PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2017
·Vol. 19
·期 7
·5333-5342
·
IF 4.123
Shu-xian Wang,Rui-tang Guo,Wei-guo Pan,Ming-yuan Li,Peng Sun,Shu-ming Liu,Shuai-wei Liu,Xiao Sun,Jian Liu
It was well recognized that Pb had a poisoning effect on a SCR catalyst. In this study, the deactivation mechanism of Pb on the Ce/TiO2 catalyst was investigated based on the characterization results of TPD and in situ DRIFT studies. It was found that the addition of Pb on the Ce/TiO2 catalyst not only inhibited the adsorption and activation of NH3 species, but also led to the decrease of the activity of adsorbed NH3 species in the SCR reaction. The adsorption of NOx species and the oxidation of NO by O2 over the Ce/TiO2 catalyst were also suppressed by the addition of Pb, while the reactivity of adsorbed NO2 species did not decrease. Moreover, the results revealed that the NH3-SCR reaction over the Ce/TiO2 catalyst followed both the E–R and L–H mechanisms, while the NH3-SCR reaction over Ce/TiO2-Pb was mainly controlled by the L–H mechanism. The contributions of the L–H mechanism to the SCR reactions over Ce/TiO2 and Ce/TiO2-Pb decreased with increasing reaction temperature. The deactivation of Ce/TiO2-Pb was mainly attributed to the suppressed NH3 adsorption and activation, accompanied by the inhibited NO oxidation and the decrease of Brønsted acid sites.
研究领域:
环境催化
·
大气污染控制
·
材料化学
·
表面科学
·
物理化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 86
·82707-82715
·
IF 3.289
Wei Li,Rui-tang Guo,Shu-xian Wang,Wei-guo Pan,Qi-lin Chen,Ming-yuan Li,Peng Sun,Shu-ming Liu
A series of Mn/CeSiOx catalysts were prepared by the wet impregnation method and used for selective catalytic reduction of NO with NH3. As can be seen from the experimental results, the Mn/CeSiOx catalyst with a Ce/Si molar ratio of 2/1 showed excellent low-temperature SCR activity, high N2 selectivity and excellent SO2 and H2O tolerance. The relationship between the CeSiOx support and the SCR performance of Mn/CeSiOx (2 : 1) catalyst was investigated based on the characterization results of N2 adsorption, XRD, XPS, H2-TPR, NH3-TPD and in situ DRIFT. The strong interaction between Ce and Si resulted in the good dispersion of Mn species on the support; correspondingly, the redox ability and NH3 adsorption capacity were greatly enhanced. The results of in situ DRIFT study revealed that the NH3-SCR reactions over Mn/CeO2 and Mn/CeSiOx (2 : 1) mainly obeyed both the E–R mechanism and the L–H mechanism. Furthermore, the formation of more Mn4+ and chemisorbed oxygen greatly facilitates the oxidation of NO to NO2, as a result, promoting the low-temperature SCR performance of Mn/CeSiOx (2 : 1).
研究领域:
催化
·
环境科学
·
化工
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Siqian Zhang,Cheng Zhang,Qiang Wang,Wha-Seung Ahn
A series of ZSM-5 catalysts were synthesized using fly ash from power plants and red mud from aluminum production in different weight ratios. The ZSM-5 was subsequently coimpregnated with Co and Mn and tested for the low-temperature selective catalytic reduction of NOx by NH3 (NH3-SCR). These catalysts were characterized by XRD, N2-adsorption isotherms, SEM, XPS, and H2-TPR. Among all the prepared catalysts, 5 wt % Co 10 wt % Mn/ZSM-5 had shown the best catalytic activity, with 98.8% conversion of NOx and 90.7% selectivity toward N2 at 150 °C. This is comparable to the performance of a similar ZSM-5 catalyst prepared using chemical reagents. The high ratio of Mn4+/(Mn4+ + Mn3+ + Mn2+) in the catalyst improved the NOx conversion, whereas the moderate redox property imparted by Co3+ led to high N2 selectivity. This catalyst also showed strong resistance against poisoning in 100 ppm SO2 and 5% H2O. This work demonstrates that effective NOx removal treatment with high N2 selectivity and sufficient stability for either cement plants or incinerators can be achieved by using a porous catalyst/support material produced from industrial solid wastes.
