Ni/Mg–Al catalysts derived from hydrotalcite-type precursors were prepared by a co-precipitation technique and applied to steam reforming of methane. By comparison with Ni/γ-Al2O3 and Ni/α-Al2O3 catalysts prepared ...Ni/Mg–Al catalysts derived from hydrotalcite-type precursors were prepared by a co-precipitation technique and applied to steam reforming of methane. By comparison with Ni/γ-Al2O3 and Ni/α-Al2O3 catalysts prepared by incipient wetness impregnation, the Ni/Mg–Al catalyst presented much higher activity as a result of higher specific surface area and better Ni dispersion. The Ni/Mg–Al catalyst with a Ni/Mg/Al molar ratio of 0.5:2.5:1 exhibited the highest activity for steam methane reforming and was selected for kinetic investigation. With external and internal diffusion limitations eliminated, kinetic experiments were carried out at atmospheric pressure and over a temperature range of 823–973 K. The results demonstrated that the overall conversion of CH4 and the conversion of CH4 to CO2were strongly influenced by reaction temperature, residence time of reactants as well as molar ratio of steam to methane. A classical Langmuir–Hinshelwood kinetic model proposed by Xu and Froment(1989)fitted the experimental data with excellent agreement. The estimated adsorption parameters were consistent thermodynamically.展开更多
The fast-growing procedure （FGP） provides a simple, high-yield and lead （Pb）-release free method to prepare perovskite films. In the FGP, the ultra-dilute per- ovskite precursor solution is drop-cast onto a hot （...The fast-growing procedure （FGP） provides a simple, high-yield and lead （Pb）-release free method to prepare perovskite films. In the FGP, the ultra-dilute per- ovskite precursor solution is drop-cast onto a hot （-240℃） substrate where a perovskite film grows immediately ac- companied by the rapid evaporation of the host solvent. In this process, all the raw materials in the precursor solution are deposited into the final perovskite film. The potential pollution caused by Pb can be significantly reduced. Proper- ties of the FGP-processed perovskite films can be modulated by the precursor composition. While CH3NH3CI （MACI） affects the crystallization process and leads to full surface coverage, CH（NHz）2I （FAI） enhances the thermal stability of the film. Based on the optimized precursor composition of PbI2.（1-x）FAI.xMACI, x=0.75, FGP-processed planar het- erojunction perovskite solar cells exhibit power conversion efficiencies （PCEs） exceeding 15% with suppressed hysteresis and excellent reproducibility.展开更多
Cyclopentazolate anions(cyclo-N5-)have been receiving ever-increasing attention as component of energetic explosives since recent fulfilment of the first stable sample in solid phase and ambient conditions.Herein,we p...Cyclopentazolate anions(cyclo-N5-)have been receiving ever-increasing attention as component of energetic explosives since recent fulfilment of the first stable sample in solid phase and ambient conditions.Herein,we present a new strategy to utilize deflagration reactions of cobalt pentazolate in combination with explosive poly(ionic liquid)(EPIL)for the preparation of Co@N-doped carbon materials with homogeneously distributed cobalt nanoparticle encapsulated by the layers of N-doped carbon sheets.The resultant5%Co(N5)2-EPIL-900 exhibits high electrocatalytic activities,excellent stability and tolerance to CH3 OH towards oxygen reduction reaction(ORR).Moreover,the present approach provides a novel routine for preparation of functional materials from energetic and newly-emerging cyclo-N5--derived compounds.展开更多
A new type of ultraviolet photo-detectors （UVPDs） based on a bundle of highly aligned SiC nanowires was fabricated and the photo-electric properties of the UVPDs including 1-V characteristics and time response were ...A new type of ultraviolet photo-detectors （UVPDs） based on a bundle of highly aligned SiC nanowires was fabricated and the photo-electric properties of the UVPDs including 1-V characteristics and time response were studied in this work. SiC nan- owires were prepared by pyrolysis of a polymer precursor with ferrocene as the catalyst by a CVD route. The diameters of SiC nanowires varied from 100 to 200 nm while they were some centimeters long and the SiC nanowires were with zinc blended cubic form （β-SiC） tested by X-ray diffraction. A bundle of nanowires was fixed onto two legs＇ base by conductive silver paste to form the UVPDs. The electrical measurement of the device showed a significant increase of current when the device was exposed to 254 nm UV light, and the rising time of the device is very short, but the falling time is relatively long. Our results show that the UVPDs based on SiC nanowires have excellent electrical and optical properties which can be potentially applied.展开更多
基金Supported by the National Natural Science Foundation of China(21276076)the Program for New Century Excellent Talents in University(NCET-13-0801)the Fundamental Research Funds for the Central Universities(222201313011)
文摘Ni/Mg–Al catalysts derived from hydrotalcite-type precursors were prepared by a co-precipitation technique and applied to steam reforming of methane. By comparison with Ni/γ-Al2O3 and Ni/α-Al2O3 catalysts prepared by incipient wetness impregnation, the Ni/Mg–Al catalyst presented much higher activity as a result of higher specific surface area and better Ni dispersion. The Ni/Mg–Al catalyst with a Ni/Mg/Al molar ratio of 0.5:2.5:1 exhibited the highest activity for steam methane reforming and was selected for kinetic investigation. With external and internal diffusion limitations eliminated, kinetic experiments were carried out at atmospheric pressure and over a temperature range of 823–973 K. The results demonstrated that the overall conversion of CH4 and the conversion of CH4 to CO2were strongly influenced by reaction temperature, residence time of reactants as well as molar ratio of steam to methane. A classical Langmuir–Hinshelwood kinetic model proposed by Xu and Froment(1989)fitted the experimental data with excellent agreement. The estimated adsorption parameters were consistent thermodynamically.
