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Effects of soil moisture and temperature on CH_4 oxidation and N_2O emission of forest soil 被引量:2
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作者 张秀君 徐慧 陈冠雄 《Journal of Forestry Research》 CAS CSCD 2000年第3期203-206,共4页
Soil samples were taken from depth of 0-12cm in the virgin broad- leaved/Korean pine mixed forest in Changbai Mountain in April, 2000. 20 μL·L-1 and 200 μL·L-1 CH4 and N2O concentration were supplied for a... Soil samples were taken from depth of 0-12cm in the virgin broad- leaved/Korean pine mixed forest in Changbai Mountain in April, 2000. 20 μL·L-1 and 200 μL·L-1 CH4 and N2O concentration were supplied for analysis. Laboratory study on CH4 oxidation and N2O emission in forest soil showed that fresh soil sample could oxidize atmospheric methane and product N2O. Air-dried soil sample could not oxidize atmospheric methane, but could produCt N2O. However, it could oxidize the supplied methane quickly when its concentration was higher than 20 μL·L-1. The oxidation rate of methane was increased with its initial concentration. An addition of water to dry soil caused large pulse of N2O emissions within 2 hours. There were curvilinear correlations between N2O emission and temperature (r2=0.706, p <0.05), and between N2O emission andtwater content (r2=0.2968. p <0.05). These suggested temperature and water content were important factors controlling N2O emission. The correlation between CH4 oxidization and temperature was also found while CH4 was supplied 200 μL·L-1 (r2 =0.3573, p<0.05). Temperature was an important f8Ctor controlling CH4 oxidation. However, when 20 μL·L-1 CH4 was supplied, there was no correlation among CH4 oxidization, N2O emission, temperature and water content. 展开更多
关键词 Air-dried soil Fresh forest soil CH_4 oxidation N_2O emission
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Role of methoxy and C_(α)-based substituents in electrochemical oxidation mechanisms and bond cleavage selectivity of β-O-4 lignin model compounds 被引量:1
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作者 Yang Zhou Qiang Zeng +3 位作者 Hongyan He Kejia Wu Fuqiao Liu Xuehui Li 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第1期114-125,共12页
In order to better understand the specific substituent effects on the electrochemical oxidation process of β-O-4 bond, a series of methoxyphenyl type β-O-4 dimer model compounds with different localized methoxyl gro... In order to better understand the specific substituent effects on the electrochemical oxidation process of β-O-4 bond, a series of methoxyphenyl type β-O-4 dimer model compounds with different localized methoxyl groups, including 2-(2-methoxyphenoxy)-1-phenylethanone, 2-(2-methoxyphenoxy)-1-phenylethanol, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanol, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanol have been selected and their electrochemical properties have been studied experimentally by cyclic voltammetry, and FT-IR spectroelectrochemistry. Combining with electrolysis products distribution analysis and density functional theory calculations, oxidation mechanisms of all six model dimers have been explored. In particular, a total effect from substituents of both para-methoxy(on the aryl ring closing to Cα) and Cα-OH on the oxidation mechanisms has been clearly observed, showing a significant selectivity on the Cα-Cβbond cleavage induced by electrochemical oxidations. 展开更多
关键词 Lignin model compounds β-O-4 dimers Electrochemical oxidation oxidation mechanisms Substituent effect
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Study on the oxidation mechanism of Al-SiC composite at elevated temperature
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作者 Jishuo Han Yong Li +3 位作者 Chenhong Ma Qingyao Zheng Xiuhua Zhang Xiaofang Wu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第9期2077-2087,共11页
