JOURNAL OF CATALYSIS
·
2024
·
IF 6.5
Ruoyuan Li,Aixia Li,Junhua Li,Yao Wang,Zhiming Liu
Selective catalytic reduction of NO x by CO (CO-SCR) in the presence of O 2 is challenging because in this process CO is prone to being oxidized by O 2 , thus inhibiting NO x reduction by CO. Furthermore, SO 2 typically leads to the deactivation of the CO-SCR catalyst. Herein, a significant promoting effect of SO 2 on Ir/SiO 2 catalyst for the CO-SCR of NO x in the presence of O 2 is reported. In-situ X-ray Absorption Fine Structure (XAFS) and X-ray photoelectron spectroscopy (XPS) analysis showed that SO 2 does not affect the chemical nature of Ir 0 under reaction conditions. However, SO 2 can be oxidized to sulfate and deposit on the catalyst surface. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis demonstrated that the presence of SO 2 can inhibit the CO + O 2 reaction, thus leaving more CO available to reduce NO x over the active Ir 0 sites. As a result, the reduction of NO x is remarkably promoted even in the presence of O 2 and SO 2 .
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
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2025
·
IF 21.1
Yixi Wang,Wenqing Xu,Zhi Liu,Yulong Shan,Wanrong Chen,Xinyu Zhang,Tingyu Zhu
Controlling both CO and NOx pollutants without additional cost is necessary but challenging, especially in industrial flue gas with complex components. Previous studies mainly focused on the effect of O 2 and SO 2 on the CO oxidation side reaction and valence state of Ir species on various catalysts, while neglecting the impact on NO conversion pathway. Herein, we propose an "ineffective reaction pathway" in the presence of O 2 with nitrate as an intermediate according to the results of in situ DRIFTS and DFT. And we also reveal the contribution of SO 2 in inhibiting the adsorption of O 2 and promoting the selective adsorption of NO and CO even at lower injection concentrations, based on the oxidation of SO 2 on Ir(111). This is quite a favorable characteristic for the treatment of industrial flue gas, resolving the long–standing dispute on the involvement of these components in the CO–SCR reaction. Under specific conditions (CO/NO=20, O 2 =5%, SO 2 =200 ppm) at 250 °C, the NOx conversion is as high as 78%. These results will contribute to the development of more efficient catalysts in the future for simultaneously controlling two pollutants (CO and NOx).
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 Environmental Chemical Engineering
·
2023
·
IF 7.7
Liu Yang,Jing Li,Guoqiang Cao,Yiyan Yang,Wen Luo,Zhiqi Zhang,Lizhi Feng,Xinglai Zhang,Baodan Liu
This study reports on the development of highly-efficient Pt/CuO-Fe 2 O 3 /TiO 2 monolithic catalysts for the low-temperature conversion of NO to N 2 via CO-SCR. In this case, ultrathin TiO 2 nanosheet arrays are designed to in situ grow on flexible Ti mesh to provide more spaces/areas for the loading of highly-dispersed Fe 2 O 3 and CuO active components. Furthermore, Pt nanoparticles with an average size of 1.30 nm are effectively decorated on the surface of CuO-Fe 2 O 3 /TiO 2 . The H 2 -TPR and NO-TPD results demonstrate that the excellent synergistic effect between TiO 2 , CuO, Fe 2 O 3 and trace amounts of Pt is conducive to enhance the adsorption of NO and finally promote the CO-SCR. The obtained Pt/CuO-Fe 2 O 3 /TiO 2 catalysts exhibit excellent CO-SCR performance with 100 % NO conversion, and 100 % N 2 selectivity at 250 °C, showing great potential of de-NO x application by using toxic CO as reductant in industry.
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
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Yuqing Pan,Na Li,Ke Li,Shiyuan Ran,Chenyang Wu,Qulan Zhou,Jiyuan Liu,Shuzhou Li
The industrial applications of de-NOx require the high activity window of the catalysts to be shifted from high to low temperatures for energy saving. Selective catalytic reduction (SCR) of NOx by CO, as an alternative to NH 3 -SCR, is a promising de-NOx technology that facilitates the synergistic removal of pollutants. Herein, we report a new Fe 2 O 3 /amorphous SiO 2 catalyst with high low-temperature activity for CO-SCR. A combination of experiments and density functional theory (DFT) calculations obtains direct evidence that an optimal content of oxygen vacancy enhances the low-temperature NO conversion ratio and N 2 selectivity of Fe 2 O 3 -based catalyst to over 80% and maintain 100% CO conversion by promoting NN coupling via ONNO/N 2 O and NCO/NNCO 2 intermediates. Compared with conventional defect engineering, such as doping other metals or artificially generating oxygen defects, the α-Fe 2 O 3 (1 1 0) facet automatically enables an oxygen vacancy generation-filling cycle in the CO-SCR reaction, following Mars-van Krevelen (MvK) mechanism. This work advances a fundamental understanding of CO-SCR reaction mechanism over Fe 2 O 3 -based catalysts and provides insights for future studies to improve heterogeneous metal oxide catalysts.
