APPLIED CATALYSIS A-GENERAL
·
2018
·
IF 4.521
Xiaoqiang Wang,Yue Liu,Qingji Ying,Weiyuan Yao,Zhongbiao Wu
In this paper, a series of Nb modified Cu-Ce-Ti mixed oxides (Nb y CCT) were synthesized using wetness impregnation method for the selective catalytic reduction of NO with ammonia (NH 3 -SCR). The activity tests indicated that Nb y CCT catalysts had shown superior SCR performances. Among which, Nb 0.05 CCT catalyst exhibited a NO conversion of more than 90% within a broad operation temperature window (180–360 °C) under the GHSV of 40,000 h −1 . After that, corresponding characterizations were performed to correlate the physical structures and surface properties to catalytic performances. These results revealed that the strong interactions among the active phases induced by Nb addition could not only enhance the redox property of the catalysts but also inhibit the over-oxidation of NH 3 , which would be beneficial to SCR performance within a wide temperature range and good reaction selectivity. Furthermore, DRIFTS results suggested that the doping of Nb could promote the formation of NO 2 , thereby enhancing the “fast” SCR reaction process (Langmuir-Hinshelwood reaction pathway). Moreover, the Nb 0.05 CCT catalyst showed a better sulfur tolerance compared to Nb free catalyst that over 85% NO conversion could be retained after 12 h SCR reaction in the presence of SO 2 and H 2 O.
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高影响因子
Molecular Catalysis
·
2018
·
IF 0
Sher Ali,Yushi Li,Tianrui Zhang,Syed ul Hasnain Bakhtiar,Xuesong Leng,Zhibin Li,Fulong Yuan,Xiaoyu Niu,Yujun Zhu
Citric acid method was employed to prepare a series of Nb-promoted Fe x -Nb 0 . 5- x -Ce 0.5 ( x = 0.45, 0.4, 0.35) oxides for selective catalytic reduction with NH 3 (NH 3 -SCR) of NO process. The structure, redox ability and reactivity of NH 3 and absorbed NO species on the catalysts were explored by using various characterization techniques such as X-ray diffraction (XRD), temperature program reduction with H 2 (H 2 -TPR), temperature program desorption of NH 3 (NH 3 -TPD), temperature program desorption of NO (NO-TPD), X-ray photoelectron spectroscopy (XPS) and in situ diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS). It was found that the Nb promoted Fe x -Nb 0 . 5- x -Ce 0.5 ( x = 0.45, 0.4, 0.35) oxides catalysts showed outstanding NH 3 -SCR of NO activity, excellent N 2 selectivity and remarkable SO 2 /H 2 O resistance, meanwhile, Fe 0.4 -Nb 0.1 -Ce 0.5 exhibited above 90% NO conversion in the range of 180–400 °C, together with near 100% N 2 selectivity. The characterization results point out that the excellent catalytic performance of Fe 0.4 -Nb 0.1 -Ce 0.5 can be ascribed to the strong interaction among Nb, Fe and Ce oxides. The strong interaction not only increases the BET surface area and redox ability of the catalyst, but also significantly improves the acid amount leading to the enhancement of the adsorption and activation of NH 3 , which is advantage of the reactivity of adsorbed nitrate together with the adsorbed NH 3 species.
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CHINESE JOURNAL OF CATALYSIS
·
2015
·
IF 1.964
Xin Zhao,Lei Huang,Hongrui Li,Hang Hu,Jin Han,Liyi Shi,Dengsong Zhang
Different transition metals were used to modify V 2 O 5 -based catalysts (M-V, M = Cu, Fe, Mn, Co) on TiO 2 via impregnation, for the selective reduction of NO with NH 3 . The introduced metals induced high dispersion in the vanadium species and the formation of vanadates on the TiO 2 support, and increased the amount of surface acid sites and the strength of these acids. The strong acid sites might be responsible for the high N 2 selectivity at higher temperatures. Among these catalysts, Cu-V/TiO 2 showed the highest activity and N 2 selectivity at 225–375 °C. The results of X-ray photoelectron spectroscopy, NH 3 -temperature-programmed desorption, and in-situ diffuse reflectance infrared Fourier transform spectroscopy suggested that the improved performance was probably due to more active surface oxygen species and increased strong surface acid sites. The outstanding activity, stability, and SO 2 /H 2 O durability of Cu-V/TiO 2 make it a candidate to be a NO x removal catalyst for stationary flue gas.
