Energies
·
2020
·Vol. 13
·期 4
·846
·
IF 2.702
Changzhou Chen,Peng Liu,Minghao Zhou,Brajendra K. Sharma,Jianchun Jiang
Transfer hydrogenation is a novel and efficient method to realize the hydrogenation in different chemical reactions and exploring a simple heterogeneous catalyst with high activity is crucial. Ni/CNT was synthesized through a traditional impregnation method, and the detailed physicochemical properties were performed by means of XRD, TEM, XPS, BET, and ICP analysis. Through the screening of loading amounts, solvents, reaction temperature, and reaction time, 20% Ni/CNT achieves an almost complete conversion of phenol after 60 min at 220 °C in the absence of external hydrogen. Furthermore, the catalytic system is carried out on a variety of phenol derivatives for the generation of corresponding cyclohexanols with good to excellent results. The mechanism suggests that the hydrogenation of phenol to cyclohexanone is the first step, while the hydrogenation of cyclohexanone for the generation of cyclohexanol takes place in a successive step. Moreover, Ni/CNT catalyst can be magnetically recovered and reused in the next test for succeeding four times.Keywords:phenol;hydrogenation;Ni/CNT;cyclohexanol;transfer hydrogenation
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
ACTA PHYSICO-CHIMICA SINICA
·
2023
·
IF 10.9
Kezhen Lai,Fengyan Li,Ning Li,Yangqin Gao,Lei Ge
Hydrogen is an important zero-pollution green energy source with potential for alleviating environmental contamination and energy shortages. Hydrogen evolution via solar-energy-induced semiconducting water splitting is among the most environmentally friendly methods available to date. In this study, a metal–organic-framework-derived, Ni-decorated carbon nanotube (Ni-CNT) is used as a non-noble co-catalyst. This Ni-CNT is grown in situ on ZnIn 2 S 4 nanosheets using a simple one-step oil bath strategy, wherein Ni nanoparticles are wrapped around the top and cross sections of the nanotubes, preventing their agglomeration. Notably, Ni-CNT/ZnIn 2 S 4 heterostructures feature intimate contact interfaces that promote charge transfer, facilitating their use as efficient photocatalysts for hydrogen evolution. The 38Ni-CNT/ZnIn 2 S 4 sample exhibits a high H 2 production rate (12267 μmolꞏh −1 ꞏg −1 ), with an apparent quantum efficiency (AQE) of 11.3% under 420 nm monochromatic light irradiation, which is nearly 6.4 times that of pure ZnIn 2 S 4 . The results of X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) corroborate the observations on Ni-CNT/ZnIn 2 S 4 heterostructures. Electrochemical measurements reveal that the combination of the Ni-CNT and ZnIn 2 S 4 facilitates the transfer of photogenerated electrons and effectively prevents rapid recombination of photocarriers, thus improving the hydrogen evolution performance of ZnIn 2 S 4 . Electron spin resonance (ESR) results further prove that cocatalyst Ni-CNTs are beneficial for prolonging the lifetimes of ZnIn 2 S 4 photogenerated electrons, thereby achieving effective charge separation. A charge transfer pathway in the heterojunction interfaces is further explored and confirmed by density functional theory (DFT) calculations. The difference in the Fermi level energy ( E f ) contributes to both charge migration and the generation of a built-in electronic field (BEF), indicating that the energy band of ZnIn 2 S 4 bends downward, which is favorable for photogenerated electron flow from ZnIn 2 S 4 to the Ni-CNT electron acceptor. The results of planar-averaged electron density difference analysis confirm that the hot electrons are transferred from Ni nanoparticles to the CNT and then to the ZnIn 2 S 4 nanosheets, indicating the formation of a photogenerated electron transfer pathway of ZnIn 2 S 4 → CNT → Ni. Furthermore, Gibbs free energy of H* adsorption (Δ G H* ) and crystal orbital Hamilton population (COHP) analysis indicate that Ni nanoparticles can serve as active sites, promoting H 2 evolution. Thus, the present study formulates a new strategy for developing low-cost, high-efficiency, non-noble-metal co-catalysts for photocatalytic hydrogen production. Download: Download high-res image (88KB) Download: Download full-size image
研究领域:
材料科学
·
能源化学
·
环境科学
✓ 已验证
DOI
高影响因子
CATALYSIS COMMUNICATIONS
·
2023
·
IF 3.7
Shengzhe Wang,Hongxia Lv,Chengyu Jin,Yu Wang,Huangzhao Wei,Chenglin Sun,Lian Yu,Lei Ma,Xiangnan Li,Xiaowei Liu
We synthesized a series of Ru-Ti-Ni/CNT electrodes to degrade levofloxacin in wastewater. The unique structure of Ni single-atom-kernelled Ru nanoparticles regulates the reaction process, producing a notable synergistic effect. The reaction kinetics constant of Ru-Ti-Ni/CNT with a Ru: Ti ratio of 10:0 outperforms Ni/CNT by 3.7 times and CNT alone by 16.4 times. Comprehensive characterizations revealed its morphology and structure nature. Ru nanoparticles can shield Ni, while Ni single-atom facilitates electron transfer in Ru nanoparticles, generating abundant reactive oxygen radicals (ROS) that degrade pollutants.
