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Low Temperature Oxidative Dehydrogenation of Ethane to Ethylene Catalyzed by Nano-sized NiO

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催化学报 2003年第6期24卷 403-404页

作者： WU Ying CHEN Tong CAO Xiaodong weng weizheng WAN Huilin State Key Laboratory for Physical Chemistry of Solid Surfaces Department of Chemistry and Institute of Physical ChemistryXiamen 361005FujianChina

The selective oxidation of alkanes into their corresponding olefins has attracted great interest in recent years. Ethane is the second major component of natural gas. The industrial production of ethylene from light alkanes such as ethane uses thermal pyrolysis by high-temperature steam, which is costly in energy. Many attempts have been made to replace this process by the catalytic oxidative dehydrogenation of ethane (ODE). Most catalysts for the ODE reaction are large-sized materials, and the reaction temperatures are high. For example, the C_2H_4 yield is 18% at 660 ℃ over Sm_2O_3, 19.9/5 at 650 ℃ over Sr_(1.0)La_(1.0)Nd_(1.0)O_x, and 26.1% at 660 ℃ over LaOF. In previous studies, it was found that unsupported large-sized nickel oxide is an attractive catalyst for the ODE reaction and requires only a lower reaction temperature. C_2H_4 yield could reach 13% at 400 ℃ (shown in Table 1). Here we report on the low temperature performance of nano-sized nickel oxide catalysts for the ODE reaction.

关键词：低温氧化脱氢乙烷脱氢反应乙烯氧化镍 NiO 纳米催化剂溶胶-凝胶乙烷基

Oscillations during partial oxidation of methane to synthesis gas over Ru/Al_2O_3 catalyst

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Journal of Natural Gas Chemistry 2009年第3期18卷 300-305页

作者： Meiliu Wang weizheng weng Haozhuan Zheng Xiaodong Yi Chuanjing Huang Huilin Wan State Key Laboratory of Physical Chemistry of Solid Surfaces National Engineering Laboratory for Green Chemical Productions of Alcohols Ethers and Esters and Department of Chemistry College of Chemistry and Chemical Engineering Xiamen UniversiO Xiamen 361005 Fujian China

Oscillations in temperatures of catalyst bed as well as concentrations of gas phase species at the exit of reactor were observed during the partial oxidation of methane to synthesis gas over Ru/Al2O3 in the temperature range of 600 to 850℃. XRD, H2-TPR and in situ Raman techniques was used to characterize the catalyst. Two types of ruthenium species, i.e. the ruthenium species weakly interacted with Al2O3 and that strongly interacted with the support, were identified by H2-TPR experiment. These species are responsible for two types of oscillation profiles observed during the reaction. The oscillations were the result of these ruthenium species switching cyclically between the oxidized state and the reduced state under the reaction condition. These cyclic transformations, in turn, were the result of temperature variations caused by the varying levels of the strongly exothermic CH4 combustion and the highly endothermic CH4 reforming （with H2O and CO2） reactions （or the less exothermic direct partial oxidation of methane to CO and H2）, which were favored by the oxidized and the metallic sites, respectively. The major pathway of synthesis gas formation over the catalyst was via the combustion-reforming mechanism.

关键词： Ru/Al2O3 methane partial oxidation synthesis gas oscillation

In-Situ FT-IR Investigation Methane to Syngas over of Partial Oxidation of Rh/SiO2 Catalyst

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Journal of Natural Gas Chemistry 2007年第3期16卷 316-321页

作者： Tinghua Wu Dongmin Lin Ying Wu Xiaoping Zhou Qiangu Yan weizheng weng Huilin Wan Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces Institute of Physical Chemistry Zhejiang Normal University Jinhua 321004 Zhejiang China State Key Laboratory for Physical Chemistry of Solid Surfaces Xiamen University Xiamen 361005 Fujian China Center for Advanced Vehicular Systems Box 5405 Mississippi State University Starkville MS39762 USA

Partial oxidation of methane to syngas （POM） over Rh/SiO2 catalyst was investigated using in-situ FT-IR. When methane interacted with 1.0wt%Rh/SiO2 catalyst, it was dissociated to adsorbed hydrogen and CHx species. The adsorbed hydrogen atoms were transferred to SiO2 surface by ＂spill-over＂ and reacted with lattice oxygen to form surface -OH species. POM mechanism was investigated over Rh/SiO2 catalyst using in-situ FT-IR. It was found that CO2 was formed before CO could be detected when CH4 and O2 were introduced over the preoxidized Rh/SiO2 catalyst, whereas CO was detected before CO2 was formed over the prereduced Rh/SiO2 catalyst.