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高影响因子
Molecular Catalysis
·
2025
·
IF 4.9
Faraz Ahmad,Yueli Wen,Muhammad Zeeshan,Bin Wang,Samia Kausar,El Gharrabi Mohamed,Wei Huang
Achieving an optimal acid-base synergy and uniform dispersion of active sites on catalyst surface is essential for high catalytic performance in the side chain alkylation of toluene with methanol (SATM). Herein, we report that ammonium (NH₃) treatment of Cu-modified NaX zeolite catalysts effectively modulates acid-base properties and enhances the dispersion of Cu active sites across the catalyst surface. A series of Cu-modified catalysts were prepared with and without NH₃ treatment and further modified with NaOH to evaluate their synergistic effects. Comprehensive characterization techniques, including Scanning Electron Microscopy (SEM), HAADF-STEM and EDS, Pyridine FTIR, Temperature-Programmed Desorption of NH₃ (TPD-NH₃), X-ray Photoelectron Spectroscopy (XPS O 1 s), and regression analysis, were used to correlate catalyst structure, and acid-base property and nature of acid sites with catalytic performance. Results reveal that NH₃ incorporation into the Cu-modified NaX framework significantly enhances catalytic efficiency by tuning acid-base properties and promoting a homogeneous distribution of Cu active sites. Notably, the 3Cu-4Na-N catalyst achieved a superior yield of ethylbenzene and styrene production, reaching 84.9 %, compared to 64.3 % for the 3Cu-4Na catalyst under identical conditions. Methanol conversion reached 97.7 %, with the catalyst demonstrating robust stability over 168 h of operation. Additionally, 3Cu-4Na-N catalyst exhibited the highest turnover frequency (TOF) reaching 27.3 h -1 , confirming its superior intrinsic activity. This study highlights the critical role of NH₃ in advancing Cu-NaX catalysts for SATM and provides a promising strategy for optimizing catalytic performance through controlled acid-base interactions and active site dispersion.
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Sustainable Materials and Technologies
·
2024
·
IF 8.6
Lei Guo,Yan-He Chen,Li-Mei Xu,Xiao-Lu Chen,Jin-Qiu Shen,Jian-Yong Zhang,Zhen-Jiang Liu
Herein, a fern-like p-n heterojunction by anchoring Ni 3 Fe-LDH nanoplates onto Co 3 O 4 nanoneedles have been optionally constructed. Essentially, p-n heterojunction ensured to induce strong built-in electric field, and inherit interfacial electron redistribution. Based on their compatible and well-matched electronic band structures, a staggered type-II photo-generated electron/holes transfer pathway have been elaborated by density functional theory calculation (DFT), in situ irradiation X-ray photoelectron spectroscopy (XPS), and fluorescent decay. This band bending and charge migrating module conferred the architecture with strong redox ability, sufficient exciton dissociation, and admirable optoelectronic characteristics. Moreover, the heterostructure acquired broad absorption spectrum to exhibit outperforming photocatalytic effect. Totally, this electron redistribution at the hierarchical interface, a type-II scheme charge-transfer pathway and the oxygen defects would lead to high efficiency in solar light assisted N 2 reduction. Typically, Co@Ni 3 Fe-2 catalyst exhibited the highest NH 3 production rate of 16.15 μg h −1 mg cat. −1 and Faraday efficiency (FE) of 31.57% at −0.6 V vs. RHE in 0.1 M Na 2 SO 4 solution. Fortunately, with light exposure, the NH 3 production rate and FE could increase by 27.9% and 18.1% than that under dark. This work would provide a plausible attitude towards the design of high efficient photocatalyst for artificial photosynthesis with multi-functionalized coupling effect.
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高影响因子
Catalysis Science & Technology
·
2024
·Vol. 14
·期 10
·2929-2939
·
IF 4.4
Qian Xu,Zhihong Zheng,Jinjing Luo,Zheng Lai,Jianwen Chen,Jiaxin Shang
Supported MnFeOx catalysts have been prepared using Al2O3 as the substrate and were investigated for NH3-SCR. The 20% MnFe/Al2O3 catalyst removed over 80% of NOx with an N2 selectivity exceeding 90% at temperatures between 80 and 340 °C. The results from the various characterization studies indicated that the increased activity of MnFe/Al2O3 catalysts can be primarily linked to the increased chemisorbed oxygen species and Fe3+ concentrations, greater reducibility, and higher adsorption capacity for NH3. These characteristics are the outcome of the strong interaction, larger specific surface, and abundant acidic sites. Additionally, in situ DRIFTS analysis of the reaction mechanism revealed that the E–R and L–H mechanisms were responsible for the NH3-SCR reaction over the 20% MnFe/Al2O3 catalyst.
