APPLIED SURFACE SCIENCE
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2022
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IF 7.392
Minhua Zhang,Haipeng Yu,Yuzhe Sun,Yingzhe Yu,Yifei Chen,Lingtao Wang
Cobalt carbide (Co 2 C) has been discovered as the promising active phase for Fischer–Tropsch to olefins (FTO) process and higher alcohols synthesis (HAS) from syngas, in the form of nanoprisms and nanospheres, respectively. However, CO 2 formation is inevitable on Co 2 C catalysts, especially in FTO process. So far, the mechanism of CO 2 formation on Co 2 C surfaces is less understood. This work provides fundamental insights into CO 2 formation on Co 2 C nanospheres and nanoprisms through computational and experimental study. DFT calculations demonstrate that: Co 2 C (1 0 1) and (0 2 0) surfaces exposed on Co 2 C nanoprisms are basically not active for water gas shift (WGS) reactions but the introduction of Na greatly promotes CO 2 formation. CO 2 is less favored on Co 2 C(1 1 1) surface which is dominant on Co 2 C nanospheres, however, the reverse WGS activities can be promoted with Na addition. The experimental results confirmed removing Na from Co 2 C can efficiently suppress WGS activity, thus reducing CO 2 selectivity while the selectivity of light olefins retained. Though previous studies focused on Na addition to promote the yield of light olefins, our work indicates that Na also promotes undesired CO2 formation. Our results suggest that Na is crucial for active phase formation but not necessarily beneficial during the CO hydrogenation reactions.
研究领域:
化学工程
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催化科学
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2023
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IF 5.2
Fei Zhong,Chunlin Chen,Daiyu Zhang,Rui Yang,Xusong Huang,Kai Yang,Haoqing Qin,Xulin Yang
Polyaniline (PANI), a polymer with a high nitrogen content, has been shown to have good flame retardant properties. Here, we significantly improved the self-carbon formation ability of PANI at high temperature by doping with phytic acid (PA). Meanwhile, a new organic-metal ion flame retardant (DPANI/PA@Cu) was obtained by introducing Cu 2+ with catalytic carbon formation property into PANI/PA using the complexation between transition metal ions and PA. Surprisingly, the introduction of metal ions was also able to trigger the formation of dendritic structure of PANI (DPANI), which is important for its dispersion in resin matrix and strengthening effect on the coating. The test results demonstrated that the composite coating with 5% content of DPANI/PA@Cu had the lowest back-side temperature (174.9 ℃), the highest expansion height (18.5 mm) and the lowest smoke density class (45.3%). In addition, the DPANI/PA@Cu 5% /EP composite coating retained the maximum amount of residual carbon (29.7%), which was mainly related to the synergistic catalytic effect of PA and Cu 2+ . Ultimately, the retained PANI residual carbon and CuO nanoparticles diffused in the char layer acted as interceptors for the external flame and heat.
研究领域:
材料科学
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化学工程
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高分子科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
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2025
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IF 9.5
Yunshuo Wu,Yuxin Sun,Xuanhao Wu,Haiqiang Wang,Lianzhou Wang,Zhongbiao Wu
Industrial nitrous oxide (N2O) emissions with high concentrations pose a significant challenge to climate change, while the oxidative dehydrogenation of propane (ODHP) with N2O presents a promising strategy for N2O valorization. However, the activity-selectivity trade-off and rapid deactivation by coke deposition remain challenges for future applications. Here, we select Pd/TiO2 as model catalysts and design spatially separated redox centers on the rutile phase catalyst (Pd/R-TiO2), which enable parallel adsorption and independent activation of C3H8 on metallic Pd sites and N2O on oxygen vacancies. Besides, it suppresses product overoxidation by reducing reactive oxygen species concentration near C3 intermediates, enhancing C3H6 selectivity while inhibiting enolic intermediate and coke formation to ensure catalyst stability. Hydrogen spillover from Pd sites to TiO2 surface connects the separated redox reactions, completing the catalytic cycle. This work presents a rational strategy for catalyst design in N2O-ODHP, contributing to the sustainable mitigation of non-CO2 greenhouse gases.
研究领域:
催化化学
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环境化学
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化学工程
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绿色化学
✓ 已验证
DOI
高影响因子
ENERGY & FUELS
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2023
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IF 5.3
Haifeng Tian,Zhiyu Chen,Xing Yang,Peng Gao,Chunxue Jiao,Fei Zha,Yue Chang,Hongshan Chen
A method for the direct synthesis of hierarchical zeolites was developed by converting precursors of zeolites and mesoporous copolymers into homogeneous gels using conventional block copolymers as scaffolds. In this method, hydrothermal synthesis is accomplished on a steam-assisted basis, and the dry gel leaves the system free of the liquid water phase, which successfully avoids phase separation between the soft stencil and the solid silica phase. The catalytic performance of hierarchical zeolites was evaluated on a fixed-bed reactor for the methanol-to-aromatics reaction. The hierarchical structure greatly enhances the catalytic activity of the probe reaction due to the increased outer surface, decreased coke formation, and diffusion resistance in the microporous network. The selectivity of BTX reached 65.8%, and there was no significant deactivation after a reaction of 107 h. The transition state and energy barrier for methanol to aromatics were obtained by the minimum energy search of the LST/QST transition state.
研究领域:
化学工程
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催化
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Applications in Energy and Combustion Science
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2025
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IF 6
Zhongyue Zhou,Haoran Liu,Xinghua Liu,Chih-Hao Chin
Coke deposition and catalyst deactivation represent significant challenges in catalytic research, yet the mechanisms underlying their formation remain inadequately understood. Herein, we employed the HZSM-5 catalyzed conversion of furfural as a model reaction and, using a newly developed online high-resolution mass spectrometry (HRMS) technique, directly detected a broad spectrum of oxygenated polycyclic aromatic hydrocarbons (OPAHs) under reaction conditions. Solid-state NMR further revealed the functional group architectures of OPAH side chains in condensed-phase coke, while density functional theory (DFT) calculations elucidated plausible formation and transformation pathways. These complementary approaches establish that highly active OPAHs serve as crucial intermediates in the coke deposition process. We propose a novel mechanism in which light OPAHs, orginating from small-molecule products, undergo rapid polymerization at the active sites to yield larger polycyclic aromatic hydrocarbons, traditionally classified as coke. This newly identified mechanism highlights the unexpectedly rapid coking during the catalytic pyrolysis of biomass, and underscores the significant role of OPAHs in catalyst deactivation. By providing molecular-level insights into coke growth, this study lays a foundation for strategies to suppress coke formation, thereby improving the efficiency and sustainability of catalytic conversion technologies for biomass utilization.
研究领域:
催化化学
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生物质能源
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石油化学
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分析化学
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理论化学
✓ 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）