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101.
Saurav Ch Sarma Jesús Barrio Alexander Bagger Angus Pedersen Mengjun Gong Hui Luo Mengnan Wang Silvia Favero Chang-Xin Zhao Qiang Zhang Anthony Kucernak Maria-Magdalena Titirici Ifan E. L. Stephens 《Advanced functional materials》2023,33(41):2302468
The electrochemical CO2 reduction reaction (CO2RR) to value-added chemicals with renewable electricity is a promising method to decarbonize parts of the chemical industry. Recently, single metal atoms in nitrogen-doped carbon (MNC) have emerged as potential electrocatalysts for CO2RR to CO with high activity and faradaic efficiency, although the reaction limitation for CO2RR to CO is unclear. To understand the comparison of intrinsic activity of different MNCs, two catalysts are synthesized through a decoupled two-step synthesis approach of high temperature pyrolysis and low temperature metalation (Fe or Ni). The highly meso-porous structure results in the highest reported electrochemical active site utilization based on in situ nitrite stripping; up to 59±6% for NiNC. Ex situ X-ray absorption spectroscopy (XAS) confirms the penta-coordinated nature of the active sites. The catalysts are amongst the most active in the literature for CO2 reduction to CO. The density functional theory calculations (DFT) show that their binding to the reaction intermediates approximates to that of Au surfaces. However, it is found that the turnover frequencies (TOFs) of the most active catalysts for CO evolution converge, suggesting a fundamental ceiling to the catalytic rates. 相似文献
102.
Youyu Duan Yang Wang Weixuan Zhang Jiangwei Zhang Chaogang Ban Danmei Yu Kai Zhou Jinjing Tang Xu Zhang Xiaodong Han Liyong Gan Xiaoping Tao Xiaoyuan Zhou 《Advanced functional materials》2023,33(28):2301729
Photocatalytic conversion of CO2 into fuels using pure water as the proton source is of immense potential in simultaneously addressing the climate-change crisis and realizing a carbon-neutral economy. Single-atom photocatalysts with tunable local atomic configurations and unique electronic properties have exhibited outstanding catalytic performance in the past decade. However, given their single-site features they are usually only amenable to activations involving single molecules. For CO2 photoreduction entailing complex activation and dissociation process, designing multiple active sites on a photocatalyst for both CO2 reduction and H2O dissociation simultaneously is still a daunting challenge. Herein, it is precisely construct Cu single-atom centers and two-coordinated N vacancies as dual active sites on CN (Cu1/N2CV-CN). Experimental and theoretical results show that Cu single-atom centers promote CO2 chemisorption and activation via accumulating photogenerated electrons, and the N2CV sites enhance the dissociation of H2O, thereby facilitating the conversion from COO* to COOH*. Benefiting from the dual-functional sites, the Cu1/N2CV-CN exhibits a high selectivity (98.50%) and decent CO production rate of 11.12 µmol g−1 h−1. An ingenious atomic-level design provides a platform for precisely integrating the modified catalyst with the deterministic identification of the electronic property during CO2 photoreduction process. 相似文献
103.
针对跨临界CO_2压缩制冷系统制取冷量以消耗高品位能量为代价的问题,本文依据能量梯级利用原理,提出双温低品位热源驱动的新型CO_2-[emim][Tf_2N]吸收式制冷循环的新流程,在构建该制冷循环数学模型的基础上,搭建测试双温驱动吸收制冷循环性能的实验装置,利用模拟和实验方法分析了操作参数对系统性能的影响规律。在定流量的条件下,研究驱动热源温度、冷却水入口温度以及载冷剂入口温度等操作参数对新系统性能的影响规律,结果表明双温驱动新型吸收制冷系统不仅可实现高效制冷,而且最低制冷温度可达到-15.2℃,研究结果为CO_2-离子液体制冷系统的理论设计计算提供实用的数据基础。 相似文献
104.
Huijun Yu Run Shi Yufei Zhao Geoffrey I. N. Waterhouse Li‐Zhu Wu Chen‐Ho Tung Tierui Zhang 《Advanced materials (Deerfield Beach, Fla.)》2016,28(43):9454-9477
Efficient capture of solar energy will be critical to meeting the energy needs of the future. Semiconductor photocatalysis is expected to make an important contribution in this regard, delivering both energy carriers (especially H2) and valuable chemical feedstocks under direct sunlight. Over the past few years, carbon dots (CDs) have emerged as a promising new class of metal‐free photocatalyst, displaying semiconductor‐like photoelectric properties and showing excellent performance in a wide variety of photoelectrochemical and photocatalytic applications owing to their ease of synthesis, unique structure, adjustable composition, ease of surface functionalization, outstanding electron‐transfer efficiency and tunable light‐harvesting range (from deep UV to the near‐infrared). Here, recent advances in the rational design of CDs‐based photocatalysts are highlighted and their applications in photocatalytic environmental remediation, water splitting into hydrogen, CO2 reduction, and organic synthesis are discussed. 相似文献
105.