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Advanced Fiber Materials
·
2025
·
IF 21.3
Zhou Mi,Huang Lele,Wan Yuhang,Jiang Qing,Qu Xueru,Mia Md Hasib,Xu Jie,Gao Chao,Hou Lin,Yu Zhicai,He Hualing
Firefighting clothing provides essential safeguards for firefighters while engaging in fire suppression and life rescue operations. However, the inability to actively detect hazardous gas and self-thermal degradation of conventional firefighting clothing induce critical safety threats to firefighters. Herein, we design a dual-mode perceptual sensor via programmable assembly of single-walled carbon nanotubes (SWCNTs) and Ti 3 C 2 T x MXene@MoS 2 nanocomposite in dual-mode triaxial structural aerogel fiber (DM-TSF) for both selective NH 3 and temperature monitoring. The DM-TSF is prepared through triaxial wet spinning, with an alternating p / n -type thermoelectric (TE) core, a signal decoupling aramid nanofibers layer, and an NH 3 sensing outer sheath. The TE core is composed of alternately interconnected p -type/SWCNT and n -type SWCNT/Polyethyleneimine, which exhibits high TE efficiency (8.44 μV K −1 for p -segment, 7.44 μV K −1 for n -segment) and wide-range (10–500 °C) temperature monitoring in DM-TSF. Furthermore, the abundant adsorption sites and high-density Schottky heterojunctions of the Ti 3 C 2 T x MXene@MoS 2 nanocomposite in the outer sheath enabled DM-TSF to exhibit an outstanding sensitivity (3.14% ppm −1 @20 ppm) and high selectivity for NH 3 . A portable wireless system based on DM-TSF was further developed and integrated into firefighting clothing for temperature and NH 3 monitoring, triggering alarms within 2 s and 28 s, respectively. This work sheds new light on the fabrication of intelligent multiplex hazard detection fibers that can respond to multi-hazard elements, thereby enhancing firefighters’ safety in complex fire scenarios. Graphical
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Wei Han,Xin Ge,Jili Yuan,Ronglan Pan,Yao Yang,Guanglong Zou,Haibo Xie
Nitrate (NO 3 − ) Electroreduction to produce NH 3 offers an alternative approach to sustainable production of NH 3 . Yet it remains challenging to simultaneously improve the adsorption and enrichment of low-concentration NO 3 − . Here, bundles of CuO x microneedles on TiO 2 nanotubes (NTs) were developed by a spatial-confined electrodeposition strategy, achieving 87.7 % or 98.4 % NH 3 FE at −0.25 V or −0.45 V vs RHE in 2 or 10 mM NO 3 − electrolytes, respectively. Both in-situ spectroscopy and finite element analysis simulation demonstrated that CuO x microneedle bundles and its interface between TiO 2 NTs not only greatly improve the enrichment of low concentration NO 3 − and its derived-NO 2 − and the diffusion of NH 3 product, but also enhance the adsorption of NO 2 − and H 2 O to facilitate the hydrodeoxygenation of NO 3 − as well as inhibit hydrogen evolution reaction competition. This work will provide a promising avenue to develop electrocatalysts to realize efficient catalytic conversion of reactants at low concentrations.
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CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Yeguang Zhang,Zichang Zhang,Guangqiang Chen,Shuni Li,Feihu Li,Shuzhuang Sun,Peng Wang,Fang Fang,Jingmin Ge,Zili Zhan
Developing highly selective and fast NH 3 gas sensors operable at room temperature (RT) has significant application value but remains challenging. Herein, Ni-NiO@polyaniline (PANI) nanocomposites (NNOPs) were fabricated by thermal treatment of Ni foam and in situ polymerization of aniline. NNOPs exhibit p-n response transitions and rapid response rates to NH 3 at room temperature under varying amounts of PANI loading. The maximum response to 100 ppm NH 3 is 143.7 % and the response/recovery time was 22/40 s, which is 3181 % shorter than the response time of pure PANI (700 s). The unique response transition can significantly enhance the selectivity of NH 3 sensing. Additionally, NNOPs also demonstrate excellent repeatability, long-term stability, and humidity insensitivity. The outstanding sensing performance can be attributed to the ohmic contact between Ni and NiO, the oxygen vacancies induced by PANI surface modification and the large specific surface area. The high selectivity and fast NH 3 response of NNOPs sensors at RT hold great value for applications in fields such as internet of things and flexible electronics.
