Environmental Science-Nano
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2023
·Vol. 10
·期 11
·3149-3155
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IF 7.3
Hang Zhang,Kang Liu,Yingkang Chen,Xiaojian Wang,Hongmei Li,Junwei Fu,Liyuan Chai,Zhang Lin,Min Liu
CF4 is the most emitted perfluorocarbon (PFC) and possesses a great global warming potential (GWP) of 7390 with a lifetime of 50 000 years. Catalytic hydrolysis is a promising method for reducing CF4 emissions; however, the HF product can easily poison the catalyst, resulting in poor stability. In this study, a strategy for resisting HF corrosion by enhancing the order of aluminum-oxide polyhedron is originally demonstrated. HF corrosion experiments indicated that the Al2O3 catalysts with a higher order of aluminum-oxide polyhedron exhibited better resistance to HF corrosion (HF corrosion reaction rate k2, γ-Al2O3: 1.34 × 10−3, θ-Al2O3: 1.90 × 10−5, and α-Al2O3: 1.30 × 10−5). The obtained θ-Al2O3 achieved a lifetime of 100 h with 100% decomposition of CF4 at 750 °C, which is ∼20 times that of the γ-Al2O3 catalyst, and α-Al2O3 was inactive for CF4 decomposition. Theoretical calculations also demonstrated that θ-Al2O3 had lower adsorption and higher reaction barriers with HF than those of γ-Al2O3, proving the high stability of θ-Al2O3. This study provides a new inspiration for the development of efficient and stable CF4 decomposition catalysts.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
Journal of Environmental Sciences
·
2021
·
IF 5.565
Chang Cui,Yan Zhang,Wenpo Shan,Yunbo Yu,Hong He
Alumina supported Pd catalyst (Pd/Al 2 O 3 ) is active for complete oxidation of methane, while often suffers transient deactivation during the cold down process. Herein, heating and cooling cycle tests between 200 and 900°C and isothermal experiments at 650°C were conducted to investigate the influence of NO x on transient deactivation of Pd/θ-Al 2 O 3 catalyst during the methane oxidation. It was found that the co-fed of NO alleviated transient deactivation in the cooling ramp from 800 to 500°C, which was resulted from the in situ formation of NO 2 during the process of methane oxidation. Over the Pd/θ-Al 2 O 3 , thermogravimetric analysis and O 2 temperature programmed oxidation measurements confirmed that transient deactivation was due to the decomposition of PdO particles and the hysteresis of Pd reoxidation, while the metal Pd entities were less active for methane oxidation than the PdO ones. CO pulse chemisorption and scanning transmission electron microscopy characterizations rule out the NO 2 effect on Pd size change. Powder X-ray diffraction and X-ray photoelectron spectroscopy characterizations were used to obtain palladium status of Pd/θ-Al 2 O 3 before and after reactions, indicating that in lean conditions at 650°C, the presence of NO 2 increases the content of active PdO on the catalyst surface, thus benefits methane oxidation. Homogeneous reaction between CH 4 , O 2 , and NO x may be partially responsible for the alleviation above 650°C. The interesting research of alleviation in transient deactivation by NO x , the components co-existing in exhausts, are of great significance for the application.
研究领域:
催化化学
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环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE CHINESE CHEMICAL SOCIETY
·
2025
·
IF 1.5
Hongli Yang,Ting Li,Panpan Chang,Jinshi Dong
As an important transitional alumina phase, θ-Al 2 O 3 , its structural stability directly impacts the thermodynamic properties and potential applications. In this study, the unit cell structure of θ-Al 2 O 3 was determined through Rietveld XRD refinement, and it was found that the occupancies of both two types of Al sites and two of three types of O sites were less than 1. A 1 × 5 × 2 supercell (Al 80 O 120 ) was constructed, and the effect of each type of defect on the stability of the structure was determined by molecular dynamics simulations and the calculations of the probability distribution function of the distance to mass center (P(r)) during heating. It was found that defects at the Al1 sites are more likely to cause structural instability than those at the Al2 sites; the O3 defect brings poor thermal stability to the structure due to its low occupancy.