关键词： partial oxidation syngas Rh/SiO2 catalyst in-situ FT-IR

基于轻量化YOLOv7-tiny的船舶目标检测算法

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大连海事大学学报 2024年第2期50卷 31-40页

作者：丘锐聪周海峰陈颖张兴杰黄金满翁卫征集美大学轮机工程学院福建厦门361021 集美大学福建省船舶与海洋工程重点实验室福建厦门361021 集美大学航海学院福建厦门361021 厦门安麦信自动化科技有限公司福建厦门361000 厦门三丰鑫科技有限公司福建厦门361001

为解决船舶目标检测算法参数量与计算量大,以及受内河环境下近岸复杂背景影响和船舶相互遮挡导致船舶检测困难的问题,基于YOLOv7-tiny做出改进,提出MED-YOLO船舶目标检测轻量化算法。首先,使用MobileNetV3网络作为主干特征提取网络,极... 详细信息

为解决船舶目标检测算法参数量与计算量大,以及受内河环境下近岸复杂背景影响和船舶相互遮挡导致船舶检测困难的问题,基于YOLOv7-tiny做出改进,提出MED-YOLO船舶目标检测轻量化算法。首先,使用MobileNetV3网络作为主干特征提取网络,极大地降低了模型计算成本;其次,将EMA注意力模块引入颈部网络,构建EMA-ELAN模块,增强网络多维度感知和多尺度特征提取能力;然后,选用将尺度感知、空间感知和任务感知三合一的Dyhead作为改进模型的检测头部,以获得更强的特征表达能力;最后,使用具有动态非单调聚焦机制的WIoU作为模型边界框损失函数,提高模型应对船舶遮挡的能力,提升检测性能。实验结果表明,MED-YOLO相较YOLOv7-tiny在参数量与计算量方面分别减少39.8%和55.0%,精度与mAP@0.5分别提高了1.4%和1.0%,达到98.3%和98.9%,在实现轻量化的同时具有更好的检测性能,满足了计算资源受限环境下的部署需求,具有一定的工程实际意义。

关键词： YOLOv7-tiny 目标检测轻量化注意力机制损失函数

Additive effects of alkaline-earth metals and nickel on the performance of Co/γ-Al_2O_3 in methane catalytic partial oxidation

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Journal of Natural Gas Chemistry 2011年第2期20卷 135-139页

作者： Changlin Yu weizheng weng Qing Shu Xiangjie Meng Bin Zhang Xirong Chen Xiaochun Zhou School of Materials and Chemical Engineering Jiangxi University of Science and Technology Ganzhou 341000 Jiangxi China State Key Laboratory of Physical Chemistry of Solid Surfaces Department of Chemistry Xiamen University Xiamen 361005 Fujian China

Nano-sized γ-alumina （γ-Al2O3） was first prepared by a precipitation method. Then, active component of cobalt and a series of alkaline- earth metal promoters or nickel （Ni） with different contents were loaded on the γ-Al2O3 support. The catalysts were characterized by N2 adsorption-desorption, X-ray diffraction （XRD） and thermogravimetry analysis （TGA）. The activity and selectivity of the catalysts in catalytic partial oxidation （CPO） of methane have been compared with Co/γ-Al2O3, and it is found that the catalytic activity, selectivity, and stability are enhanced by the addition of alkaline-earth metals and nickel. The optimal loadings of strontium （Sr） and Ni were 6 and 4 wt%, respectively. This finding will be helpful in designing the trimetallic Co-Ni-Sr/γ-Al2O3 catalysts with high performance in CPO of methane