Resin-bonded Al-SiC composite was sintered at 1100,1300,and 1500℃ in the air,the oxidation mechanism was investigated.The reaction models were also established.The oxidation resistance of the Al-SiC composite was sig... Resin-bonded Al-SiC composite was sintered at 1100,1300,and 1500℃ in the air,the oxidation mechanism was investigated.The reaction models were also established.The oxidation resistance of the Al-SiC composite was significantly enhanced with temperature increase.SiC in the exterior of the composite was partially oxidized slightly,while the transformation of metastable Al_(4)C_(3) to stable Al_(4)SiC_(4) existed in the interior.At 1100℃,Al in the interior reacted with residual C to form Al_(4)C_(3).With increasing to 1300℃,high temperature and low oxygen partial pressure lead to active oxidation of SiC,and internal gas composition transforms to Al_(2)O(g)+CO(g)+SiO(g)as the reaction proceeds.After Al_(4)C_(3) is formed,CO(g)and SiO(g)are continuously deposited on its surface,transforming to Al_(4)SiC_(4).At 1500℃,a dense layer consisting of SiC and Al_(4)SiC_(4) whiskers is formed which cuts off the diffusion channel of oxygen.The active oxidation of SiC is accelerated,enabling more gas to participate in the synthesis of Al_(4)SiC_(4),eventually forming hexagonal lamellar Al_(4)SiC_(4) with mutual accumulation between SiC particles.Introducing Al enhances the oxidation resistance of SiC.In addition,the in situ generated non-oxide is uniformly dispersed on a micro-scale and bonds SiC stably. 展开更多
关键词 Al-SiC composite kiln furniture Al_(4)SiC_(4) Al_(4)C_(3) oxidation mechanism
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Oxidation behavior of FeV_(2)O_(4)and FeCr_(2)O_(4)particles in the air:Nonisothermal kinetic and reaction mechanism
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作者 Junyi Xiang Xi Lu +6 位作者 Luwei Bai Hongru Rao Sheng Liu Qingyun Huang Shengqin Zhang Guishang Pei Xuewei Lü 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第8期1839-1848,共10页
High-temperature oxidation behavior of ferrovanadium(FeV_(2)O_(4))and ferrochrome(FeCr_(2)O_(4))spinels is crucial for the application of spinel as an energy material,as well as for the clean usage of high-chromium va... High-temperature oxidation behavior of ferrovanadium(FeV_(2)O_(4))and ferrochrome(FeCr_(2)O_(4))spinels is crucial for the application of spinel as an energy material,as well as for the clean usage of high-chromium vanadium slag.Herein,the nonisothermal oxidation behavior of FeV_(2)O_(4)and FeCr_(2)O_(4)prepared by high-temperature solid-state reaction was examined by thermogravimetry and X-ray diffraction(XRD)at heating rates of 5,10,and 15 K/min.The apparent activation energy was determined by the Kissinger-Akahira-Sunose(KAS)method,whereas the mechanism function was elucidated by the Malek method.Moreover,in-situ XRD was conducted to deduce the phase transformation of the oxidation mechanism for FeV_(2)O_(4)and FeCr_(2)O_(4).The results reveal a gradual increase in the overall apparent activation energies for FeV_(2)O_(4)and FeCr_(2)O_(4)during oxidation.Four stages of the oxidation process are observed based on the oxidation conversion rate of each compound.The oxidation mechanisms of FeV_(2)O_(4)and FeCr_(2)O_(4)are complex and have distinct mechanisms.In particular,the chemical reaction controls the entire oxidation process for FeV_(2)O_(4),whereas that for FeCr_(2)O_(4)transitions from a three-dimensional diffusion model to a chemical reaction model.According to the in-situ XRD results,numerous intermediate products are observed during the oxidation process of both compounds,eventually resulting in the final products FeVO_(4)and V2O_(5)for FeV_(2)O_(4)and Fe_(2)O_(3)and Cr_(2)O_(3)for FeCr_(2)O_(4),respectively. 展开更多
关键词 FeV_(2)O_(4) FeCr_(2)O_(4) oxidation nonisothermal kinetics mechanism
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Facile Surface Engineering of NiCo_(2)O_(4) to Boost Propane Oxidation Activity
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作者 Yang Jialei Wang Fengyi +7 位作者 Lei Yang Zhang Mingchao Sun Shiqiang Xu Wenfan Ke Jiaxiang Wu Haojie Li Xingyun Qi Jian 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS CSCD 2024年第1期19-26,共8页