研究领域:
催化化学
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2022
·
IF 13.7
Yongjun Ji,Shaomian Liu,Shaojia Song,Wenqing Xu,Liang Li,Yu Zhang,Wenxing Chen,Huifang Li,Jingang Jiang,Tingyu Zhu,Zhenxing Li,Ziyi Zhong,Dingsheng Wang,Guangwen Xu,Fabing Su
Pt-based catalysts are promising for the selective catalytic reduction of NOx by CO (CO-SCR), but some technical issues hinder their practical application, including the high Pt loading needed, high reduction temperature, and the low tolerance toward SO2. Here, we report a novel Pt catalyst for CO-SCR, which has negatively charged single-atom Pt embedded on CuO squares, and the latter is supported on CoAlO nanosheets. This Pt–CuO/CoAlO catalyst with an ultra-low Pt loading (0.02 wt %) exhibited 91% NO conversion and 80% N2 selectivity in 3% O2 at 200 °C. More importantly, it showed almost no activity loss in 200 ppm SO2 over a 15 h test. The theoretical calculations reveal that the negatively charged Pt has a stronger NO adsorption ability than the positively charged Pt, and Cu serves as the CO adsorption site. The much-weakened SO2 adsorption on Pt–CuO/CoAlO relative to the NO and CO adsorption effectively avoids the catalyst poisoning by SO2.
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
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Kaiting Chen,Xinyu Han,Qian Wang,Kaijie Liu,Xiangguang Yang,Yibo Zhang
The selective catalytic reduction of NO by CO (CO-SCR) presents an economical and promising approach to mitigate emissions of NO x and CO from motor vehicles. A bimetallic Rh-Mn supported catalyst Rh-Mn/CoAlO was synthesized through the reduction of citric acid and ethylene glycol, and subsequently employed in the CO-SCR reaction. Tests assessing its catalytic performance revealed that the Rh-Mn/CoAlO catalyst displayed superior CO-SCR activity, maintaining high efficiency (≥90 % at 230 °C) and stability while simultaneously reducing the usage of noble metals. Various characterization techniques, including H 2 -TPR, NO-TPD, CO-pulse, and XPS, indicated that the Rh-Mn/CoAlO catalyst possessed enhanced dispersion of noble metals. This increased dispersion ensured optimal contact between Rh and Mn, as well as the support, fostering a synergistic interaction that facilitated electron transfer. Consequently, the catalyst’s adsorption and activation capabilities for NO were significantly improved. In situ DRIFTs studies further elucidated that the catalyst primarily followed the E-R mechanism, wherein NO is adsorbed onto the catalyst surface, and subsequently, the N and O atoms generated from pyrolysis react with CO in the gas phase. The findings of this study are anticipated to offer an effective strategy for designing catalysts with exceptional low-temperature activity and high dispersibility for the reduction of NO using CO.
