CHEMICAL ENGINEERING SCIENCE
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2025
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IF 4.3
Yuxia Zhong,Zhihua Zhang,Min Zhang,Yujie Liao,Shudong Shi,Wenyao Chen,Liang Wang,Xinggui Zhou,Xuezhi Duan
The selective oxidation of alkanes is challenging due to the inertness of C–H bonds and the tendency for overoxidation to COx. Metal-zeolite catalysts offer a promising solution by spatially decoupling oxygen and C–H bond activation on distinct active sites. This study introduces a strategy using surface hydrophobic modification of titanium silicalite-1 (TS-1) zeolites to achieve high selectivity in propane oxidation to acetone. Hydrophobic organosilanes with methyl groups were applied via a one-step co-condensation process, followed by Au nanoparticle immobilization. The hydrophobic groups prolong the residence time of the intermediate isopropanol on the catalyst surface, enhancing its conversion to acetone while stabilizing H 2 O 2 to prevent excessive oxidation of carbon-containing species into CO 2 during the process. The modified TS-1 demonstrated excellent thermal stability and selectivity, particularly under extreme hydrogen-to-oxygen ratios conditions. The alkylated Au/TS-1 catalysts significantly improved acetone production, providing a new pathway for selective alkane oxidation.
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CATALYSIS TODAY
·
2025
·
IF 5.3
Yupeng Tian,Yujia Liu,Shoutao Ma,Wei Xu,Chenyang Zhao,Bing Sun
This study introduces a heart-like micromixer reactor and Au/TS-1 catalyst to address the dual challenges of safety and efficiency in gas-phase propylene epoxidation using H 2 and O 2 . Conventional methods face inherent explosion risks and rapid catalyst deactivation due to sintering and coking. The microreactor architecture achieves over 99% flame-quenching efficiency via sub-millisecond radical suppression and enhanced heat transfer, enabling safe operation with minimal inert gas dilution (N 2 < 70 vol%). Coupled with alkali-promoted Au/TS-1 catalysts, the system sustains > 90 % propylene oxide (PO) selectivity for 500 h, outperforming static mixers where activity halved within 100 h. This work pioneers a reactor-catalyst co-design strategy, decoupling safety constraints from reaction efficiency, and establishes a scalable platform for sustainable PO synthesis. Besides, the critical gaps in industrial-scale implementation of explosive gas-phase reactions is bridged.
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APPLIED CATALYSIS A-GENERAL
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2024
·
IF 4.7
Chenyang Zhao,Yujia Liu,Yupeng Tian,Yahui Li,Junjie Feng,Wei Xu,Ning Shi,Zhe Yang,Bing Sun
Direct epoxidation of propylene (C 3 H 6 ) with hydrogen (H 2 ) and oxygen (O 2 ) over Au/TS-1 catalyst was promising way for the synthesis of propylene oxide (PO). However, high selectivity of PO (>95 %) and conversion of C 3 H 6 (>5 %) cannot be achieved at the same time. The industrialization process was severely restricted. In this paper, Au/TS-1 catalysts were synthesized by deposition precipitation method with alkali metal promoter. And alkaline gases and silane coupling post-treatment were performed to promote the catalytic activity. The prepared samples exhibited a much better C 3 H 6 conversion (6.5 %) and PO selectivity (95.1 %) compared with general catalyst using normal synthetic technology. Cs 2 CO 3 was beneficial to increasing Au nanoparticles uptake efficiency. Both NH 3 and triethoxyvinylsilane post-treatment were good for smaller and more uniform loading of Au nanoparticles. The decreasing in surface hydroxyl density effectively alleviated the occurrence of PO ring opening isomerization. The increased hydrophobicity of TS-1 surface was conducive to the rapid desorption of generated PO and significantly increased PO selectivity. Multiple pretreatment was also favorable for extending the lifetime of Au/TS-1 catalyst.
研究领域:
催化化学
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材料科学
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CHEMICAL ENGINEERING JOURNAL
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2024
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IF 13.3
Wei Du,Zhihua Zhang,Jundi Wang,Nan Song,Xuezhi Duan,Xinggui Zhou
Propylene epoxidation by H 2 and O 2 to propylene oxide (HOPO), as a novel method for PO production, has attracted widespread attention due to its economic and environmental advantages. Acrolein is a notable byproduct arising in HOPO reaction over Au/TS-1 catalyst, and is traditionally thought to be exclusively formed on Au site through propylene oxidation. However, on the intraporous and external surface Au sites of Au-Ti catalysts, the HOPO reaction have been shown to proceed by different mechanisms, yet the effect of active sites distribution on acrolein formation is far from being understood. Herein, we found that the reaction orders in acrolein formation on Au/TS-1 catalyst (H 2 , 0.19; O 2 , 0.44; C 3 H 6 , 0.44) relative to Au/TS-1 with blocked pores (Au/TS-1-B) catalyst (H 2 , −0.36; O 2 , 0.61; C 3 H 6 , 0.52) were quite different, suggesting a variation in the reaction pathway on the catalysts with different Au locations. Moreover, it is found that PO can be converted to acrolein by O 2 on TS-1 zeolite, which is absent on TS-1-B zeolite without micropores. Consequently, acrolein formation on Au/TS-1 catalyst can proceed through two parallel pathways: propylene hydro-oxidation on Au site, and PO conversion by O 2 inside micropores. Furthermore, by designing and preparing the Au/TS-1 catalysts with different structures, the Au locations are closely related to acrolein formation mechanism and kinetic behaviors. This work provides kinetic insights into the acrolein formation pathways in the HOPO reaction on Au/TS-1 catalyst, and is helpful to the rational design and preparation of efficient catalysts with high selectivity.
