A new strategy to fabricate oxygen-promoted Cu,N co-doped carbon(OP-CuN@C)composites is reported.The strategy consists of only two simple steps:chemical polymerization and high temperature carbonization.Electrochemica...A new strategy to fabricate oxygen-promoted Cu,N co-doped carbon(OP-CuN@C)composites is reported.The strategy consists of only two simple steps:chemical polymerization and high temperature carbonization.Electrochemical measurements were conducted to investigate the catalytic activity and mechanism of ORR on the resulting samples.All the electrochemical results indicate that OP-CuN@C exhibits the best ORR catalytic activity.The ORR onset potential of OP-CuN@C is slightly lower than that of commercial Pt/C catalyst.The good performance is attributed to the large specific surface area,high content of heteroatoms(pyridinic,graphitic nitrogen,and oxygen atom)and synergistic effect between divalent copper and nitrogen dopant.展开更多
Elevated-temperature pressure swing adsorption is a promising technique for producing high purity hydrogen and controlling greenhouse gas emissions. Thermodynamic analysis indicated that the CO in H-rich gas could be ...Elevated-temperature pressure swing adsorption is a promising technique for producing high purity hydrogen and controlling greenhouse gas emissions. Thermodynamic analysis indicated that the CO in H-rich gas could be controlled to trace levels of below 10 ppm by in situ reduction of the COconcentration to less than 100 ppm via the aforementioned process. The COadsorption capacity of potassiumpromoted hydrotalcite at elevated temperatures under different adsorption（mole fraction, working pressure） and desorption（flow rate, desorption time, steam effects） conditions was systematically investigated using a fixed bed reactor. It was found that the COresidual concentration before the breakthrough of COmainly depended on the total amount of purge gas and the COmole fraction in the inlet syngas.The residual COconcentration and uptake achieved for the inlet gas comprising CO（9.7 mL/min） and He（277.6 mL/min） at a working pressure of 3 MPa after 1 h of Ar purging at 300 mL/min were 12.3 ppm and0.341 mmol/g, respectively. Steam purge could greatly improve the cyclic adsorption working capacity, but had no obvious benefit for the recovery of the residual COconcentration compared to purging with an inert gas. The residual COconcentration obtained with the adsorbent could be reduced to 3.2 ppm after 12 h of temperature swing at 450 °C. A new concept based on an adsorption/desorption process, comprising adsorption, steam rinse, depressurization, steam purge, pressurization, and high-temperature steam purge, was proposed for reducing the steam consumption during CO/COpurification.展开更多
The development of carbon dioxide(CO_2) sorbents that can operate at elevated temperatures is significant for the advancement of pre-combustion capture technologies.Recently, promoter-based systems composed of alkali/...The development of carbon dioxide(CO_2) sorbents that can operate at elevated temperatures is significant for the advancement of pre-combustion capture technologies.Recently, promoter-based systems composed of alkali/alkaline earth metal nitrates and/or carbonates have been considered as next-generation solid sorbents due to their improved CO_2 uptake and kinetics. However, obtaining stable MgO sorbents against temperature swing regeneration still remained challenging. Herein, we report MgO-TiO_2 solid sorbents promoted by eutectic mixture(KNO_3 and LiNO_3) for elevated temperature CO_2 sorption. The developed sorbents show improved CO_2 sorption capacity, which may be attributed to the alternative CO_2 sorption pathway provided by the ionization of highly dispersed MgO in the eutectic mixture. The MgO-TiO_2 framework was also shown to assist in retaining the MgO configuration by constraining its interaction with CO_2. Furthermore, it is demonstrated that constructing composite structures is essential to improve the CO_2 sorption characteristics,mainly recyclability, at elevated temperatures. The developed promoter integrated sorbents showed exceptionally high CO_2 sorption capacity of > 30 wt.% at an elevated temperature(300°C) with pronounced stability under temperature swing operation.展开更多
基金Funded in Part by the National Key Research and Development Program of China(2017YFB0102801)。
文摘A new strategy to fabricate oxygen-promoted Cu,N co-doped carbon(OP-CuN@C)composites is reported.The strategy consists of only two simple steps:chemical polymerization and high temperature carbonization.Electrochemical measurements were conducted to investigate the catalytic activity and mechanism of ORR on the resulting samples.All the electrochemical results indicate that OP-CuN@C exhibits the best ORR catalytic activity.The ORR onset potential of OP-CuN@C is slightly lower than that of commercial Pt/C catalyst.The good performance is attributed to the large specific surface area,high content of heteroatoms(pyridinic,graphitic nitrogen,and oxygen atom)and synergistic effect between divalent copper and nitrogen dopant.