Spinel oxide(NiCo_(2)O_(4))has demonstrated great potential to replace noble metal catalysts for the oxidation reaction of air pollutants.To further boost the oxidation ability of such catalysts,in this study,a facile... Spinel oxide(NiCo_(2)O_(4))has demonstrated great potential to replace noble metal catalysts for the oxidation reaction of air pollutants.To further boost the oxidation ability of such catalysts,in this study,a facile surface-engineering strategy wherein NiCo_(2)O_(4) was treated with different alkali solvents was developed.The obtained catalyst(NiCo_(2)O_(4)-OH)showed a higher surface alkalinity and more surface defects compared to the pristine spinel oxide,including enhanced structural distortion as well as promoted oxygen vacancies.The propane oxidation ability of NiCo_(2)O_(4)-OH was greatly enhanced,with a propane conversion rate that was approximately 6.4 times higher than that of pristine NiCo_(2)O_(4) at a reaction temperature 193℃.This work sets a valuable paradigm for the surface modulation of spinel oxide via alkali treatment to ensure a high-performance oxidation catalyst. 展开更多
关键词 NiCo_(2)O_(4) surface defects alkali treatment propane oxidation
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Regulating the oxidation state of Pd to enhance the selective hydrogenation for 5-hydroxymethylfurfural
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作者 Xin Li Yue Ma +3 位作者 Xuning Wang Jianguo Wu Dong Cao Daojian Cheng 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第8期60-68,共9页
The highly selective hydrogenation of 5-hydroxymethylfurfural to 2,5-dihydroxymethylfuran is an important reaction in the field of biomass hydrogenation,because it is a bridge between biomass resources and chemical in... The highly selective hydrogenation of 5-hydroxymethylfurfural to 2,5-dihydroxymethylfuran is an important reaction in the field of biomass hydrogenation,because it is a bridge between biomass resources and chemical industry.Here,we precisely constructed carbon nitride supported Pd-based catalysts by a simple impregnation-reduction method.By changing the reduction temperature,catalysts with different oxidation state could be precisely constructed.Moreover,the important correlation between the ratio of Pd^(0)/Pd^(2+)and catalytic activity is revealed during the selective hydrogenation of HMF.The Pd/g—C_(3)N_(4)—300 catalyst with a Pd^(0)/Pd^(2+)ratio of 3/2 showed the highest catalytic activity,which could get 96.9%5-hydroxymethylfurfural conversion and 90.3%2,5-dihydroxymethylfuran selectivity.Further density functional theory calculation revealed that the synergistic effect between Pd0and Pd2+in Pd/g—C_(3)N_(4)—300 system could boost the adsorption of the substrate and the dissociation of hydrogen.In this work,we highlight the important correlation between metal oxidation state and catalytic activity,which provides valuable insights for the rational design of precious metal catalysts for hydrogenation reactions. 展开更多
关键词 Pd/g-C_(3)N_(4) Selective hydrogenation 5-HYDROXYMETHYLFURFURAL 2 5-dihydroxymethylfuran oxidation state
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Sustainable Furfural Biomass Feedstocks Electrooxidation toward Value-Added Furoic Acid with Energy-Saving H_(2) Fuel Production Using Pt-Decorated Co_(3)O_(4) Nanospheres
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作者 Talshyn Begildayeνa Jayaraman Theerthagiri +4 位作者 Seung Jun Lee Ahreum Min Gyeong-Ah Kim Siνakumar Manickam Myong Yong Choi 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第2期350-358,共9页