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
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Bingke Xie,Dongyun Chen,Najun Li,Qingfeng Xu,Hua Li,Jianmei Lu
Nitrogen oxide (NOx) removal has long been a subject that has motivated researchers to develop a diverse range of techniques, including physical adsorption, biofiltration, low temperature plasma, selective catalytic reduction, and photocatalytic oxidation. In this work, Cs 3 Bi 2 Br 9 lead-free perovskite was synthesized via in-situ growth on a 3D flower-like g-C 3 N 4 microsphere, which uses a series of Cs 3 Bi 2 Br 9 /g-C 3 N 4 (labeled as X% CBB/CN, where X = 5, 10, 20, 30, and 50) heterojunctions for the photocatalytic removal of NOx. The efficiency of NO removal was enhanced considerably, compared with that of the pristine elements, when irradiated with a 300 W Xe lamp with the concentration of NO at the ppb level. The results of photocurrent measurements and electrochemical impedance spectroscopy are consistent with the results of the NO removal test. Electron spin resonance results verified that ⋅OH and ⋅O 2 − are formed under visible light irradiation. We report the detailed mechanism for the photocatalytic process of NO removal by CBB/CN heterojunctions and provide insights into the potential applications of lead-free perovskite-based heterostructures in the field of photocatalysis.
研究领域:
材料科学
·
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCES IN ATMOSPHERIC SCIENCES
·
2021
·Vol. 38
·期 7
·1238-1251
·
IF 3.158
Zhang Hailiang,Xu Yongfu,Jia Long,Xu Min
Acetaldehyde is one of the important VOC species of O 3 precursors in the atmospheric environment. The influences of relative humidity (RH) and initial VOC/NO x ratio ( R CN ) on the formation of O 3 are studied in smog chamber experiments, and the MCM v3.3.1 mechanism of acetaldehyde is modified based on the experimental results. In low-RH conditions (RH = 11.6%±1.1%), the O 3 concentration at 6 h increases first and then decreases with the increase of R CN , and the R CN at the inflection point of O 3 concentrations is 3.2. In high-RH experiments (RH = 78.8%±1.0%), variation of the O 3 concentration at 6 h with R CN is similar to that in low-RH experiments, but the R CN at the inflection point is 2.8. RH has no significant effect on the O 3 concentrations under low R CN (< 3), whereas it has a negative effect under high R CN (> 3). Compared with the experimental results, original MCM v3.3.1 greatly underestimates the O 3 concentrations. Addition of both the photolysis process of peroxyacetyl nitrate and the photolysis process of HNO 3 on the reactor surface into the original MCM can reduce the difference between the simulated O 3 concentrations and the experimental results at 6 h from 24%−35% and 17%−49% to 6%−26% and 10%−42% under low- and high-RH conditions, respectively. The maximum incremental reactivity (MIR) of acetaldehyde simulated with the modified MCM is 4.0 ppb ppb −1 without considering the effect of other VOCs.
研究领域:
大气科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL PAPERS
·
2017
·Vol. 72
·期 1
·51-56
·
IF 1.258
Wei Mengyi,Qian Chao,Chen Xinzhi
Based on the recycling of NO
x
, the Cu(I)- and HNO 3 -catalyzed oxidation of 2-chloro-4-(methylsulfonyl)toluene to 2-chloro-4-(methylsulfonyl)benzoic acid has been developed with an excellent yield of 84.2% and a purity of 99.7%. The optimized reaction conditions (160 °C, oxygen pressure 1.5 MPa, HNO 3 concentration 25 wt%, HNO 3 : substrate 0.5:1) use 1.0 mol% CuI as catalyst. The dosage of HNO 3 in the new process is only 25% of the stoichiometric amount and 12.5% of the amount of the traditional process. The NO
x
emission is 5% amount of the traditional process. The oxidation of several additional toluene derivatives with comparable yields demonstrates the generality to these reaction conditions.
