针对吸附强化乙醇水蒸气重整(SE-SRE)制氢技术,通过热力学分析和制氢实验,研究了硅酸锂加入乙醇重整的效果,并结合多种表征手段分析了掺杂K对硅酸锂的影响,进一步用实验方法探究了多种工艺条件对以掺钾硅酸锂为吸附剂的SE-SRE系统的影...针对吸附强化乙醇水蒸气重整(SE-SRE)制氢技术,通过热力学分析和制氢实验,研究了硅酸锂加入乙醇重整的效果,并结合多种表征手段分析了掺杂K对硅酸锂的影响,进一步用实验方法探究了多种工艺条件对以掺钾硅酸锂为吸附剂的SE-SRE系统的影响及该系统的循环稳定性.结果表明,硅酸锂加入乙醇重整提高了氢气产率,适量掺钾能改善硅酸锂的结晶度和孔隙特性,提升其吸附性能.SE-SRE系统的最佳工艺条件是:温度为525℃,空速为0.9 m L/(g·h),水醇体积比为8∶1,催化剂与吸附剂配比为1∶3,经过10次循环后SE-SRE系统仍能保持较高的二氧化碳吸附活性和氢气产率.展开更多
The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(...The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In_(2.77)S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2) production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In_(2.77)S_(4)/respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In_(2.77)S_(4) according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2) production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2) around the active centers,the energy barriers of O_(2) protonation and H_(2)O_(2) desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2) photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.展开更多
Carbon with its high electrical conductivity,excellent chemical stability,and structure ability is the most promising an-ode material for sodium and potassium ion batteries.We developed a defect-rich porous carbon fra...Carbon with its high electrical conductivity,excellent chemical stability,and structure ability is the most promising an-ode material for sodium and potassium ion batteries.We developed a defect-rich porous carbon framework(DRPCF)built with N/O-co-doped mesoporous nanosheets and containing many defects using porous g-C_(3)N_(4)(PCN)and dopamine(DA)as raw materials.We prepared samples with PCN/DA mass ratios of 1/1,2/1 and 3/1 and found that the one with a mass ratio of 2/1 and a carbonization temperature of 700℃ in an Ar atmosphere(DRPCF-2/1-700),had a large specific surface area with an enormous pore volume and a large number of N/O heteroatom active defect sites.Because of this,it had the best pseudocapacitive sodium and potassium ion stor-age performance.A half battery of Na//DRPCF-2/1-700 maintained a capacity of 328.2 mAh g^(-1) after being cycled at 1 A g^(-1) for 900 cycles,and a half battery of K//DRPC-2/1-700 maintained a capacity of 321.5 mAh g^(-1) after being cycled at 1 A g^(-1) for 1200 cycles.The rate capability and cycling stability achieved by DRPCF-2/1-700 outperforms most reported carbon materials.Finally,ex-situ Raman spectroscopy analysis result confirms that the filling and removing of K^(+)and Na^(+)from the electrochemically active defects are responsible for the high capacity,superior rate and cycling performance of the DRPCF-2/1-700 sample.展开更多
A series of K-doped Mn0.5Ce0.5Oδ （K-MCO） catalysts with three-dimensionally ordered macroporous （3DOM） structure and different K loadings were successfully synthesized using simple methods. These catalysts exhibi...A series of K-doped Mn0.5Ce0.5Oδ （K-MCO） catalysts with three-dimensionally ordered macroporous （3DOM） structure and different K loadings were successfully synthesized using simple methods. These catalysts exhibited well-defined 3DOM nanostructure, which consisted of extensive interconnecting networks of spherical voids. The effects of the calcination temperature and calcination time on the morphological characteristics and crystalline forms of the catalysts were systematically studied. The catalysts showed high catalytic activity for the combustion of soot. 3DOM 20% K-MCO-4h catalyst, in particular, showed the highest catalytic activity of all of the catalysts studied （e.g., Ts0 = 331 ~C and Smco2 = 95.3%）. The occurrence of structural and synergistic effects among the K, Mn, and Ce atoms in the catalysts was favorable for enhancing their catalytic activity towards the combustion of diesel soot. Furthermore, the temperatures required for the complete combustion of the soot （〈400 ℃） were well within the exhaust temperature range （175-400 ℃）, which means that the accumulated soot can be removed under the conditions of the diesel exhaust gas. These catalysts could therefore be used in numerous practical applications because they are easy to synthesize, exhibit high catalytic activity, and can be made from low cost materials.展开更多
文摘针对吸附强化乙醇水蒸气重整(SE-SRE)制氢技术,通过热力学分析和制氢实验,研究了硅酸锂加入乙醇重整的效果,并结合多种表征手段分析了掺杂K对硅酸锂的影响,进一步用实验方法探究了多种工艺条件对以掺钾硅酸锂为吸附剂的SE-SRE系统的影响及该系统的循环稳定性.结果表明,硅酸锂加入乙醇重整提高了氢气产率,适量掺钾能改善硅酸锂的结晶度和孔隙特性,提升其吸附性能.SE-SRE系统的最佳工艺条件是:温度为525℃,空速为0.9 m L/(g·h),水醇体积比为8∶1,催化剂与吸附剂配比为1∶3,经过10次循环后SE-SRE系统仍能保持较高的二氧化碳吸附活性和氢气产率.