Here,furfural oxidation was performed to replace the kinetically sluggish O_(2)evolution reaction(OER).Pt-Co_(3)O_(4)nanospheres were developed via pulsed laser ablation in liquid(PLAL)in a single step for the paired ... Here,furfural oxidation was performed to replace the kinetically sluggish O_(2)evolution reaction(OER).Pt-Co_(3)O_(4)nanospheres were developed via pulsed laser ablation in liquid(PLAL)in a single step for the paired electrocatalysis of an H_(2)evolution reaction(HER)and furfural oxidation reaction(FOR).The FOR afforded a high furfural conversion(44.2%)with a major product of 2-furoic acid after a 2-h electrolysis at 1.55 V versus reversible hydrogen electrode in a 1.0-M KOH/50-mM furfural electrolyte.The Pt-Co_(3)O_(4)electrode exhibited a small overpotential of 290 mV at 10 mA cm^(-2).As an anode and cathode in an electrolyzer system,the Pt-Co_(3)O_(4)electrocatalyst required only a small applied cell voltage of~1.83 V to deliver 10 mA cm^(-2),compared with that of the pure water electrolyzer(OER||HER,~1.99 V).This study simultaneously realized the integrated production of energy-saving H_(2)fuel at the cathode and 2-furoic acid at the anode. 展开更多
关键词 biomass conversion electrochemical furfural oxidation overall water splitting Pt-Co_(3)O_(4)electrocatalyst pulsed laser ablation in liquid
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Effect of the addition of rare earths on the activity of alumina supported copper cobaltite in CO oxidation, CH_4 oxidationand NO decomposition 被引量:6
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作者 B.Ivanov I.Spassova +2 位作者 M.Milanova G.Tyuliev M.Khristova 《Journal of Rare Earths》 SCIE EI CAS CSCD 2015年第4期382-390,共9页
The effect of the addition of small amounts of rare earths (Ln=La, Ce, Nd and Gd) to alumina supported copper-cobalt spinel oxide on the catalysts efficiency in CO and CH4 oxidation and in NO decomposition was inves... The effect of the addition of small amounts of rare earths (Ln=La, Ce, Nd and Gd) to alumina supported copper-cobalt spinel oxide on the catalysts efficiency in CO and CH4 oxidation and in NO decomposition was investigated. Samples of Ln/CuCo/AI catalyst were prepared and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic absorption spectroscopy (AAS), scanning electron mieroscopy-energy dispersive spectroscopy (SEM-EDS), H2-temperature-programmed reduc- tion (H2-TPR), electron paramagnetic resonanee (EPR) spectroscopy and low temperature nitrogen adsorption, The results showed that the addition of rare earths changed the surface state of the alumina supported copper-cobalt spinel catalyst. As a result, partial re- duction of copper species was observed as well as migration of these species between the surface and the bulk. The Ln/CuCo/A1 catalysts behaved differently in oxidation and reduction processes. In oxidation processes where oxide structure was important, Ce/CuCo/A1 and Nd/CuCo/A1 were the most active catalysts. The catalyst Ce/CuCo/AI was the most active in the oxidation reactions because of the availability and favorable surface distribution of the redox couples Cu+/Cu2+ and Ce3+/Ce4+. In NO decompostion, Ln-modified catalysts significantly improved the selectivity of the process to N2. 展开更多
关键词 copper cobaltite NO decomposition CO oxidation CH4 oxidation rare earths
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Study on ceria-modified SnO_2 for CO and CH_4 oxidation 被引量:3
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作者 曾宪荣 张荣斌 +1 位作者 徐香兰 王翔 《Journal of Rare Earths》 SCIE EI CAS CSCD 2012年第10期1013-1019,共7页
Sn-Ce-O binary catalysts with different Sn/Ce molar ratios were prepared with co-precipitation method and applied for CO and CH4 oxidation. The catalysts were characterized by means of Nz-BET, XRD and H2-TPR technique... Sn-Ce-O binary catalysts with different Sn/Ce molar ratios were prepared with co-precipitation method and applied for CO and CH4 oxidation. The catalysts were characterized by means of Nz-BET, XRD and H2-TPR techniques. It was found that for those Sn rich sam- pies such as SnCe91 and SnCe73, Ce cations were doped into the matrix of tetragonal rutile SnO2 to form SnO2-based solid solution. As a consequence, the oxidation activity as well as the thermal stability was significantly improved compared with pure SnO2. In contrast, for Ce rich samples such as SnCel9, SnCe37 and SnCe55, though the thermal stability was improved, the activity was worse than SnO2, due to the presence of much less amount of active oxygen species. Co-precipitation was found to be the best method to prepare Sn-Ce binary catalysts among all of the methods tried in this study. 展开更多
