查找使用阿拉丁产品的科研文献

Temperature modulation of defects in NH2-UiO-66(Zr) for photocatalytic CO2 reduction

Yanghe Fu,Jieyu Wu,Rongfei Du,Ke Guo,Rui Ma,Fumin Zhang,Weidong Zhu,Maohong Fan

Defect engineering can be a promising approach to improve the photocatalytic performance of metal–organic frameworks (MOFs). Herein, a series of defective NH2-UiO-66(Zr) materials were synthesized via simply controlling the synthesis temperature, with concentrated HCl as the modulator and then these as-prepared samples were used to systematically investigate the effects of their structural defects on photocatalytic CO2 reduction. Remarkably, these MOFs with defects exhibit significantly enhanced activities in photocatalytic CO2 reduction, compared with the material without defects. The defect engineering creates active binding sites and more open frameworks in the MOF, and thus facilitates the photo-induced charge transfer and restrains the recombination of photo-generated charges efficiently. The current work provides an instructive approach to improve the photocatalytic efficiency by taking advantage of the structural defects in MOFs, and could also inspire more work on the design of advanced defective MOFs.

Enhancing luminescence of intrinsic and Mn doped CsPbCl3 perovskite nanocrystals through Co2+ doping

Zhen Cao,Ji Li,Li Wang,Ke Xing,Xi Yuan,Jialong Zhao,Xin Gao,Haibo Li

In this work, the effects of Co 2+ ions on the structural and luminescent properties of intrinsic and Mn doped CsPbCl 3 NCs were studied by using photoluminescence (PL) spectroscopy, X-ray diffraction (XRD) spectroscopy, and transmission electron microscopy (TEM). The undoped and Mn doped CsPbCl 3 NCs with various Co/Pb molar ratios were synthesized at 190 °C. It was found that the quantum yields of purple emissions in these CsPbCl 3 NCs were greatly enhanced up to 30% after Co 2+ ions were doped. The diffraction peaks in XRD patterns shifted to a large angle with the increase of Co/Pb molar ratio, indicating Co doping in Pb-site. Further both intrinsic and Mn doped CsPbCl 3 NCs exhibited uniform cubes with average sizes of 8–10 nm and good crystallinity after Co doping. The enhancement of purple emissions from excitons in the CsPbCl 3 NCs was related to the reduction of nonradiative defects in these NCs through Co 2+ doping.

CO2 capture performance and characterization of cellulose aerogels synthesized from old corrugated containers

Yingju Miao,Hongchao Luo,Manoj Pudukudy,Yunfei Zhi,Wenbo Zhao,Shaoyun Shan,Qingming Jia,Yonghao Ni

Old corrugated containers with low recyclability were used as raw materials to synthesize a series of aerogels with varying cellulose concentrations in NaOH/urea solution via a freeze-drying process. The resulting aerogels had a rich porous structure with specific surface areas in the range of 132.72–245.19 m 2 .g −1 and mesopore volumes in the range of 0.73–1.53 cm 3 .g −1 , and were tested for CO 2 sorption at ambient temperature and pressure, displaying excellent CO 2 adsorption capacities in the range of 1.96–11.78 mmol.g −1 . Furthermore, the CO 2 /N 2 selectivity of aerogels decreased with decreasing specific surface area, which was mainly caused by the decrease in CO 2 capture. In addition, the CO 2 sorption capacity of the sample with 2% cellulose content, CA-2, exceeded the values reported so far for many other sorbents with higher specific surface areas, and showed reasonable cyclic stability for CO 2 capture. Therefore, this adsorbent represents an attractive prospect for CO 2 uptake at room temperature .

Temperature and CO2 Dual-Responsive Pickering Emulsions Using Jeffamine M2005-Modified Cellulose Nanocrystals

Gaihuan Ren,Xiaoyang Zheng,Hui Gu,Wenwen Di,Zengzi Wang,Yanlin Guo,Zhenghe Xu,Dejun Sun

Cellulose nanocrystals (CNCs) with excellent biodegradability are promising biomaterials for use as responsive Pickering emulsifiers. However, the high hydrophilicity of CNCs limits their emulsification ability. Some existing studies have utilized complicated covalent modification procedures to increase the hydrophobicity of CNCs. To simplify the modification process, we prepared hydrophobically modified CNCs (CNCs-M2005) via simple and controllable electrostatic interactions with thermosensitive M2005. The obtained CNCs-M2005 exhibited temperature and CO2 dual-responsive properties. Subsequently, stable oil/water Pickering emulsions were prepared using the partially hydrophobic CNCs-M2005 at 20 °C. However, demulsification occurred when the temperature increased to 60 °C. This temperature-induced demulsification resulted from the dehydration of polyethylene oxide and polypropylene oxide, causing the aggregation of the CNCs-M2005, as shown by dynamic light scattering and transmission electron microscopy experiments. In addition, demulsification was also achieved after bubbling CO2, which was attributed to the dissociation of the partially hydrophobic CNCs-M2005. The temperature and CO2 dual-responsive biosafe Pickering emulsions open up opportunity for the design of intelligent food, cosmetic, and drug delivery systems.