研究领域:
环境科学
·
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
SENSORS
·
2018
·Vol. 18
·期 10
·3493
·
IF 2.475
Yingang Gui,Xiaoxing Zhang,Peigeng Lv,Shan Wang,Chao Tang,Qu Zhou
SF6decomposition components detection is a key technology to evaluate and diagnose the insulation status of SF6-insulated equipment online, especially when insulation defects-induced discharge occurs in equipment. In order to detect the type and concentration of SF6decomposition components, a Ni-modified carbon nanotube (Ni-CNT) gas sensor has been prepared to analyze its gas sensitivity and selectivity to SF6decomposition components based on an experimental and density functional theory (DFT) theoretical study. Experimental results show that a Ni-CNT gas sensor presents an outstanding gas sensing property according to the significant change of conductivity during the gas molecule adsorption. The conductivity increases in the following order: H2S > SOF2> SO2> SO2F2. The limit of detection of the Ni-CNT gas sensor reaches 1 ppm. In addition, the excellent recovery property of the Ni-CNT gas sensor makes it easy to be widely used. A DFT theoretical study was applied to analyze the influence mechanism of Ni modification on SF6decomposition components detection. In summary, the Ni-CNT gas sensor prepared in this study can be an effective way to evaluate and diagnose the insulation status of SF6-insulated equipment online.Keywords:SF6decomposition components;carbon nanotube sensor;Ni modification;adsorption;DFT calculations
研究领域:
材料科学
·
电气工程
·
理论化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CARBON
·
2024
·
IF 10.5
Jun Weng,Yanan Liu,Xiaoxiao Huang
Metal-Organic framework (MOF) derivatives have been applied as electromagnetic wave absorption (EMA) materials in recent years. Carbon nanotubes (CNTs) can achieve in situ growth on the surface of MOF derivatives. However, there is limited research on the EMA performance by regulating the morphology of the in situ grown CNTs. In this work, we prepared MOF-derived Ni@carbon nanotubes (Ni@CNT) with controllable length of CNTs by solvothermal and simple one-step pyrolysis method and revealed the CNT growth mechanism. We further investigated the effect of in situ grown CNT morphology on electromagnetic parameters and EMA performance. In situ grown CNTs of similar length on the surface of MOF derivatives lead to similar electromagnetic parameters. When the length of CNTs is short, the relaxation strength ( Δ ε = ε s − ε ∞ ) is high, leading to excellent microwave absorption performance. For Ni@CNT-600, the reflection loss of −44.4 dB can be achieved at merely 1.72 mm. Finite element (FE) simulation was used to evaluate the EMA mechanism of different samples by calculating electric field and polarization strength. This work has explored the electromagnetic wave absorption performance from the perspective of microstructural tailoring, helpful for understanding the unique role of the in situ grown CNTs on the surface of MOF derivatives and investigating the ultra-thin electromagnetic wave absorption materials.
研究领域:
材料科学
·
电磁学
✓ 已验证
DOI
高影响因子
COMPOSITES SCIENCE AND TECHNOLOGY
·
2022
·
IF 9.879
Mengyuan Hao,Xin Qian,Yonggang Zhang,Jiaming Yang,Chunjie Li,Haoting Gong,Xuefei Wang,Piaopiao Wang,Li Liu,Yudong Huang
Owing to high graphitization degree, polyacrylonitrile (PAN)-based high modulus carbon fiber (HMCF) can not only be used as the general structural reinforcement for advanced composites, but also be applied to improve the thermal conductivities (TC) of polymer composites . However, the enhancement of through-thickness TC of composites remains extremely challenging due to fiber anisotropy and the lack of continuous thermal conductive path among CFs. In the present work, three-dimensional (3D) hybrid thermal conductive structures were constructed onto PAN-CF surfaces to prepare HMCF/epoxy composites with high through-thickness TC. In details, crosslinked high thermal conductive Ni/CNT hybrid network was firstly electrodeposited onto HMCF surfaces, which also provided abundant channels for the impregnation of easily graphitized poly-p-phenylene benzobisoxazole (PBO)/graphene oxide (GO). The freeze-drying assisted grafting of 3D-oriented PBO/GO and high-temperature heat treatments were further conducted to create the 3D graphite structures onto CFs. The interconnected Ni/CNT networks with 500 nm thickness and 3D aligned PBO-graphite bridging structures with an average thickness of 1 μm contributed to the formation of efficient heat conduction pathways along the through-thickness direction. Additionally, high-temperature treatment had been proven critical to effective heat conductions. Especially, PAN-CF with the 3D hybrid thermal conductive structures treated at 2100 °C (named CNC@PG-2100) exhibited superior TC, and the maximum TC value of CNC@PG-2100 reinforced composites reached 5.39 W/(m‧K) at the CF loading of 55%, which improved by 573% compared to that of composites reinforced by untreated PAN-CFs (0.94 W/(m‧K)).
研究领域:
材料科学
·
复合材料
·
热工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）