关键词 Sn-Ce mixed oxide catalysts solid solution CH4 combustion CO oxidation rare earths
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Promotional effects of samarium on Co_3O_4 spinel for CO and CH_4 oxidation 被引量:2
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作者 徐香兰 韩红 +3 位作者 刘建军 刘文明 李文龙 王翔 《Journal of Rare Earths》 SCIE EI CAS CSCD 2014年第2期159-169,共11页
A series of CO3O4 spinel catalysts modified by Sm were prepared by co-precipitation method and tested for CH4 and CO oxidation. The addition of a small amount of Sm into Co3O4 led to an improvement in the catalytic ac... A series of CO3O4 spinel catalysts modified by Sm were prepared by co-precipitation method and tested for CH4 and CO oxidation. The addition of a small amount of Sm into Co3O4 led to an improvement in the catalytic activity for both reactions. Co0.98Sm0. 02 and Co0.95Sm0.05, the two samples with Co/Sm molar ratio of 0.98/0.02 and 0.95/0.05 in sequence, showed the similar and the highest activity for CH4 oxidation, with CH4 complete conversion at 450 ℃. In contrast, Coo.90Smo l0 was the most active sample for CO oxidation, with CO complete conversion at 120 ℃. The catalysts were characterized by techniques of N2 adsor- tion-desorption with Brunauer-Emmett-Teller technique (N2-BET), X-ray powder diffraction (XRD), thermal gravity analy- sis-differential scanning calorimetry (TGA-DSC), Hz temperature programmed reduction (H2-TPR) and X-ray photoelectron spec- troscopy analysis (XPS). Compared with pure Co3O4, for CO1-xSmx catalysts with 0.02≤x≤0.10, the addition of a small amount of Sm resulted in the formation of spinel Co3O4 and amorphous SmCoO3, hence increasing the number of Co3+ and the active surface oxygen species, which was responsible for the improvement of the activity. C00.95Sm0.05 catalyst showed not only high thermal stability and activity but also good reaction durability in the presence of 5% water vapor for CH4 oxidation. 展开更多
关键词 CO3O4 SmCoO3 CO and CH4 oxidation water vapor effect rare earths
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Vicious cycle of lipid peroxidation and iron accumulation in neurodegeneration 被引量:5
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作者 Instituto de Salud Carlos III Irene Villalón-García +9 位作者 Suleva Povea-Cabello MónicaÁlvarez-Córdoba Marta Talaverón-Rey Juan MSuárez-Rivero Alejandra Suárez-Carrillo Manuel Munuera-Cabeza Diana Reche-López Paula Cilleros-Holgado Rocío Piñero-Pérez JoséA.Sánchez-Alcázar 《Neural Regeneration Research》 SCIE CAS CSCD 2023年第6期1196-1202,共7页
Lipid peroxidation and iron accumulation are closely associated with neurodegenerative diseases,such as Alzheimer’s,Parkinson’s,and Huntington’s diseases,or neurodegeneration with brain iron accumulation disorders.... Lipid peroxidation and iron accumulation are closely associated with neurodegenerative diseases,such as Alzheimer’s,Parkinson’s,and Huntington’s diseases,or neurodegeneration with brain iron accumulation disorders.Mitochondrial dysfunction,lipofuscin accumulation,autophagy disruption,and ferroptosis have been implicated as the critical pathomechanisms of lipid peroxidation and iron accumulation in these disorders.Currently,the connection between lipid peroxidation and iron accumulation and the initial cause or consequence in neurodegeneration processes is unclear.In this review,we have compiled the known mechanisms by which lipid peroxidation triggers iron accumulation and lipofuscin formation,and the effect of iron overload on lipid peroxidation and cellular function.The vicious cycle established between both pathological alterations may lead to the development of neurodegeneration.Therefore,the investigation of these mechanisms is essential for exploring therapeutic strategies to restrict neurodegeneration.In addition,we discuss the interplay between lipid peroxidation and iron accumulation in neurodegeneration,particularly in PLA2G6-associated neurodegeneration,a rare neurodegenerative disease with autosomal recessive inheritance,which belongs to the group of neurodegeneration with brain iron accumulation disorders. 展开更多