关键词： alkaline-earth metal cobalt-based catalyst γ-alumina catalytic partial oxidation methane

In situ time-resolved FTIR investigation on the reaction mechanism of partial oxidation of methane to syngas over supported Rh and Ru catalysts

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Chinese Science Bulletin 2000年第24期45卷 2236-2240页

作者： weng weizheng CHEN Mingshu YAN Qiangu WU Tinghua CHAO Zisheng LIAO Yuanyan WAN Huilin Department of Chemistry State Key Laboratory for Physical Chemistry of Solid Surfacesand Institute of Physical ChemistryXiamen UniversityXiamen 361005China Department of Chemistry Zhejiang Normal UniversityJinhua 321004China

In situ time-resolved FTIR spectroscopy was used to study the reaction mechanism of partial oxidation of methane (POM) to synthesis gas and the reaction of CH4/O2/He (2/1/45, molar ratio) gas mixture with adsorbed CO species over Rh/SiO2, Ru/γ-Al2O3 and Ru/SiO2 catalysts at 500-600℃. It was found that CO is the primary product of POM reaction over reduced and working state Rh/SiO2 catalysts. Direct oxidation of CH4 is the main pathway of synthesis gas formation over Rh/SiO2 catalyst. CO2 is the primary product of POM over Ru/γ-Al2O3 and Ru/SiO2 catalysts. The dominant reaction pathway for synthesis gas formation over Ru/γ-Al2O3 catalyst is via the reforming reactions of CH4 with CO2 and H2O. For the POM reaction over Rh/SiO2 and Ru/γ-Al2O3 catalysts, consecutive oxidation of surface CO species is an important pathway of CO2 formation.

关键词： partial oxidation of methane synthesis gas reaction mechanism in situ time-resolved FTIR ruthenium rhodium supported metal catalyst.

XPS,Chemical Trapping, and DRFTIR Study on Mechanism of By-Products Formation in Selective (AMM)Oxidation of Propylene on MoO_3 and γ-Bi_2MoO_6

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Chemical Research in Chinese Universities 1990年第4期6卷 346-353页

作者： weng weizheng, Yan Jiyang, Cai Junxiu, Dai Shenjun,Cao Shoujing, Chen Lingling and Wan Huilin (Department of Chemistry, Xiamen University, Ximen)

XPS and chemical trapping experments with H2, NH3, and CH3I as trapping agents were carried out for studying the adsorption of propylene over MoO3 or r-Bi2MoO6. The results show that the fragmentation of carbon chain takes place during the adsorption of propylene through breaking C -C double bond and C-C bond on Mo2+ and the adjacent lattice oxygen, leading to formation of the oxygen- or nitrogen-containing by-products of C1 and C2 species. Diffuse-Reflection Fourier Transform Infrared (DRFTIR) Spectroscopy was used to study the surface species formed during the chemisorption and reaction of propylene over y-Bi2MoO6 at a lower temperature. The results that C1, C2 adspecies were detected by DRFTIR at 175℃ are consistent with the results of XPS and chemical trapping experiments, whlle the results at 50℃ Grasselli et al.

关键词： Selective (amm)oxidation of propylene Mechanism of by-products formation Chemical trapping DRFTIR

CeO_(2)负载的PdO与Ce_(1‒x)Pd_(x)O_(2‒δ)物种的甲烷催化燃烧性能

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高等学校化学学报 2022年第4期43卷 112-123页

作者：王明智郑燕萍翁维正厦门大学化学化工学院固体表面物理化学国家重点实验室醇醚酯化工清洁生产国家工程实验室厦门361005

通过调控Pd前驱物在CeO_(2)上的沉积方式,分别制备了以PdO和离子态的Ce_(1‒x)Pd_(x)O_(2‒δ)物种为主的Pd/CeO_(2)催化剂,并采用X射线光电子能谱(XPS)和拉曼(Raman)光谱确证了这两种Pd物种的存在.氧气程序升温脱附(O_(2)-TPD)和氢气程... 详细信息