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Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Xinyu Li,Huawang Zhao,Yating Huang,Xiaomin Wu,Zhiwei Huang,Huazhen Shen,Guohua Jing
A composite catalyst was prepared by mechanically mixing Cu-SSZ-13 and MnCeTiO x to improve selective catalytic reduction (SCR) of NO x by ammonia. The optimal mass ratio of Cu-SSZ-13 and MnCeTiO x components in the composite catalysts was 1:1, where the NO x conversion was improved by around 40% in the temperature range of 150–300 °C compared with Cu-SSZ-13 alone. MnCeTiO x presented significantly stronger ability on the activation of NO to nitrates species than Cu-SSZ-13. Infrared (IR) and density functional theory (DFT) results showed that active nitrates intermediate on MnCeTiO x might migrate to Cu-SSZ-13, which assisted the oxidation of single Cu + to Cu 2+ to complete the Cu redox cycle. This avoided the rate-determining step that formation and oxidation of Cu + dimers in low-temperature SCR over Cu-SSZ-13. The research results are beneficial to the rational design of SCR catalysts with high-performance at low temperatures.
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高影响因子
ENVIRONMENTAL TECHNOLOGY
·
2015
·
IF 1.56
Qunxing Huang,Xu Cai,Moussa Mallaye Alhadj Mallah,Yong Chi,Jianhua Yan
The high concentration of heavy metals in solid wastes may cause serious pollution during thermal treatment. We have investigated, theoretically and experimentally, the effects of several important flue gas species and mineral sorbents on the partitioning behaviour of four major heavy metals (cadmium, lead, zinc and copper) which are often present in municipal solid waste (MSW). Their concentrations in bottom ash, fly ash and flue gas were quantified when model MSW samples were treated thermally under different conditions. The evaporation ratio of the four metals, excluding Cu, increased with decreasing oxygen concentration. The presence of HCl promotes heavy metal evaporation by preventing the formation of stable metallic species, especially for Zn (evaporation of more than 20%). An increase in oxygen concentration has a negative influence on the effect of HCl. In the presence of SO2, Cd and Pb exhibited a higher evaporation ratio, while Zn and Cu were insensitive to the change. SO2 also inhibits Cd vaporization in an oxidative atmosphere. The effect of NH3 on reducing the metal volatilization rate was established indirectly. Calcium oxide addition enhances metal evaporation except for that of Zn (which shows a decrease of 38%). Although desulphurization by calcium injection decreases the volume of acid gas, calcium affects heavy metal pollution control adversely. The presence or addition of SiO2- or Al2O3-containing minerals can lead to the formation of stable metallic salts. This may favour the control of Cd, Pb, Zn and Cu volatilization up to 13%, 50%, 17.5% and 19%, respectively.
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PubMed
高影响因子
LANGMUIR
·
2026
·
IF 4.4
Li Daiqiang,Liu Yang,Zhang Runduo,Di Zhaoying,Guo Xiaonan
The fabrication of highly uniform and dispersed catalysts
is achievable
through atomic layer deposition (ALD). However, the application of
this method in porous materials is largely restricted by the size
compatibility between the host and the guest molecules. In this study,
we coupled ALD with different Cu-based catalysts to develop an interfacial
engineering strategy for the selective catalytic oxidation of ammonia
(NH 3 –SCO). Using Cu(hfac) 2 as the precursor,
it was demonstrated that the pore structure served as a critical steric
gatekeeper. Unhindered mass transfer pathway was observed in mesoporous
Al-SBA-15, which successfully accommodated the large precursors. This
led to a high copper loading of 1.58 wt % along with high interfacial
dispersion. On the contrary, the narrow pores of microporous zeolites
caused significant pore-mouth blockage and external accumulation because
of the size exclusion effect. Therefore, superior intrinsic catalytic
activity was found in the Cu-Al-SBA-15, realizing complete NH 3 conversion at 350 ° C combined with excellent N 2 selectivity. Comprehensive characterizations indicated that a large
proportion (75.64%) of active mononuclear [Cu(OH)] + species
was stabilized by the abundant mesopores and numerous anchoring sites.
These findings provide fundamental information regarding the size-exclusion
mechanisms in ALD, suggesting a potential material design to precisely
control metal–support interfaces for catalysis.
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