关键词 4-hidroxynonenal ferroptosis IRON lipid peroxidation LIPOFUSCIN NEURODEGENERATION neurodegeneration with brain iron accumulation oxidative stress PLA2G6-associated neurodegeneration
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2,5-Diformylfuran production by photocatalytic selective oxidation of 5-hydroxymethylfurfural in water using MoS_(2)/CdIn_(2)S_(4) flower-like heterojunctions 被引量:3
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作者 Qian Zhu Yan Zhuang +7 位作者 Hongqing Zhao Peng Zhan Cong Ren Changsheng Su Wenqiang Ren Jiawen Zhang Di Cai Peiyong Qin 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第2期180-191,共12页
The selective oxidation of 5-hydroxymethylfurfural(HMF) into 2,5-diformylfuran(DFF) is an important reaction for renewable biomass building blocks. Compared with thermal catalytic processes, photocatalytic production ... The selective oxidation of 5-hydroxymethylfurfural(HMF) into 2,5-diformylfuran(DFF) is an important reaction for renewable biomass building blocks. Compared with thermal catalytic processes, photocatalytic production of DFF from HMF has attracted tremendous attention. Herein, the MoS_(2)/CdIn_(2)S_(4)(MC)flower-like heterojunctions were prepared and considered as photocatalysts for selective oxidation of HMF into DFF under visible-light irradiation in aqueous solution. Results demonstrated MoS_(2) in MC heterojunction could promote the separation of photoexcited electron-hole pairs, while the amount of MoS_(2) dropping was proved influenced on the photocatalytic performance. 80.93% of DFF selectivity was realized when using 12.5% MC as photocatalyst. In addition, the MC catalyst also showed great potential in transformation of other biomass derived benzyl-and furyl-alcohols. The catalytic mechanism suggested that ·O_(2)^(-) was the decisive active radical for HMF oxidation. Therefore, the MC heterojunction could be applied in photocatalytic conversion of biomass to valuable chemicals under ambient condition. 展开更多
关键词 2 5-Diformylfuran(DFF) Photocatalysis MoS_(2)/CdIn_(2)S_(4)(MC) Selective oxidation Visible light irradiation
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Electrochemical response of MgO/Co_(3)O_(4) oxide layers produced by plasma electrolytic oxidation and post treatment using cobalt nitrate
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作者 Mosab Kaseem Tehseen Zehra +2 位作者 Tassawar Hussain Young Gun Ko Arash Fattah-alhosseini 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第3期1057-1073,共17页
This work looked into the influence of the sealing treatment on the structural feature and electrochemical response of AZ31 Mg alloy coated via plasma electrolytic oxidation(PEO).Here,the inorganic layers produced by ... This work looked into the influence of the sealing treatment on the structural feature and electrochemical response of AZ31 Mg alloy coated via plasma electrolytic oxidation(PEO).Here,the inorganic layers produced by PEO in an alkaline-phosphate electrolyte were subsequently immersed for different periods in cold(60°C)and hot(100°C)aqueous solutions containing either 1 or 3 gr of cobalt nitrate hexahydrate in the presence of hydrogen peroxide as an initiator.The results showed that the sealing treatments in the hot solutions could trigger the hydration reactions of PEO coating which would largely assist the surface incorporation of Co_(3)O_(4)into the coating.In contrast,the sealing in cold solutions led to less compact coatings,which was attributed to the fact the hydration reactions would be restricted at 60°C.A nearly fully sealed coating with a porosity of~0.5%was successfully formed on the sample immersed in the hot solution containing 1 gr of cobalt nitrate hexahydrate.Thus,the electrochemical stability of this fully sealed coating was superior to the other samples as it had the lowest corrosion current density(4.71×10^(-10)A·cm^(-2))and the highest outer layer resistance(3.81×10^(7)Ω·cm^(2)).The composite coatings developed in this study are ideal for applications requiring high electrochemical stability. 展开更多