基金financially supported by the National Basic Research Program of China (973 Program) (2015CB932203)the National Natural Science Foundation of China (61377025, 91433203, and 11121091)+2 种基金the Young 1000 Talents Global Recruitment Program of Chinasupported by the US Office of Naval Research under contract N00014-15-1-2244the support from the US National Science Foundation (DMR-1305913 and OIA-1538893)
文摘The fast-growing procedure （FGP） provides a simple, high-yield and lead （Pb）-release free method to prepare perovskite films. In the FGP, the ultra-dilute per- ovskite precursor solution is drop-cast onto a hot （-240℃） substrate where a perovskite film grows immediately ac- companied by the rapid evaporation of the host solvent. In this process, all the raw materials in the precursor solution are deposited into the final perovskite film. The potential pollution caused by Pb can be significantly reduced. Proper- ties of the FGP-processed perovskite films can be modulated by the precursor composition. While CH3NH3CI （MACI） affects the crystallization process and leads to full surface coverage, CH（NHz）2I （FAI） enhances the thermal stability of the film. Based on the optimized precursor composition of PbI2.（1-x）FAI.xMACI, x=0.75, FGP-processed planar het- erojunction perovskite solar cells exhibit power conversion efficiencies （PCEs） exceeding 15% with suppressed hysteresis and excellent reproducibility.
基金financially supported by the National Natural Science Foundation of China(21703218 and21875228)Shenzhen Science and Technology Innovation Committee(JCYJ20151013162733704)
文摘Cyclopentazolate anions(cyclo-N5-)have been receiving ever-increasing attention as component of energetic explosives since recent fulfilment of the first stable sample in solid phase and ambient conditions.Herein,we present a new strategy to utilize deflagration reactions of cobalt pentazolate in combination with explosive poly(ionic liquid)(EPIL)for the preparation of Co@N-doped carbon materials with homogeneously distributed cobalt nanoparticle encapsulated by the layers of N-doped carbon sheets.The resultant5%Co(N5)2-EPIL-900 exhibits high electrocatalytic activities,excellent stability and tolerance to CH3 OH towards oxygen reduction reaction(ORR).Moreover,the present approach provides a novel routine for preparation of functional materials from energetic and newly-emerging cyclo-N5--derived compounds.
基金the National Natural Science Foundation of China (Grant No. 11104348)the School Pre-research of National University of Defense Technology (Grant No. JC11-02-08) for the financial support to this work
文摘A new type of ultraviolet photo-detectors （UVPDs） based on a bundle of highly aligned SiC nanowires was fabricated and the photo-electric properties of the UVPDs including 1-V characteristics and time response were studied in this work. SiC nan- owires were prepared by pyrolysis of a polymer precursor with ferrocene as the catalyst by a CVD route. The diameters of SiC nanowires varied from 100 to 200 nm while they were some centimeters long and the SiC nanowires were with zinc blended cubic form （β-SiC） tested by X-ray diffraction. A bundle of nanowires was fixed onto two legs＇ base by conductive silver paste to form the UVPDs. The electrical measurement of the device showed a significant increase of current when the device was exposed to 254 nm UV light, and the rising time of the device is very short, but the falling time is relatively long. Our results show that the UVPDs based on SiC nanowires have excellent electrical and optical properties which can be potentially applied.