研究领域:
催化化学
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材料科学
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环境化学
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Nano Research
·
2023
·Vol. 16
·期 5
·6278-6289
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IF 9.9
Xu Jialun,Zhang Zhihua,Yu Daiyi,Du Wei,Song Nan,Duan Xuezhi,Zhou Xinggui
The catalytic performances over propylene epoxidation with H 2 and O 2 (HOPO process) are significantly affected by the properties (e.g., surface properties, Ti coordination, and morphology) of titanosilicate zeolite. Introducing urea into zeolite synthesis is a simple and convenient method to modify these properties of titanosilicate zeolite. Uncalcined pore-blocked titanium silicalite-1 (TS-1, i.e., TS-1-B) with the lower urea dosage possesses more defective structure and unsaturated coordinated Ti sites verified by 29 Si nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) analysis, which results in a high initial activity and hydrogen efficiency; while the high surface acidity generated by these Ti species leads to a continuous decrease in the activity and the propylene oxide (PO) selectivity during the reaction. As the amount of urea gradually increases, the TS-1-B samples present the reduced surface defects and defective and unsaturated Ti species. Specially, TS-1-B-0.30U presents the weaker PO adsorption on PO-diffusion reflectance infrared Fourier transform spectra (DRIFTS), and thus results in the high stable PO formation rate and selectivity over its Au catalyst. Furthermore, a flat-plate-like shape with a shorter thickness of 100 nm along the b-axis direction is observed on the urea-modified TS-1. Compared with the conventional ellipsoidal TS-1 with crystal sizes of 200 and 500 nm, the flat-plate-like TS-1-0.30U displays the less surface defects, unsaturated Ti species, and the weaker Lewis acid, which is favorable for the desorption and intracrystalline diffusion of PO, thus reduces the occurrence of side reactions for the improved selectivity and stability. This work may provide a reference for developing titanium-containing materials with high activity and stability over HOPO reaction.
研究领域:
催化化学
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材料科学
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Catalysts
·
2026
·Vol. 16
·期 5
·417
·
IF 4.5
Ziyan Mi,Huayun Long,Yuhua Jia,Yue Ma,Cuilan Miao,Yan Xie,Xiaomei Zhu,Jiahui Huang
Developing effective catalysts for the epoxidation of propylene with H2and O2holds significant scientific and industrial significance. This study synthesized a series of Au/TS-1 catalysts modified with alkali metals (Na+, Cs+) and carefully examined their impact on gas-phase propylene epoxidation, with particular attention to the role of anions. The optimal Au–CsC(1:10)/TS-1 catalyst (Cs2CO3modified, Au/Cs molar ratio = 1:10) achieves a propylene conversion of 16.8%, a PO selectivity of 88.5%, an H2efficiency of 40.8%, a record PO formation rate of 383.9 gpo·kgcat−1·h−1, and unprecedented long term stability (>380 h without deactivation). To the best of our knowledge, no previous study has simultaneously achieved such balanced and outstanding performance across all these key indicators. Comprehensive characterization reveals that Cs+modification suppresses side reactions and coke formation, increases microporosity, tunes surface acid–base properties and hydrophobicity, restricts Au particle size, and stabilizes both Au0and tetra coordinated Ti sites, thereby inhibiting H2O2decomposition and PO isomerization while greatly enhancing reaction efficiency. This holistic advancement represents a significant leap forward for Au based catalysts in gas phase propylene epoxidation, offering both a theoretical foundation and practical guidance for the development of high performance epoxidation catalysts.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2024
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IF 5.8
Haihan Huang,Jie Zheng,Kaiyue Wu,Jian Lin,Xin Lin,Quan Yao,Qianyu Fan,Dechao Wang,Yuanbo Huang,Jianchun Jiang,Zhifeng Zheng
Catalytic pyrolysis technology is one of the most environmental and efficient approach in converting biomass waste into high-value chemicals and fuels. In this study, the ex-situ catalytic pyrolysis of cellulose to produce furans and olefins was reported using various metal-loaded TS-1 as catalysts. The experimental results showed that the Au/TS-1 exhibited an exceptional catalytic activity in the production of furans and olefins, achieving a selectivity of 49.17 % and 40.65 %, respectively. Ni/TS-1 effectively promoted the formation of ethylene, yielding a selectivity of 97.49 % and a yield of 6.11 C-mol%. Under the optimized conditions: pyrolysis temperature of 550 ℃, catalytic temperature of 600 ℃, and catalyst to cellulose mass ratio of 20:1, the Au/TS-1 catalyst achieved a furans selectivity of 41.91 % with a yield of 11.94 C-mol%, while olefins selectivity and yield were 49.84 % and 18.99 C-mol%, respectively. At this condition, Au/TS-1 still has excellent catalytic activity after 10 cycles and has good catalytic effect towards different biomass feedstocks. Furthermore, the possible mechanism to produce furans and olefins was revealed. This research offers valuable insights for guiding the directed conversion of biomass into value-added chemicals, paving the way for a more sustainable future.
研究领域:
化学工程
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催化
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生物质转化
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可再生能源
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