关键词 AZ31 Mg alloy Plasma electrolytic oxidation Co_(3)O_(4) HYDRATION Corrosion
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Oxidation and Electrical Properties of Cu-Mn_(3)O_(4)Composite Coating Obtained by Electrodeposition on SOFC Interconnects
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作者 吕烨 LUO Shengyun 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2023年第1期72-78,共7页
Cu-Mn_(3)O_(4)composite coating was prepared on the SUS 430 ferritic stainless steel by electrodeposition and then exposed in air at 800℃corresponding to the cathode atmosphere of solid oxide fuel cell(SOFC).A dual-l... Cu-Mn_(3)O_(4)composite coating was prepared on the SUS 430 ferritic stainless steel by electrodeposition and then exposed in air at 800℃corresponding to the cathode atmosphere of solid oxide fuel cell(SOFC).A dual-layer oxide structure mainly comprising an external layer of CuO followed by(Cu,Mn,Fe)_(3)O_(4)spinel and an internal layer of Cr-rich oxide was thermally developed on the coated steel.The scale area-specific resistances(ASRs)of the coated steels were lower than the scale ASR of the uncoated steel after identical thermal exposure.The external layer of CuO/(Cu,Mn,Fe)_(3)O_(4)spinel not only served as a barrier to reduce the growth rate of Cr-rich oxide internal layer and to suppress the outward diffusion of Cr,but also lowered the surface scale ASRs considerably. 展开更多
关键词 solid oxide fuel cell steel interconnect Cu-Mn_(3)O_(4)composite coating area specific resistance
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阴极电流密度对6061铝合金在含Na_(2)WO_(4)电解液中微弧氧化膜结构和耐磨性能的影响 被引量:2
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作者 邵明增 武宏 +2 位作者 杨洪波 杨蕾 王强 《表面技术》 EI CAS CSCD 北大核心 2024年第1期87-95,共9页
目的 研究恒流模式下阴极电流密度对6061铝合金在含Na2WO4的电解液中制备的微弧氧化膜厚度、形貌、相组成及耐磨性能的影响。方法 固定阳极电流密度为5.0 A/dm^(2),阴极电流密度分别为0、1.25、2.5、3.75、5.0 A/dm2,对6061铝合金进行... 目的 研究恒流模式下阴极电流密度对6061铝合金在含Na2WO4的电解液中制备的微弧氧化膜厚度、形貌、相组成及耐磨性能的影响。方法 固定阳极电流密度为5.0 A/dm^(2),阴极电流密度分别为0、1.25、2.5、3.75、5.0 A/dm2,对6061铝合金进行微弧氧化40 min。用涡流测厚仪测量了氧化膜的厚度,用扫描电镜观察了微弧氧化膜的表面形貌和截面形貌,用能谱分析仪分析了氧化膜的表面成分,用X射线衍射分析仪分析了微弧氧化膜的相组成,用往复式摩擦磨损试验机测试了氧化膜的耐磨性能。结果 随着阴极电流密度的增加,氧化膜内的W含量逐渐减少,氧化膜颜色逐渐变浅,氧化膜厚度逐渐增加。微弧氧化膜的主要组成相为α-Al2O3和γ-Al2O3。当阴极电流密度从0 A/dm2增加到3.75 A/dm2时,氧化膜内孔洞的数量和尺寸逐渐减少,孔洞到氧化膜/基体界面的距离逐渐增加,氧化膜的耐磨性能逐渐提升。当阴极电流密度为3.75 A/dm2时,氧化膜的磨损率最低,仅为1.07×10-4mm3/(N·m)。但阴极电流密度增加到5.0 A/dm2时,氧化膜表层出现孔洞和剥落,耐磨性能下降。结论 阴极电流的加入有助于增加6061铝合金微弧氧化膜的厚度,提高氧化膜的致密性和耐磨性能,但过高的阴极电流会导致氧化膜表层出现孔洞,降低耐磨性能。 展开更多
关键词 铝合金 微弧氧化 阴极电流 钨酸钠 耐磨性能
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火焰喷雾热解合成Pt/TiO_(2)纳米颗粒的催化燃烧性能
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作者 徐祖伟 高富昌 +1 位作者 龙周禾 赵海波 《燃烧科学与技术》 CAS CSCD 北大核心 2024年第2期103-110,共8页
采用火焰喷雾热解方法(FSP)合成了一系列不同Pt负载量的Pt/TiO_(2)催化剂,通过XPS、ICP-OES、ACHAADF-STEM、H_(2)-TPR等表征手段分析了催化剂的成分结构和金属-载体相互作用,在固定床催化反应系统上评估了这些催化剂对CO和CH_(4)的催... 采用火焰喷雾热解方法(FSP)合成了一系列不同Pt负载量的Pt/TiO_(2)催化剂,通过XPS、ICP-OES、ACHAADF-STEM、H_(2)-TPR等表征手段分析了催化剂的成分结构和金属-载体相互作用,在固定床催化反应系统上评估了这些催化剂对CO和CH_(4)的催化燃烧性能.结果表明,FSP合成的Pt/TiO_(2)催化剂具有较大的比表面积、Pt组分富集于TiO_(2)表面,能够显著降低CO和CH_(4)催化燃烧的反应温度,同时也具有较好的高温热稳定性.Pt组分的多种价态对CO和CH_(4)的催化表现出不同的特性,氧化态的单原子Pt对CO具有很好的低温催化活性,而金属态的颗粒Pt对CH_(4)的转化更有利.因此FSP能够在一定范围内调控贵金属催化剂的负载状态和配位环境以适应不同催化反应的需求,提高催化剂设计的灵活性和针对性. 展开更多
关键词 火焰喷雾热解 单原子催化剂 催化燃烧 CO CH_(4)
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C_(2)H_(2)/CH_(4)燃烧特性实验及反应动力学研究
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作者 刘宇 罗蒙蒙 +3 位作者 田富超 谷午 王凯 梁运涛 《燃烧科学与技术》 CAS CSCD 北大核心 2024年第5期473-480,共8页