通过调控Pd前驱物在CeO_(2)上的沉积方式,分别制备了以PdO和离子态的Ce_(1‒x)Pd_(x)O_(2‒δ)物种为主的Pd/CeO_(2)催化剂,并采用X射线光电子能谱(XPS)和拉曼(Raman)光谱确证了这两种Pd物种的存在.氧气程序升温脱附(O_(2)-TPD)和氢气程序升温还原(H_(2)-TPR)的表征结果显示,相比于与载体相互作用较弱的PdO物种,与CeO_(2)相互作用较强的Ce_(1‒x)Pd_(x)O_(2‒δ)物种具有更加稳定的Pd—O键.催化剂的甲烷燃烧反应起燃活性测试结果显示,以PdO物种为主的催化剂表现出了良好的低温催化性能,在原料气配比为1%CH_(4)/4%O_(2)-Ar,空速为60000 mL·g^(-1)_(cat)·h^(‒1)的条件下,T_(10)和T_(90)分别为275和367℃,而两种以Ce_(1‒x)Pd_(x)O_(2‒δ)物种为主的催化剂的T_(10)均超过420℃.催化剂的甲烷程序升温还原(CH_(4)-TPR)表征结果表明,在升温过程中只有当PdO或Ce_(1‒x)Pd_(x)O_(2‒δ)物种被CH_(4)还原后,催化活性才开始上升.由于PdO物种的Pd—O键强度较弱,有利于Pd物种上的晶格氧在较低温度下参与CH_(4)的氧化过程.而Ce_(1‒x)Pd_(x)O_(2‒δ)物种的Pd—O键较稳定,且在反应条件下离子态Pd^(2+)与反应体系中氧物种的作用较强,进而抑制了其与CH_(4)的反应,因此反应的起燃温度较高.以γ-Al_(2)O_(3)为载体采用相同的方法制备了Pd/γ-Al_(2)O_(3)催化剂,相关的表征结果进一步证实,与载体相互作用较弱的PdO物种更容易被CH_(4)还原,进而具有较高的催化活性.据此可以认为Pd/CeO_(2)上氧化态的Pd物种被CH_(4)的还原性能是决定其甲烷催化燃烧反应活性的重要因素之一.

关键词：氧化铈钯甲烷催化氧化氧化钯 Ce_(1‒x)Pd_(x)O_(2‒δ) 还原性

Size and support effects for CO oxidation on supported Pd catalysts

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Science China Chemistry 2010年第9期53卷 2047-2056页

作者： WANG ZhaoWen,LI Bin,CHEN MingShu,weng weizheng & WAN HuiLin State Key Laboratory of Physical Chemistry of Solid Surfaces National Engineering Laboratory for Green Chemical Productions of Alcohols-Ethers-Esters Department of Chemistry,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,China State Key Laboratory of Physical Chemistry of Solid Surfaces Xiamen University Xiamen China National Engineering Laboratory for Green Chemical Productions of Alcohols-Ethers-Esters Xiamen University Xiamen China Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen China

Supporting Pd catalysts characterized significant different size distribution were obtained using PdCl2,[Pd(NH3)4](NO3)2 and Pd(acac)2 as ***-resolution transmission electron microscopy(TEM),X-ray diffraction(XRD),in-situ Fourier transform infrared spectroscopy(FTIR) and Raman spectroscopy were used to examine the dispersion of *** performance measurements show that the activities for CO oxidation increase as the Pd particle size decreases and the O2/CO ratio *** activities under oxygen rich conditions are significantly higher than those at near the stoichiometric *** on TiO2 prepared by the Pd(acac)2 precursor is highly dispersed,leading to a considerable activity for CO oxidation at near room *** oxidation on the 1 wt% Pd/TiO2 and under an O2/CO ratio of 1 characterized an apparent activation energy of 36.7 kJ/mol,which is closed to those reported for CO oxidation on the supported Au *** present work demonstrates a high catalytic activity of highly dispersed noble metals,and suggests a promising approach of using noble metals as catalysts with exceeding high efficiency.

关键词： noble metals supported palladium CO oxidation size effect support effect