CO2-Responsive Nano-Objects with Assembly-Related Aggregation-Induced Emission and Tunable Morphologies

Liang Qiu,Haoran Zhang,Bo Wang,Yong Zhan,Chengfen Xing,Cai-Yuan Pan

CO2-responsive polymeric nano-objects with assembly-related aggregation-induced emission (AIE) are obtained via polymerization-induced self-assembly (PISA) of 2-(dimethylamino)ethyl methacrylate (DMAEMA), 2-(4-formylphenoxy)ethyl methacrylate (MAEBA), and 4-(1,2,2-triphenylvinyl)phenyl methacrylate (TPEMA). These nano-objects exhibit, depending on the feed of MAEBA, a morphology evolution process from spherical micelles to vesicles. Due to the presence of DMAEMA units, CO2 promotes morphology transformation of the nano-objects from spheres to a mixture of “jellyfish” and vesicles and vesicles to complex vesicles. Moreover, TPEMA endows the AIE feature to these nano-objects, offering a strategy to monitor the morphology evolution process in real time. Thus, this approach is significant for exploring the assembly mechanism of copolymer in polymerization-induced self-assembly and designing multistimuli-responsive polymeric nanomaterials with tunable morphologies and sizes.

CO2 absorption characteristics of amino group functionalized imidazolium-based amino acid ionic liquids

Sehee Kang,Yongchul G. Chung,Jo Hong Kang,Hojun Song

In this study, dual amino group functionalized imidazolium amino acid ionic liquids (AAILs) were synthesized from imidazole , bromoalkylamine, and amino acids. 1-(3-aminopropyl)-3-(2-aminoethyl)imidazolium hydroxide ([Apaeim][OH]), 1-propyl-3-(2-aminoethyl)imidazolium hydroxide ([Paeim][OH]), and 1-ethyl-3-(2-aminoethyl)imidazolium hydroxide ([Eaeim][OH]) were synthesized in two-steps, while [Apaeim][amino acid], [Paeim][amino acid], and [Eaeim][amino acid] were synthesized in three-steps. The structures of the synthesized AAILs were confirmed by 1 H NMR analysis. Moreover, the CO 2 absorption mechanism of [Apaeim][OH] was confirmed by FT-IR and 13 C NMR analyses. Subsequently, CO 2 absorption-desorption tests were conducted under at 15 vol% CO 2 , 313 K and atmospheric pressure. The cation and anion effects on the ionic liquid absorbents were also investigated. Among the tested ionic liquid solutions, 30 wt% [Apaeim][OH] and 30 wt% 1-(3-aminopropyl)-3-(2-aminoethyl)imidazolium alaninate ([Apaeim][ala]) displayed the best performances. Thus, both presented CO 2 cyclic capacities 2.2-fold higher than that of the benchmark CO 2 absorbent 30 wt% monoethanolamine (MEA), while their viscosities were comparable to that of 30 wt% MEA. Notably, 30 wt% [Apaeim][ala] show great potential as a CO 2 absorbent due to its high CO 2 cyclic capacity and low viscosity.

Porous hypercrosslinked polymer-TiO2-graphene composite photocatalysts for visible-light-driven CO2 conversion

Wang Shaolei,Xu Min,Peng Tianyou,Zhang Chengxin,Li Tao,Hussain Irshad,Wang Jingyu,Tan Bien

Significant efforts have been devoted to develop efficient visible-light-driven photocatalysts for the conversion of CO 2 to chemical fuels. The photocatalytic efficiency for this transformation largely depends on CO 2 adsorption and diffusion. However, the CO 2 adsorption on the surface of photocatalysts is generally low due to their low specific surface area and the lack of matched pores. Here we report a well-defined porous hypercrosslinked polymer-TiO 2 -graphene composite structure with relatively high surface area i.e., 988 m 2  g −1 and CO 2 uptake capacity i.e., 12.87 wt%. This composite shows high photocatalytic performance especially for CH 4 production, i.e., 27.62 μmol g −1  h −1 , under mild reaction conditions without the use of sacrificial reagents or precious metal co-catalysts. The enhanced CO 2 reactivity can be ascribed to their improved CO 2 adsorption and diffusion, visible-light absorption, and photo-generated charge separation efficiency. This strategy provides new insights into the combination of microporous organic polymers with photocatalysts for solar-to-fuel conversion.