文摘The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In_(2.77)S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2) production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In_(2.77)S_(4)/respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In_(2.77)S_(4) according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2) production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2) around the active centers,the energy barriers of O_(2) protonation and H_(2)O_(2) desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2) photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.
文摘Carbon with its high electrical conductivity,excellent chemical stability,and structure ability is the most promising an-ode material for sodium and potassium ion batteries.We developed a defect-rich porous carbon framework(DRPCF)built with N/O-co-doped mesoporous nanosheets and containing many defects using porous g-C_(3)N_(4)(PCN)and dopamine(DA)as raw materials.We prepared samples with PCN/DA mass ratios of 1/1,2/1 and 3/1 and found that the one with a mass ratio of 2/1 and a carbonization temperature of 700℃ in an Ar atmosphere(DRPCF-2/1-700),had a large specific surface area with an enormous pore volume and a large number of N/O heteroatom active defect sites.Because of this,it had the best pseudocapacitive sodium and potassium ion stor-age performance.A half battery of Na//DRPCF-2/1-700 maintained a capacity of 328.2 mAh g^(-1) after being cycled at 1 A g^(-1) for 900 cycles,and a half battery of K//DRPC-2/1-700 maintained a capacity of 321.5 mAh g^(-1) after being cycled at 1 A g^(-1) for 1200 cycles.The rate capability and cycling stability achieved by DRPCF-2/1-700 outperforms most reported carbon materials.Finally,ex-situ Raman spectroscopy analysis result confirms that the filling and removing of K^(+)and Na^(+)from the electrochemically active defects are responsible for the high capacity,superior rate and cycling performance of the DRPCF-2/1-700 sample.
基金supported by the National Natural Science Foundation of China(21177160,21303263,21477164)Beijing Nova Program(Z141109001814072)+1 种基金Specialized Research Fund for the Doctoral Program of High Education of China(20130007120011)the Science Foundation of China University of Petroleum-Beijing(2462013YJRC13,2462013BJRC003)~~
文摘A series of K-doped Mn0.5Ce0.5Oδ （K-MCO） catalysts with three-dimensionally ordered macroporous （3DOM） structure and different K loadings were successfully synthesized using simple methods. These catalysts exhibited well-defined 3DOM nanostructure, which consisted of extensive interconnecting networks of spherical voids. The effects of the calcination temperature and calcination time on the morphological characteristics and crystalline forms of the catalysts were systematically studied. The catalysts showed high catalytic activity for the combustion of soot. 3DOM 20% K-MCO-4h catalyst, in particular, showed the highest catalytic activity of all of the catalysts studied （e.g., Ts0 = 331 ~C and Smco2 = 95.3%）. The occurrence of structural and synergistic effects among the K, Mn, and Ce atoms in the catalysts was favorable for enhancing their catalytic activity towards the combustion of diesel soot. Furthermore, the temperatures required for the complete combustion of the soot （〈400 ℃） were well within the exhaust temperature range （175-400 ℃）, which means that the accumulated soot can be removed under the conditions of the diesel exhaust gas. These catalysts could therefore be used in numerous practical applications because they are easy to synthesize, exhibit high catalytic activity, and can be made from low cost materials.