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 Environmental Chemical Engineering
·
2023
·
IF 7.7
Chen Cai,Jiayin Chen,Wei Fu,Shuying Ning,Hao Zhou,Muhammad Kashif,Yaxin Su
The Ce-modified OMS-2 catalyst (Ce x -OMS-2) was synthesized by the hydrothermal synthesis method, after which its catalytic efficacy in the selective reduction of NO by CO was assessed. The experiments showed that Ce 0.08 -OMS-2 was capable of 100% NO conversion between 175 and 300 °C when 0.05%NO, 0.1%CO, 5%O 2 and N 2 were used as equilibrium gases, and the N 2 selectivity peaked at 93.2% at 175 °C. Additionally, Ce 0.08 -OMS-2 exhibits good sulfur resistance in the presence of 0.02% SO 2 and maintains more than 88% NO conversion at 175–275 °C. By using BET, XPS, H 2 -TPR, NH 3 -TPD, and In situ DRIFTS to characterize the catalysts, the effects of doping the active metal Ce on the physicochemical characteristics of OMS-2 catalysts were under investigation. In conclusion, the improvement of the low-temperature activity of the Ce x -OMS-2 catalyst is facilitated by lower agglomeration and crystallinity , larger specific surface area, smaller average pore size, enhanced surface oxygen vacancies, increased Mn 4+ concentration, and richer Brønsted acid. Reaction gas adsorbed species and intermediates on the catalyst surface were dynamically captured during In situ DRIFTS experiments. The CO-SCR reaction of the catalyst was found to follow the E-R mechanism below 200 ℃ and the L-H mechanism at 200–350 ℃.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
MOLECULES
·
2025
·Vol. 30
·期 5
·1133
·
IF 4.6
Yuansong Zhou,Fengyu Gao,Lei Yi,Junyi Wang,Honghong Yi,Xiaolong Tang
In an O 2 -containing environment, achieving efficient selective catalytic reduction of nitrogen oxides (NOx) by carbon monoxide (CO) using non-noble metal catalysts remains a formidable challenge. To balance the catalytic oxidation of CO and the catalytic reduction of NOx, we need to develop a catalyst with strong reductibility and weak oxidizability for the CO selective catalytic reduction of NOx (CO-SCR) reaction in the presence of O 2 . In this study, we synthesized the CoCeOx-PVP catalyst via a coprecipitation method and employed various characterization techniques, including BET, SEM, XRD, Raman, XPS, H 2 -TPR, and O 2 -TPD. The analysis results indicate that the addition of polyvinylpyrrolidone (PVP) alters the surface structure of the catalyst, increases the particle size, and enhances the concentration of surface oxygen vacancies. These structural effects facilitate electron circulation and accelerate the migration of oxygen species, thereby improving the catalytic reduction performance of the catalyst and increasing the conversion rate of NOx. At 250 °C and with 5 vol% O 2 , the conversion rates of NOx and CO can attain 98% and 96%, respectively, accompanied by a remarkable N 2 selectivity of 99%. Following a sustained reaction period of 6 h, the conversion efficiencies of both NOx and CO remain above 95%. However, during extended testing periods, as the oxygen vacancies are progressively occupied by O 2 , the oxygen vacancies generated through the reduction of NO with CO fall short of sustaining the CO-SCR reaction over the long haul. Subsequently, the oxidation reactions of NO and CO come to dominate, resulting in a decline in the NOx conversion rate. Notably, the CO conversion rate still maintains 100% at this point. Based on the results of in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) experiments, we proposed a reaction mechanism for the CO-SCR process over the CoCeOx-PVP catalyst under O 2 -containing conditions. This study provides an effective strategy for the application of non-noble metal catalysts in the field of CO-SCR. Although maintaining long-term activity of the catalyst remains a challenge in the presence of O 2 , the catalyst in this study exhibits a slower deactivation rate compared to traditional non-noble metal catalysts.
研究领域:
催化化学
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2023
·
IF 7.4
Yuxin Sun,Yunshuo Wu,Yarong Bai,Xuanhao Wu,Haiqiang Wang,Zhongbiao Wu
Iridium nanocatalysts are ideal candidates for the selective catalytic reduction of NO x by CO (CO-SCR) in excess oxygen. Here, a high-performance Ir nanocatalyst supported on natural halloysite nanotubes (HNTs) was applied for the CO-SCR. The HNTs loaded with only 0.5 wt% Ir achieved 78 % NO x conversion at 250 °C in the presence of 5 % O 2 , which was the highest among catalysts with varied Ir loadings or reduction temperatures. It also possessed an excellent SO 2 and H 2 O tolerance during longevity tests. An interesting SO 2 -enhanced CO-SCR long-term stability was observed, which was ascribed to the inhibitory effects of SO 2 on the side reaction between CO and O 2 . The loading amount and the reduction temperature could modulate the size of Ir nanoparticles and the percent of Ir 0 , which were two key factors determining the CO-SCR activity. DRIFTS characterizations and DFT calculations coherently revealed the favorable adsorption sites of CO (top) and NO (hcp) on Ir nanoparticles. The Ir atoms served as a charge transfer bridge from the C atom of CO to the N atom of NO, leading to the enhanced breakage of N-O bonds. This work provides Ir/HNT as a promising CO-SCR material with high performance and robustness to tackle NO x pollution.
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
危险品化学品经营许可证（带存储）