CO2-switchable surfactant-free microemulsion consisted of N,N-dimethylcyclohexylamine, ethanol and water

Daixue Xu,Hongsheng Lu,Dongfang Liu,Xiaojiang Li

Safety-reinforced rechargeable Li-CO2 battery based on a composite solid state electrolyte

Wang Rui,Zhang Xuejing,Cai Yichao,Nian Qingshun,Tao Zhanliang,Chen Jun

The rechargeable Li-CO 2 battery has been receiving significant attention owing to its merits of high energy density and the efficient utilization of CO 2 . However, the widely application is plagued by severe security risks, such as leakage, flammability and lithium dendrites growth due to the use of liquid organic electrolytes. Here, a composite solid state electrolyte consisting of polyethylene oxide (PEO) and 20 wt.% Li 7 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) was prepared and first introduced into Li-CO 2 battery to solve the problems. The composite solid state electrolyte exhibited high ionic conductivity (1.03 × 10 −1 S·cm −1 at 70 °C), wide electrochemical window (5 V vs. Li + /Li), good mechanical properties and excellent flexibility. Ultimately, the Li symmetric cell with PEO/LLZTO composite solid state electrolyte can operate 1,500 h at a current density of 0.1 mA·cm −2 . The assembled all-solid-state Li-CO 2 battery behaved a long cycle life of 70 cycles at a current density of 100 mA·g −1 with fixed capacity of 1,000 mAh·g −1 . Our work provides new perspective to develop rechargeable all-solid-state Li-CO 2 batteries.

Metal (Ni2+/Co2+) sulfides modified BiVO4 for effective improvement in photoelectrochemical water splitting

Houde She,Man Jiang,Pengfei Yue,Jingwei Huang,Lei Wang,Jianzhang Li,Gangqiang Zhu,Qizhao Wang

The performance of BiVO 4 for photoelectrocatalytic (PEC) water decomposition is commonly limited by reaction kinetics. In this work, NiS and CoS nanospheres were respectively loaded on BiVO 4 thin films (NiS/BiVO 4 and CoS/BiVO 4 composites) to improve its reaction kinetics for PEC water decomposition. Both physical and chemical properties of these composites were characterized by XRD , SEM, TEM, PL and UV-DRS. The photoelectric properties of the samples were verified by testing LSV , i-t, EIS and IPCE. The formation of the composites can effectively prevent the recombination of carriers and consequently accelerate the separation of electrons and holes. NiS/BiVO 4 and CoS/BiVO 4 can reach photocurrent of 2.1 mA cm −2 and 2.7 mA cm −2 under light respectively, at 1.23 V vs. RHE, which are 1.75 times and 2.25 times that of BiVO 4 (1.2 mA cm −2 ). The hydrogen production of the NiS/BiVO 4 and CoS/BiVO 4 photoanodes was 4.7 and 7.3 times higher than that of BiVO 4 photoanode, respectively.

Enhanced performance of photocatalytic CO2 reduction via synergistic effect between chitosan and Cu:TiO2

Houde She,Ziwei Zhao,Wencai Bai,Jingwei Huang,Lei Wang,Qizhao Wang

Photocatalytic CO 2 reduction is considered as a feasible approach for solving greenhouse effect and energy shortage. Promoting electron migration and inhibiting electron-hole recombination are key challenges for efficient photocatalytic CO 2 reduction. Here, we successfully synthesized Cu:TiO 2 -CS composite as photocatalyst by a facile solvothermal method to improve the high-catalytic effect on CO 2 reduction. The as-prepared composite exhibits excellent photocatalytic CO 2 reduction performance under 300 W xenon lamp irradiation, with the yields of CO and CH 4 up to 4.48 μmol/g and 5.34 μmol/g, which is 10 times higher than that of TiO 2 . This impressive amelioration can be attributed to the synergy of organic polymer (chitosan) and inorganic material (Cu:TiO 2 ). This work may provide a constructing guidance in designing the composite photocatalyst concerning CO 2 photocatalytic reduction.

Metallic MoO2-Modified Graphitic Carbon Nitride Boosting Photocatalytic CO2 Reduction via Schottky Junction

Huang Jing Wei Li,Huimin Zhou,Kejun Chen,Kang Liu,Shi Li,Kexin Jiang,Wenhao Zhang,Yanbo Xie,Zhou Cao,Hongmei Li,Hui Liu,Xiaowen Xu,Hao Pan,Junhua Hu,Dongsheng Tang,Xiaoqing Qiu,Junwei Fu,Min Liu

Directly using solar energy to realize photocatalytic reduction of CO 2 to hydrocarbon fuels is an effective tactics to solve the energy crisis and carbon emission. Although graphite carbon nitride (g-C 3 N 4 ) has been widely studied as a star photocatalyst for CO 2 reduction, the extremely fast charge recombination rate seriously limits its performance. Loading suitable co-catalysts to construct an effective junction is considered an efficient way to solve this issue and promote photocatalytic performance. In this work, metallic molybdenum dioxide (MoO 2 ) is dispersed on g-C 3 N 4 nanosheets to construct a Schottky junction photocatalyst. The Schottky junction between MoO 2 and g-C 3 N 4 induces efficient charge separation and transfer. As a result, the optimal MoO 2 /g-C 3 N 4 Schottky junction photocatalyst exhibits a 15 times higher CH 4 yield and five times higher CO yield compared with pure g-C 3 N 4 . This article provides a new route to construct a Schottky junction for boosting photocatalytic activity.