Facile growth of aluminum oxide thin film by chemical liquid deposition and its application in devices

Uniform and continuous Al2O3 thin films were prepared by the chemical liquid deposition (CLD) method. The breakdown field strength of the amorphous CLD-Al2O3 film is 1.74 MV/cm, making it could be used as a candidate dielectric film for electronic devices. It was further proposed to use the CLD-Al2O3 film as an electron blocking layer in a triboelectric nanogenerator (TENG) for output performances enhancement. Output voltages and currents of about 200 V and 9 µA were obtained, respectively, which were 2.6 times and 3 times, respectively, higher than TENG device without an Al2O3. A colloidal condensation-based procedure controlled by adjusting the pH value of the solution was proposed to be the mechanism of CLD, which was confirmed by the Tyndall effect observed in the growth liquid. The results indicated that the CLD could serve as a low-cost, room temperature, nontoxic and facile new method for the growth of functional thin films for semiconductor device applications.

Effects of Steaming and SiO2 Surface Passivation on SSZ-13 Zeolites in the Ethylene to Propylene Reaction

SSZ-13 zeolite was modified by two kinds of post-treatment methods such as steaming and SiO2 surface passivation (silylation) for ETP catalyst with high activity. The former steaming treatment was conducted in the range of 400–700 °C, whereas the latter surfaces passivation was applied to a chemical liquid deposition (CLD) technique that uses various silylation agents such as tetramethylorthosilicate (TMOS), tetraethylorthosilicate (TEOS), and tetrabuthylorthosilicate (TBOS). Catalysts were characterized by powder-XRD, ICP, Ar-phsisorption, solid-state 27Al MAS NMR, and NH3-TPD, and their activities were tested in fixed bed reaction system. Regarding the effects of steaming temperature, the results show that a relatively higher selectivity is observed in SSZ-13 catalysts treated at proper steaming temperatures such as 450 and 500 °C compared to parent and other steam treated catalysts. For optimum surface passivation treatments for ETP reactions, one-step surface passivation using TEOS agents among various passivation agents led to enhanced propylene selectivity to 80% when compared with parent and other silylated SSZ-13 catalysts. However, a sequential passivation treatment with a TEOS agent was not highly affected by the reaction activity.

Synthesis and characterization of Fe, Co, and Ni colloids in 2-mercaptoethanol

Metal colloids in 2-mercaptoethanol using nanoparticles (NPs) of iron (Fe), cobalt (Co), and nickel (Ni) were prepared by chemical liquid deposition method. Transmission electron microscopy, electron diffraction, UV-VIS spectroscopy, and scanning electron microscopy with electron dispersive X-ray spectroscopy characterized the resulting colloidal dispersions. The NPs exhibited sizes with ranges from 9.8 nm for Fe, 3.7 nm for Co, and 7.2 nm for Ni. The electron diffraction shows the presence of the metals in its elemental state Fe (0), Co (0), and Ni (0) and also some compounds FeO (OH), CoCo2S4, and NiNi2S4.

Insights into the Nature of Hydroxyl Groups and Zn Species over Defective HZSM-5 Zeolite Supported Zinc Catalysts Prepared by Chemical Liquid Deposition (CLD) with Zn(CH2CH3)2

A series of defective ZSM-5 zeolites (~300 nm, SiO2/Al2O3 ratio of 55, 100, 400 and 950) were intentionally prepared and systematically studied by XRD, SEM, 29Si MAS NMR, argon physisorption, NH3-TPD and FT-IR technologies. The nature, the amount and the accessibility of the acid sites of defective ZSM-5 zeolites are greatly different from reported ZSM-5 zeolites with perfect crystal structure. The co-existed strong Brønsted acid sites (Si(OH)Al) and weak Brønsted acid sites (hydroxyl nests) over defective ZSM-5 zeolites might lead to unique catalytic function. Zn(C2H5)2 was grafted onto defective ZSM-5 zeolites through chemical liquid deposition (CLD) method. Interestingly, FT-IR spectroscopy studies find that Zn(C2H5)2 was preferentially grafted on the hydroxyl nests with weak acidity rather than the Si(OH)Al groups with strong acidity over different defective ZSM-5 zeolites. Particularly, home-built operando dual beam FTIR-MS was applied to study the catalytic performance of Zn species locating at different sites of defective ZSM-5 zeolites under n-hexane transformation. Results show that Zn species grafted over hydroxyl nests obtain better dehydrogenation performance than Zn species over framework aluminum. This study provides guidance for the rational design of highly efficient alkane dehydrogenative aromatization catalysts.