基金financed by Shanxi Province Science and Technology Major Projects of MH2015-06
文摘Elevated-temperature pressure swing adsorption is a promising technique for producing high purity hydrogen and controlling greenhouse gas emissions. Thermodynamic analysis indicated that the CO in H-rich gas could be controlled to trace levels of below 10 ppm by in situ reduction of the COconcentration to less than 100 ppm via the aforementioned process. The COadsorption capacity of potassiumpromoted hydrotalcite at elevated temperatures under different adsorption（mole fraction, working pressure） and desorption（flow rate, desorption time, steam effects） conditions was systematically investigated using a fixed bed reactor. It was found that the COresidual concentration before the breakthrough of COmainly depended on the total amount of purge gas and the COmole fraction in the inlet syngas.The residual COconcentration and uptake achieved for the inlet gas comprising CO（9.7 mL/min） and He（277.6 mL/min） at a working pressure of 3 MPa after 1 h of Ar purging at 300 mL/min were 12.3 ppm and0.341 mmol/g, respectively. Steam purge could greatly improve the cyclic adsorption working capacity, but had no obvious benefit for the recovery of the residual COconcentration compared to purging with an inert gas. The residual COconcentration obtained with the adsorbent could be reduced to 3.2 ppm after 12 h of temperature swing at 450 °C. A new concept based on an adsorption/desorption process, comprising adsorption, steam rinse, depressurization, steam purge, pressurization, and high-temperature steam purge, was proposed for reducing the steam consumption during CO/COpurification.
基金supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Education (No.NRF 2017R1D1A1B03036324)supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP)the Ministry of Trade,Industry & Energy (MOTIE) of the Republic of Korea (No.20174010201160)
文摘The development of carbon dioxide(CO_2) sorbents that can operate at elevated temperatures is significant for the advancement of pre-combustion capture technologies.Recently, promoter-based systems composed of alkali/alkaline earth metal nitrates and/or carbonates have been considered as next-generation solid sorbents due to their improved CO_2 uptake and kinetics. However, obtaining stable MgO sorbents against temperature swing regeneration still remained challenging. Herein, we report MgO-TiO_2 solid sorbents promoted by eutectic mixture(KNO_3 and LiNO_3) for elevated temperature CO_2 sorption. The developed sorbents show improved CO_2 sorption capacity, which may be attributed to the alternative CO_2 sorption pathway provided by the ionization of highly dispersed MgO in the eutectic mixture. The MgO-TiO_2 framework was also shown to assist in retaining the MgO configuration by constraining its interaction with CO_2. Furthermore, it is demonstrated that constructing composite structures is essential to improve the CO_2 sorption characteristics,mainly recyclability, at elevated temperatures. The developed promoter integrated sorbents showed exceptionally high CO_2 sorption capacity of > 30 wt.% at an elevated temperature(300°C) with pronounced stability under temperature swing operation.
文摘MeLTI6A(Manihot esculenta low temperature inducible 6A)是木薯低温干旱诱导基因,本研究从MeLTI6A的序列出发,利用电子克隆设计引物进行PCR扩增的方法获得该基因的启动子,其序列共1 304 bp。生物信息学分析发现该启动子中具有真核生物典型的核心启动子区(TATA-box和CAAT-box),并利用α-互补,蓝白斑筛选原理验证了该启动子核心序列具有活性;该启动子具有与干旱胁迫相关的激素类(如脱落酸、乙烯)的响应元件和逆境胁迫(如低温、干旱胁迫)的响应元件;还具有与木薯组织特异表达相关的调控元件和其它光响应元件;并通过Real time PCR检测了低温胁迫(4℃)下的木薯组培苗中MeLTI6A的表达变化,说明了该启动子区的低温胁迫顺式作用响应元件可能调节MeLIT6A在低温胁迫下的表达。这些说明木薯的MeLIT6A基因可能是通过对干旱胁迫激素信号响应以及逆境胁迫响应起作用,使木薯获得一定的抗胁迫的能力,同时还可能参与了木薯相关组织发育过程的调控。本研究有利于对MeLTI6A基因抗逆境胁迫功能的理解,为探索木薯高效抗逆的分子机制作初步研究。