研究领域:
材料科学
·
陶瓷
·
计算材料学
·
固态化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2026
·
IF 12.5
Jincheng Luo,Zhigang Yi,Jialin Zheng,Song Xie,Dewei Liu,Zhu Zu,Yuxiang Liu,Pansong Li,Yusen Xiao,Kang Liu,Zhiqiang Sun,Xing Peng,Min Liu
CO and steam drive the self-optimization of Pt/θ-Al 2 O 3 during SMR. • Surface Pt–CO species facilitate Pt redistribution into dispersed sites. • The dispersed Pt species enhance methane adsorption and activation under working conditions. • 0.1 wt% Pt gives >93% CH 4 conversion with near-unity H 2 selectivity at 700 °C. • Ce promotion suppresses long-term Pt sintering while preserving high activity. Maximizing noble-metal utilization under harsh reaction conditions remains a fundamental challenge in heterogeneous catalysis, as high temperatures typically drive irreversible metal sintering. Here, we report a reaction-atmosphere-driven dynamic dispersion mechanism that enables the in situ self-optimization of Pt/Al 2 O 3 catalysts during steam methane reforming (SMR). We show that the coexistence of steam and in situ generated CO promotes the progressive restructuring of Pt species toward highly dispersed, low-coordination metallic sites during activation. Spectroscopic analyses suggest that CO-containing intermediates may facilitate Pt restructuring through the formation of surface Pt–CO species, while steam induces the formation of surface hydroxyl groups on Al 2 O 3 that may help stabilize dispersed Pt species. This atmosphere-assisted restructuring process increases the number of accessible Pt surface sites during activation and improves Pt utilization under SMR conditions. As a result, an ultralow-loading Pt catalyst (0.1 wt%) achieves >93% CH 4 conversion with near-unity H 2 selectivity at 700 °C, together with an apparent TOF nearly an order of magnitude higher than that of higher-loading counterparts. Furthermore, moderate strengthening of metal-support interactions via Ce modification effectively suppresses long-term sintering without compromising activity. This work introduces a dynamic dispersion paradigm in which the reaction atmosphere actively governs catalyst structure under operating conditions, providing a general strategy for designing self-adaptive catalysts with maximized noble-metal efficiency in high-temperature reactions.
✓ 已验证
产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2026
·
IF 4
Yueqi Wang,Yu Niu,Qinglian Wang,Wang Yin,Yixiong Lin,Ting Qiu,Jiafang Gu,Chen Yang
Liquid organic hydrogen carriers (LOHCs) are considered one of the ideal media for hydrogen storage and transportation. Achieving efficient cyclic utilization of LOHCs necessitates the development of highly active dehydrogenation catalysts. This work focuses on optimizing Pt/θ-Al2O3 catalysts for the dehydrogenation of Perhydro Benzyltoluene (H12-BT). Catalysts with Pt loadings ranging from 0.3 to 5.0 wt% were synthesized via impregnation, yielding Pt particle sizes between 2.1 and 7.1 nm. Surface acidity was systematically tuned by introducing nitric acid (HNO3) during impregnation, with HNO3/Pt molar ratios (n) varying from 0 to 24. Dehydrogenation testing revealed a distinct volcano-shaped dependence on Pt particle size. The peak activity, corresponding to 3.0 nm particles at 1 wt% loading, reached a dehydrogenation degree (DoDH) of 48.3% under optimal conditions (250 °C, 4h). HNO3 modification (n = 12) further enhanced performance under the same conditions, elevating the DoDH to 58.7%. Studies of the adsorption behavior revealed that the size effect competes with geometric and electronic influences: small Pt particles (<3nm) facilitated H12-BT adsorption but impeded product H2 desorption, whereas large particles (>5nm) exhibited insufficient active sites despite enhanced H2 desorption. Concurrently, optimized Lewis acid site distribution and strength dynamically balanced H12-BT adsorption capacity and product desorption behavior. This work elucidates the interplay between Pt particle size, acid site distribution, and adsorption-desorption behavior, providing a framework for designing efficient LOHCs dehydrogenation catalysts.
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Chunmei Li,Pingfan Zhang,Fang Gu,Lei Tong,Jizhou Jiang,Yan Zuo,Hongjun Dong
A new Au-θ-Al 2 O 3 /Au/PCN hybrid is fabricated by the collaborative design strategy of active site and assembled structure, which achieves highly efficient photocatalytic CO 2 reduction (CO 2 R) performance. The energy band structure of PCN is adjusted significantly owing to the strong coupling effect of Au-θ-Al 2 O 3 /Au nanosheets intercalated in PCN nanosheets. The result brings about up-shift of CB, VB and Fermi energy level overall and decrease of bandgap, which is in favor of harvesting visible light, exciting VB electrons and increasing reduction ability. In addition, the multiple built-in electric fields are induced by electron diffusion effect between structural units, due to the tight interface contact in the Au-θ-Al 2 O 3 /Au/PCN hybrid, which can effectively promote the separation of photoinduced charge carriers. Furthermore, the atomically dispersed Au atoms confined by the oxygen vacancies in Au-θ-Al 2 O 3 /Au can provide the plenty of effective active sites for CO 2 R reaction, and meanwhile, the localized surface plasmon resonance (LSPR) effect induced by Au nanoparticles on Au-θ-Al 2 O 3 /Au can improve the visible light response and produce abundant hot electrons to contribute to CO 2 R reaction. As a consequence, the average CO evolution rate of over the optimizing 10 %-Au-θ-Al 2 O 3 /Au/PCN hybrid (7.76 μmol g -1 h −1 ) reaches up to 3.53 times than that of PCN (2.20 μmol g -1 h −1 ) in the CO 2 R reaction, and maintains basically stable operation within 7 cycles of running, suggesting the superior activity and recyclability.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
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