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Direct transfer of the CVD-grown graphene on copper foils on SiO2 substrate under supercritical CO2 assisted-cleaning technique
摘要： The transfer of CVD-grown graphene sheets onto arbitrary substrates is important for the development of practical applications. Unfortunately, designing a low cost and highly efficient graphene transfer technique to achieve defect-free graphene sheets with low contact resistance onto various substrates still remains a challenge. In this paper, a CVD grown monolayer graphene sheet was directly transferred on SiO2/Si substrate. We found that a combination of floating copper with graphene films on ammonium persulfate solution with an original method of supercritical CO2 fluid can effectively produce clean and dry samples without damaging the crystalline quality of graphene. This method does not require any polymeric material to be desposited on the graphene films at any stage. Samples are analyzed by optical microscopy, Raman spectroscopy, scanning electron microscopy and atomic force microscopy. This method is very promising for cleaning graphene samples for electronic device fabrication.
关键词： transfer technique,supercritical CO2,SiO2 substrate,graphene,CVD
更新于2025-09-23 15:19:57
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Supercritical CO <sub/>2</sub> -assisted deposition of NiO on (101)-anatase-TiO <sub/>2</sub> for efficient facet engineered photocatalysts
摘要： NiO/(101)-anatase-TiO2 heterostructure nanoparticles were synthesized by depositing NiO onto the (101) facet of anatase crystals via the supercritical fluid chemical deposition (SFCD) route. Thorough characterization experiments performed by various techniques (XRD, UV-Vis DRS, N2 sorption, HR-TEM, EDX, and XPS) indicate that the SFCD method allowed a good dispersion of NiO onto the TiO2 nanoparticles for NiO amounts below 2 wt%. Compared to pure TiO2, the 0.1–1 wt% NiO–TiO2 nanocomposites showed enhanced photocatalytic properties for methylene blue (MB) and methyl orange (MO) decomposition under UV light irradiation, the 0.25 wt% NiO–TiO2 system leading to the highest efficiencies. The photocatalytic properties were then rationalized in terms of the acidic properties and electronic structures of the NiO–TiO2 nanocomposites. This higher photocatalytic activity was mainly related to the heterocontact at the interface of the NiO–TiO2 crystallites and to the enhanced reaction rates at the NiOx surface.
关键词： anatase-TiO2,Supercritical CO2,photocatalysis,NiO deposition,facet engineering
更新于2025-09-19 17:15:36
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Enhanced Performance and Stability of Ternary Organic Solar Cells Utilizing Two Similar Structure Blend Fullerene‐Free Molecules as Electron Acceptor
摘要： Two-dimensional amorphous semiconductor (2DAS) monolayers can be regarded as a new phase of 2D monolayers materials and will serve as a promising field for the various electronic and optoelectronic applications. Here, together with the first-principles calculations within density functional theory, we experimentally demonstrate that the 2DAS MoO3-x monolayers can enhance the electrochemical nitrogen reduction reaction (NRR). To be specific, the NH3 yield and faradaic efficiency (FE) reach 35.83 ug h-1 mg-1 cat at -0.40 V and 12.01 % at -0.20 V vs. reversible hydrogen electrode (RHE), respectively, and which can be dramatically improved than that of reported defective MoO3 nanosheets. Further theoretical calculations reveal that the high electrochemical performance in NH3 yield is contributed to the strong Anderson localization and electron confinement dimensionally. And such Anderson tail states can resonate effectively with the states of intermediate HNNH, playing the critical role in the rate limiting step of NRR. Integrated experimental findings and theoretical understanding, a new concept of Anderson confinement catalysis is put forward, and could be extended to other 2DAS for potential catalytic reactions.
关键词： Anderson localization,amorphous,nitrogen reduction reaction,molybdenum oxides,supercritical CO2
更新于2025-09-19 17:13:59
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Controlled transition of microcapsules from coil conformation to globule during the expansion of the pulse jet of nanoparticle suspension of TiO2 in supercritical (CO2) polyethylene glycol solution
摘要： The process of microencapsulation of titanium dioxide nanoparticles during the expansion of a supersonic jet of TiO2 suspension in a solution of polyethylene glycol (PEG 8000) in supercritical CO2 into a vacuum and background gas (helium) has been studied experimentally. The dependence of the position of the microcapsule transition point on the jet axis from the coil to a globular conformation on the temperature in the reactor and on the pressure of the background gas at different co-solvent concentrations has been established. A “coil?globule” re-entrant transition has been recorded at a greater distance from the nozzle exit than the point of collapse.
关键词： supersonic jet,polyethylene glycol,microencapsulation,supercritical CO2,coil-globule transition,titanium dioxide
更新于2025-09-12 10:27:22