随着煤矿开采深度的增加,极易出现瓦斯与煤自燃灾害交织共生现象,增大灾害风险.为阐明煤与瓦斯共生灾害发生时的火焰传播特性,有必要开展煤自燃气体掺混对瓦斯燃烧特性的影响研究.乙炔气体(C_(2)H_(2))是煤高温氧化时产生的主要气体之一... 随着煤矿开采深度的增加,极易出现瓦斯与煤自燃灾害交织共生现象,增大灾害风险.为阐明煤与瓦斯共生灾害发生时的火焰传播特性,有必要开展煤自燃气体掺混对瓦斯燃烧特性的影响研究.乙炔气体(C_(2)H_(2))是煤高温氧化时产生的主要气体之一,甲烷(CH_(4))是瓦斯的主要成分,本文研究了0~2%体积分数C_(2)H_(2)掺混对CH_(4)层流燃烧速度的影响规律.结果表明,随着C_(2)H_(2)体积分数的增加,C_(2)H_(2)/CH_(4)混合燃料层流燃烧速度增大.层流燃烧速度受质热扩散作用、动力学和热力学效应的综合影响,当C_(2)H_(2)体积分数增加至2%时,混合燃料的(αLe)^(1/2)、T_(ad)分别增加了1.54%、2.98%,T_(a)减少了26.93%,说明动力学效应是C_(2)H_(2)促进CH_(4)层流燃烧速度增加的主导因素.由活性自由基体积分数分析可知,随着C_(2)H_(2)体积分数的增加,H、O、OH和CH_(3)等活性自由基体积分数均出现增加趋势,从而促进了CH_(4)的燃烧. 展开更多
关键词 C_(2)H_(2)/CH_(4)混合燃料 层流燃烧速度 动力学效应 敏感性分析 活性自由基
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2022年8月北黄海北部溶解甲烷分布、海-气交换通量及影响因素
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作者 徐雪梅 王明丽 +4 位作者 何宗财 韩建波 邢庆会 王心怡 陈虹 《海洋科学进展》 CAS CSCD 北大核心 2024年第4期782-793,共12页
科学评估陆架边缘海溶解甲烷(CH_(4))的分布及海-气交换通量对于认识陆架边缘海CH_(4)的释放对大气CH_(4)的区域性贡献具有重要意义。基于2022年8月的现场调查数据和资料,研究北黄海北部海水溶解CH_(4)的分布、海-气交换通量及影响因素... 科学评估陆架边缘海溶解甲烷(CH_(4))的分布及海-气交换通量对于认识陆架边缘海CH_(4)的释放对大气CH_(4)的区域性贡献具有重要意义。基于2022年8月的现场调查数据和资料,研究北黄海北部海水溶解CH_(4)的分布、海-气交换通量及影响因素。结果表明:研究海域溶解CH_(4)浓度为4.0~63.3 nmol/L,饱和度为168%~2 360%,高值区位于鸭绿江口附近海域,随着离岸距离的增加表层海水溶解CH_(4)浓度迅速降低。鸭绿江等陆源冲淡水的输入耦合海水及沉积物有机质的降解致使近岸海域海水CH_(4)升高;陆源冲淡水与海水混合过程中海水CH_(4)的氧化消耗也是控制CH_(4)浓度和分布不容忽视的重要过程。离岸海域海水及沉积物有机质厌氧降解耦合黄海冷水团的作用使得底层海水溶解CH_(4)浓度高于表层海水。研究海域海-气CH_(4)交换通量为18.4~578.8μmol/(m^(2)·d),是大气CH_(4)的源;鸭绿江口附近海域海-气CH_(4)交换通量高于离岸海域。由此可见,受陆源冲淡水输入的影响研究海域溶解CH_(4)浓度和海-气交换通量具有显著的区域性差异,且变幅高于世界其他海域;加强河口以及近海调查研究对于准确评估陆架边缘海CH_(4)的排放,明确CH_(4)排放源项的构成及制定CH_(4)减排的有效措施至关重要。 展开更多
关键词 北黄海 溶解甲烷 海-气CH_4交换通量 冲淡水输入 有机质厌氧降解
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Improved Corrosion Behavior of Biodegradable Mg-4Zn-1Mn Alloy Modified by Sr/F co-doped CaP Micro-arc Oxidation Coatings
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作者 Weirong LI Yanfang LI +7 位作者 Qian LI Xuan XIONG Fangfei LIU Ronghui LI Heng LI Dong PANG Jia LU Xuan ZHANG 《Research and Application of Materials Science》 2023年第2期1-8,共8页
The Sr/F co-doped CaP(Sr/F-CaP)coatings were prepared by micro-arc oxidation(MAO)under different voltages to modify the microstructure and corrosion behavior of Mg-4Zn-1Mn alloy.The surface and interface characteristi... The Sr/F co-doped CaP(Sr/F-CaP)coatings were prepared by micro-arc oxidation(MAO)under different voltages to modify the microstructure and corrosion behavior of Mg-4Zn-1Mn alloy.The surface and interface characteristics investigated using scanning electron microscopy(SEM)and energy dispersive X-ray spectrometer(EDS)showed that the MAO coatings displayed uneven crater-like holes and tiny cracks under lower voltage,while they exhibited relatively homogeneous crater-like holes without cracks under higher voltage.The thickness of MAO coatings increased with increasing voltage.The corrosion behavior of Mg-4Zn-1Mn alloy was improved by the MAO coatings.The MAO coatings prepared under 450 V and 500 V voltages possessed the best corrosion resistance with regard to the electrochemical corrosion tests and immersion corrosion tests,respectively.The MAO coatings fabricated under 450-500 V could provide a better corrosion protection effect for the substrate. 展开更多
关键词 Biodegradable Mg alloys Mg-4Zn-1Mn alloy Micro-arc oxidation Sr/F co-doped CaP coatings
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Co(x)/ZRP催化剂的CH_(4)-SCR脱硝性能研究
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作者 林世静 王龙帅 +7 位作者 马宇彤 张丽芳 钟绍轩 汪澈 王轩 卢毅 卢学斌 王虹 《北京石油化工学院学报》 2024年第3期1-7,共7页
为消除氮氧化物对人类健康和生态环境的危害,以甲烷为还原剂进行选择性催化脱硝(CH_(4)-SCR)得到了普遍的关注。研发高活性的CH_(4)-SCR脱硝催化剂成为该技术的研究重点。采用浸渍法制备了Co(x)/ZRP催化剂,考察了钴负载量对Co(x)/ZRP催... 为消除氮氧化物对人类健康和生态环境的危害,以甲烷为还原剂进行选择性催化脱硝(CH_(4)-SCR)得到了普遍的关注。研发高活性的CH_(4)-SCR脱硝催化剂成为该技术的研究重点。采用浸渍法制备了Co(x)/ZRP催化剂,考察了钴负载量对Co(x)/ZRP催化剂CH_(4)-SCR脱硝性能的影响。利用X射线衍射仪(XRD)、H_(2)程序升温还原(H_(2)-TPR)、吡啶吸附红外光谱(Py-IR)、NH_(3)程序升温脱附(NH_(3)-TPD)和NO程序升温脱附(NO-TPD)等对Co(x)/ZRP催化剂的理化性质进行了表征,在常压固定床微型反应器上评价了Co(x)/ZRP催化剂的CH_(4)-SCR脱硝性能。结果表明:Co(x)/ZRP催化剂中钴物种为Co_(3)O_(4),钴负载量增加,Co_(3)O_(4)晶粒变大,催化剂的氧化还原能力和NO的吸脱附性能均得到改善。随着钴负载量的增加,Co(x)/ZRP催化剂的CH_(4)-SCR脱硝活性先增强后降低,与催化剂中的中强酸量在总酸中的变化规律基本一致。其中Co(20)/ZRP催化剂的中强酸量较多,CH_(4)-SCR脱硝性能较好,T_(m)为342℃,X_(No)^(max)为39.2%。催化剂表面的L酸位以及中强酸量对催化剂的CH_(4)-SCR催化脱硝活性具有重要作用。 展开更多
关键词 Co_(3)O_(4) NO ZRP分子筛 甲烷 选择性催化还原
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