研究领域:
化学
·
环境科学
✓ 已验证
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2021
·
IF 6.141
Heyang Si,Mengyuan Zhou,Yongle Fang,Jianhui He,Lu Yang,Fazhou Wang
The application of titanium dioxide (TiO 2 ) photocatalyst in concrete is considered a promising method to effective remove nitrogen oxide (NOx) pollutants. However, the influences of application ways on photocatalytic efficiency and catalyst durability should be concerned in detail for its large-scale application. This paper compared the photocatalytic NOx degradation efficiency and durability of conventional TiO 2 powder dispersed in cement mortar (TPC), TiO 2 supported aggregates mounted on cement mortar surface (TAS) and TiO 2 supported aggregates dispersed in cement mortar (TAD), with considering different environmental factors effects such as gas flow rate, NO initial concentration and relative humidity. The photocatalytic efficiency results show that the NOx removal efficiency of TAS is about 1.5 and 1.1 times higher than that of TPC and TAD, respectively, corresponding to the utilization efficiency of TiO 2 photocatalysts in TAS is ca. 10 and 16 times higher than in TPC and TAD, respectively. The surface abrasion test suggests that TAS has relatively low photocatalytic efficiency compared with TAD after polishing the sample surface by more than 2 mm, which depends on the mounted thickness of TiO 2 supported aggregates. The findings in this work can provide the basis for the application ways of TiO 2 supported aggregates in concrete by considering its photocatalytic efficiency, economic efficiency and catalytic durability.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2019
·
IF 7.149
Fei Wang,Zhibo Xie,Jinsheng Liang,Baizeng Fang,Yu’ang Piao,Ming Hao,Zishuo Wang
Low temperature NH3 selective catalytic reduction (NH3-SCR) technology is an efficient and economical strategy for cutting NOx emissions from power-generating equipment. In this study, a novel and highly efficient NH3-SCR catalyst, tourmaline-modified FeMnTiOx is presented, which was synthesized by a simple one-step sol–gel method. We found that the amount of tourmaline has an important impact on the catalytic performance of the modified FeMnTiOx-based catalysts, and the NOx conversion exceeded 80% from 160 to 380 °C with the addition of 5 wt % tourmaline. Compared with the pure FeMnTiOx, the catalytic efficiency at a temperature below 100 °C was increased by nearly 18.9%, and the operation temperature window was broadened significantly. The enhanced catalytic performance of the FeMnTiOx catalyst was mainly attributed to the small spherical nanoparticles structure around the tourmaline powders, resulting in the increased content of Mn3+, Mn4+, and chemical oxygen on the catalytic surface. These as-developed tourmaline-modified FeMnTiOx materials have been demonstrated to be promising as a new type highly efficient low temperature NH3-SCR catalyst.
研究领域:
环境科学
·
催化材料
·
能源工程
✓ 已验证
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Jiangxiao Qiao,Jinxin Gan,Fei Gao,Xiangsen Xu,Jiesong Tan,Yiqing Zeng,Feng Zhang,Feng Han,Zhaoxiang Zhong,Weihong Xing
Synergistic removal of nitrogen oxides (NOx) and particulate matter (PM) can be achieved using multifunctional catalytic membranes. In this work, CePO4 nanorods were loaded on the pore surfaces of SiC membranes to construct the CePO4/SiC-X catalytic membranes. The stacked nanorod structure of the CePO4 catalyst layer facilitates the diffusion of gases to the catalyst surface during reactions. Owing to the high specific surface area, rich surface acidity, and strong redox capacity, the CePO4/SiC-400 catalytic membrane exhibits the best ammonia-selective catalytic reduction (NH3–SCR) denitration activity, achieving >90% NO conversion at a temperature of 250–380 °C and negligible N2O byproduct. In addition, the CePO4/SiC-400 catalytic membrane demonstrates excellent H2O and SO2 resistance. The performance of dust filtration and simultaneous dust filtration and denitration at 250–350 °C proposed that the dust rejection efficiency reached more than 99% at various conditions, and the dust filtration process did not affect the NH3–SCR performance of the CePO4/SiC-400 catalytic membrane. From the above results, the CePO4/SiC-400 catalytic membrane presents a broad application prospect in the simultaneous dust removal and denitration of high-temperature flue gas.