本文研究了Si/C锂离子电池负极材料中K_2CO_3的添加对提高电极电化学性能的作用及其作用机理。采用恒流充放电测试和电化学阻抗谱(EIS)研究了不同K_2CO_3添加量对Si/C负极电化学性能的影响;通过扫描电镜(SEM)和傅里叶红外光谱(FTIR)等方法分析了K_2CO_3添加对Si/C负极在循环过程中结构和成分变化的影响。研究结果表明,加入K_2CO_3后,由于电极在循环过程中结构稳定性增强以及电极的固体电解质界面(SEI)膜阻抗和电荷转移阻抗减少,使Si/C负极的循环稳定性和倍率性能得到明显提高。 相似文献
106.
Fabricating Ir/C Nanofiber Networks as Free‐Standing Air Cathodes for Rechargeable Li‐CO2 Batteries 下载免费PDF全文
Chengyi Wang Qinming Zhang Xin Zhang Xin‐Gai Wang Zhaojun Xie Zhen Zhou 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(28)
Li‐CO2 batteries are promising energy storage systems by utilizing CO2 at the same time, though there are still some critical barriers before its practical applications such as high charging overpotential and poor cycling stability. In this work, iridium/carbon nanofibers (Ir/CNFs) are prepared via electrospinning and subsequent heat treatment, and are used as cathode catalysts for rechargeable Li‐CO2 batteries. Benefitting from the unique porous network structure and the high activity of ultrasmall Ir nanoparticles, Ir/CNFs exhibit excellent CO2 reduction and evolution activities. The Li‐CO2 batteries present extremely large discharge capacity, high coulombic efficiency, and long cycling life. Moreover, free‐standing Ir/CNF films are used directly as air cathodes to assemble Li‐CO2 batteries, which show high energy density and ultralong operation time, demonstrating great potential for practical applications. 相似文献
107.
108.
Feng-Renn JuangAuthor VitaeYean-Kuen FangAuthor Vitae Yen-Ting ChiangAuthor VitaeTse-Heng ChouAuthor Vitae Cheng-I. LinAuthor VitaeCheng-Wei LinAuthor Vitae 《Sensors and actuators. B, Chemical》2011,156(1):338-342
The Au/SnO2/n-LTPS MOS Schottky diode prepared on a glass substrate for carbon monoxide (CO) sensing applications is studied. The n-LTPS (n-type low temperature polysilicon) is prepared by excimer laser annealing and PH3 plasma treatment of an amorphous Si thin film on glass substrate. The developed Schottky diode exhibits a high relative response ratio of ∼546% to 100 ppm CO ambient under condition of 200 °C and −3 V bias. The response ratio is better than the reported SnO2 based resistive type CO sensors of 100% and 37%, respectively on poly-alumina and glass substrates or comparable to 390% of Pt-AlGaN/GaN Schottky diode CO sensor. Thus, the Au/SnO2/n-LTPS Schottky diode has the potential to develop a low cost high performance CO sensor. 相似文献
109.
Hiroyuki YamauraAuthor VitaeYuji IwasakiAuthor Vitae Shinsuke HiraoAuthor VitaeHidenori YahiroAuthor Vitae 《Sensors and actuators. B, Chemical》2011,153(2):465-467
The CO sensing property of CuO-loaded SnO2-In2O3 sensor was investigated in a reducing atmosphere. The sensor response to CO for CuO/SnO2-In2O3 (8/2) was much higher than that for CuO/SnO2 in the range of 200-1000 ppm of CO concentration. Such a high sensor response of CuO/SnO2-In2O3 may originate from the high dispersion of CuO playing a role as sensing site. 相似文献
110.
Yeon-Tae YuAuthor Vitae Prabir DuttaAuthor Vitae 《Sensors and actuators. B, Chemical》2011,157(2):444-449
Au/SnO2 core-shell structure nanoparticles (NPs) were synthesized using two methods, microwave and conventional precipitation. In both cases, the size of the Au core was 12-18 nm and the thickness of the SnO2 shell was 8-12 nm. The particle size of SnO2 synthesized using the microwave and precipitation method was 3-5 nm and 1-2 nm, respectively. Upon heating to 400-600 °C, both particles maintained their core-shell morphology but the smaller SnO2 particles prepared using the precipitation method were more sintered. The resistance changes in films of these particles were measured as a function of CO concentration. The Au/SnO2 particles prepared using the microwave method showed higher sensor response than those prepared using the precipitation method, even providing a significant signal at testing temperatures approaching ambient conditions, thereby affording a new class of material for gas sensing. Both sets of core-shell particles showed higher sensor response than the SnO2 nanoparticles. The role of the Au core as a catalyst in improving the adsorption and oxidation of CO gas is important for improving the low temperature response. In addition, the maintenance of the size of SnO2 in the microwave method during sintering contributed to the higher response towards CO sensing. 相似文献