
·
2015
·
IF 9.312
Kunfeng Zhao,Hailian Tang,Botao Qiao,Lin Li,Junhu Wang
Au/γ-Fe2O3 and Au/α-Fe2O3 catalysts with identical size of Au nanoparticles, chemical state of Au species, and amount of surface OH– group were prepared. The Au/γ-Fe2O3 catalyst exhibited exceptionally high activity, regardless of the heat treatments. The CO-TPR, sequential pulse reaction, and in situ Raman spectra demonstrate that the much higher activity of Au/γ-Fe2O3 originated from its higher redox property at low temperature. Systematic study shows that this higher-redox-property-based higher activity could be extended to γ-Fe2O3-supported Pt-group metals and to other reactions that follow Mars–Van Krevelen mechanism. This finding may provide a new avenue for catalyst improvement or development by choosing the suitable crystal phase of the oxide support.
研究领域:
催化化学
·
材料科学
·
表面科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Zhipeng Yang,Siru Lu,Tianyu Wu,Hong Yao,Changan Zhou,Chao Wang,Kui Ma,Lei Song,Hairong Yue
Acid sites and redox sites with high thermal stability are crucial for the NH 3 -SCR catalyst for diesel vehicles. The surface acidity of FeTi catalysts is improved by modified with the solid acid of PO 4 3- or WO 3 . The acid-modified FeTi catalysts show superior NH 3 -SCR activity hydrothermal stability with a wide temperature window. The introduction of acid groups not only provides a large number of Brønsted acid sites but also promotes high dispersion of the active species of redox sites due to the formation of the structure P-O-Fe/W-O-Fe. The P-O-Fe/W-O-Fe structure can also improve the redox properties of the FeTi catalysts and inhibit the phase transformation of the TiO 2 support during high-temperature hydrothermal process. The reaction kinetics indicate that the reaction rate is primarily related to the concentration of NO. The mechanistic study indicates that the catalytic reaction is primarily governed by the Eley-Rideal mechanism.
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
Materials Research Express
·
2021
·Vol. 8
·期 4
·045509
·
IF 1.62
Ruian Wu,Jiang Jin,Kun Li,Lei Zhao,Hua Zhang
The FeaTibOx catalyst was loaded into the pores of porous ceramic using impregnation method for removing nitrogen oxides with selective catalytic reduction (SCR) technology. The catalytic performance over FeaTibOx catalyst was studied in detail. The Fe6Ti1Ox catalyst displayed more than 95% NOx conversion within the range of 280 °C–400 °C, and still maintained 97% NOx conversion when 300 ppm SO2 and 10 vol.% water vapor were introduced at the testing temperature of 300 °C. The influence factors (including filtration velocity, NH3/NO mole ratio and oxygen concentration) for NOx conversion over Fe6Ti1Ox catalyst were also studied. The suitable NH3/NO mole ratio and oxygen concentration was 0.9 and 6%, respectively. The XRD, N2-BET, H2-TPR, NH3-TPD and XPS were employed to investigate physicochemical property of the FeaTibOx catalyst. The results illustrated that Fe6Ti1Ox catalyst has hematite Fe2O3 and TiO2 structure, better redox properties and stronger surface acid.
研究领域:
环境科学
·
催化材料
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Huixian Zhou,Hui Zhong,Yiqing Zeng,Yutang Kang,Bin Chen,Shuanglu Ma,Yifan Li,Yu Zhang,Shasha Feng,Zhaoxiang Zhong,Weihong Xing
The strategy of constructing catalytic membrane has a significant influence on its structure and performance. In this work, Co 3 O 4 -C x @SiO 2 nanofiber membranes (NFMs) were fabricated by an in-situ growth–pyrolysis–oxidation strategy. The Co 3 O 4 -C x catalyst derived from ZIF-67 was wrapped around nanofibers, which helps to maintain a stable membrane structure, then suppressing the reduction of gas permeability. Among the Co 3 O 4 -C x catalyst, the carbon skeleton can prevent the agglomeration of Co 3 O 4 nanoparticles, obtaining an ultra-fine Co 3 O 4 nanoparticles with high dispersibility, redox property and surface area. The obtained Co 3 O 4 -C 300 @SiO 2 NFM exhibits outstanding ammonia selective catalytic reduction (NH 3 -SCR) denitrification activity (T 90 = 225 °C at a GHSV of 77,000 h −1 ). The effect of catalyst loading on PM 2.5 filtration performance of SiO 2 NFM was also tested. Co 3 O 4 -C 300 @SiO 2 NFM has higher filtration efficiency (99.99%) than SiO 2 NFM at a lower pressure drop of 58 Pa, which suggests that catalyst loading via our method can improve the filtration performance of SiO 2 NFM. This work might provide a universal strategy for the design and preparation of highly efficient catalytic membrane.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2020
·Vol. 10
·期 23
·8086-8093
·
IF 5.721
Haoxi Jiang,Debin Kong,Ying Niu,Sheng Wang
MnO2–CoOX catalysts with different Mn/Co ratios were prepared using polyvinyl pyrrolidone (PVP) as an assistant to control the morphology and exposed crystal faces of composite oxides. The physicochemical properties of the catalysts were systematically characterized and the catalytic activity of NH3-SCR and resistance to SO2/H2O were investigated. It was found that the NO conversion over Mn–Co-0.2-PVP was apparently higher compared with that over Mn–Co-X-PVP (X = 0.9, 0.8, 0.6, and 0.4). This can be interpreted in terms of exposed crystal surface (110) and enhanced adsorption of NH3/NO, and better redox performance resulting from higher Co3+/Co2+ ratio. Furthermore, different PVP and HAc additives have different H2O and SO2 resistance. Mn–Co-0.2-PVP showed good resistance to H2O and SO2 poisoning owing to having more low-temperature (∼200 °C) NO adsorption sites, which are beneficial to promote the de-NOX reaction and less affected by SO2.
研究领域:
环境科学
·
催化材料
✓ 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）