研究领域:
环境科学
·
催化材料
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
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
PLoS One
·
2018
·Vol. 13
·期 4
·e0192324
·
IF 2.766
Hai-qian Zhao,Zhong-hua Wang,Xing-cun Gao,Cheng-hao Liu,Han-bing Qi
H 2 O 2 was adopted to oxidize NO in simulated flue gas at 100–500°C. The effects of the H 2 O 2 evaporation conditions, gas temperature, initial NO concentration, H 2 O 2 concentration, and H 2 O 2 :NO molar ratio on the oxidation efficiency of NO were investigated. The reason for the narrow NO oxidation temperature range near 500°C was determined. The NO oxidation products were analyzed. The removal of NO x using NaOH solution at a moderate oxidation ratio was studied. It was proven that rapid evaporation of the H 2 O 2 solution was critical to increase the NO oxidation efficiency and broaden the oxidation temperature range. the NO oxidation efficiency was above 50% at 300–500°C by contacting the outlet of the syringe needle and the stainless-steel gas pipe together to spread H 2 O 2 solution into a thin film on the surface of the stainless-steel gas pipe, which greatly accelerated the evaporation of H 2 O 2 . The NO oxidation efficiency and the NO oxidation rate increased with increasing initial NO concentration. This method was more effective for the oxidation of NO at high concentrations. H 2 O 2 solution with a concentration higher than 15% was more efficient in oxidizing NO. High temperatures decreased the influence of the H 2 O 2 concentration on the NO oxidation efficiency. The oxidation efficiency of NO increased with an increase in the H 2 O 2 :NO molar ratio, but the ratio of H 2 O 2 to oxidized NO decreased. Over 80% of the NO oxidation product was NO 2 , which indicated that the oxidation ratio of NO did not need to be very high. An 86.7% NO removal efficiency was obtained at an oxidation ratio of only 53.8% when combined with alkali absorption.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Junqi Cheng,Zhitao Han,Jiawei Li,Xinxiang Pan
Previous work proposed a one-stage wet scrubbing in situ combined with O3 oxidation for simultaneous removal of NO and SO2 from flue gas, and the results showed that wet scrubbing combined in situ with O3 injection could effectively improve O3 oxidant utilization efficiency. In this work, a follow-up research work was carried out to further explore the synergistic effect of dual oxidants of NaClO in the liquid phase and O3 in gas phase. The synergistic effects of O3/NO molar ratio and NaClO concentration in the circulating scrubbing solution on NOx removal performance was investigated systematically. The results showed that when molar ratio of O3/NO was 0.5 and NaClO concentration was 25 mM, NO could be oxidized completely and averaged NOx removal efficiency exceeded 70%. NOx concentrations in outlet gas and anion compositions in the scrubbed solution were analyzed, and the possible reaction paths of wet scrubbing NaClO solution in situ with O3 injection in denitration process were also discussed. When the solution pH was around 6, a relative balance between NOx oxidation and absorption might be achieved, resulting in a high NOx removal efficiency. The temperature of inlet flue gas imposed little impact on NOx removal efficiency due to the quick and efficient cooling effect by wet scrubbing. The increase of initial SO2 concentration led to a slight increase of NOx removal efficiency from 70 to 73.5%. A complete removal of SO2 could be achieved, but coexisting SO2 in flue gas would consume NaClO oxidant and shorten the reaction duration.
研究领域:
环境科学
·
化学工程
✓ 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）