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"There is an abundant source of naturally occurring mordenitein the Bayah region of Indonesia. In this work we studied how acid dealumination of this indigenous zeolite affected its physical, chemical and catalytic properties. The results are compared to those obtained with another natural mordenite and a commercially available synthetic mordenite. Acid dealumination of mordenites is known to affect the pore structure and therefore enhance the adsorption-properties of the zeolite and the accessibility to its acidic sites. A series of dealuminated mordenite samples were prepared. They were refluxed in constant boiling HCl as a function of time. The samples were each subsequently exchanged with IN ammonium nitrate. The Si/Al ratio was determined by X-Ray Fluorescence. The presence of other metals was detected with Atomic Adsorption Spectroscopy and Inductively Coupled Plasma Spectroscopy. Nitrogen Adsorption was used to determine the surface area and the pore size distribution. Crystallinity and unit cell size were determined via X-Ray Diffraction. The surface morphology was probed with Scanning Electron Microscopy. An n-hexane cracking test was utilized to probe catalytic activity and selectivity. The results of this study indicate that up to and including sixteen hours of reflux, dealumination of this natural Indonesian mordenite increases the crystallinity and the average pore size, however the surface area and the unit cell size remain constant. Additional reflux, beyond sixteen hours, destroyed a portion 'of the zeolitic framework, indicated by a loss in crystallinity. Cracking activity increased through sixteen hours .of ref lux and was found to be constant thereafter. Total' C2, C3 and C4 {including isobutene) selectivity improved through sixteen hours of reflux and then also remained constant. In comparison to a commercially available sample of synthetic mordenite, the modified Indonesian mordenite ,is less active, but has comparable selectivity. However, compared to the naturally occuring U.S. mordenite, the modified Indonesian mordenite has improved physical and catalytic properties."

"Among semiconductors, zinc oxide (ZnO) has received great attention due to its wide band-gap and high electron mobility, resulting in various strategic applications. Controlling the physical properties of ZnO is therefore a critical issue in the fabrication of related electronic and optical devices. In this study, ZnO nanorods layers were grown on an ITO glass substrate via chemical bath deposition at low temperature. Prior to the growing process, the layers were deposited using a spin-coating technique. The seeding solution was made by dissolving zinc nitrate tetrahydrate and hexamethylene tetraamine in cold water (0oC) for an hour using a cooler bath. The as-synthesized ZnOs were further subjected to different post-hydrothermal treatment series at a temperature of 150oC for three hours at atmospheric pressure and at 100°C for one hour under one bar of nitrogen gas (N2) pressure. The characterization was performed using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and UV-Vis spectroscopy. The SEM results showed that the ZnO nanorods were grown as a vertically aligned hexagonal structure, while the XRD patterns showed a high intensity at the (002) plane. On the basis of investigation, it was found that under post-hydrothermal treatment at 150oC for three hours with atmospheric pressure, the synthesis procedure resulted in nanostructures in the form of ZnO rods. Meanwhile, post-hydrothermal treatment at 100°C for one hour under one bar of nitrogen gas (N2) produced ZnO rods and tubes. In general, the post-hydrothermal process provided a high degree of crystallinity. The optimum ZnO layer was obtained after post-hydrothermal treatment at 150oC for three hours at atmospheric pressure, with a crystallite size and band-gap energy of ~18 nm and 3.20 eV, respectively."

"Selama beberapa dekade terakhir, upaya luar biasa telah dilakukan untuk mengembangkan fotokatalis seperti oksida logam terner yang tidak beracun dan murah, mis. CuBi2O4 (CBO). Namun demikian, aplikasi skala besar dari bahan tersebut masih terhalang oleh pemisahan muatan fotogenerasi yang buruk. Oleh karena itu, peningkatan aktivitas fotokatalitik CBO akan dilakukan dengan memodulasi kekosongan oksigen (VO). Pada penelitian ini, modulasi kekosongan oksigen (VO) pada CBO dilakukan dengan metode reduksi kimia sederhana. Di sini, modulasi dievaluasi dengan memvariasikan jenis zat pereduksi. Struktur kristal dicirikan oleh Difraktometri Sinar-X dan sifat spektroskopi yang dicirikan dengan DRS uv-vis, Spektroskopi Photoluminescence dan Spektroskopi Raman.

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During the past several decades tremendous efforts have been made to develop photocatalysts such as a non-toxic and cheap ternary metal oxide, e.g. CuBi2O4 (CBO). Nevertheless, large scale application of such material is still hindered by its poor photogenerated charge separation. Therefore, enhancement of CBO photocatalytic activity will be carried out by modulating its oxygen vacancy (VO). In this work, the modulation of oxygen vacancy (VO) in CBO had been done by simple chemical reduction method. Here, the modulation evaluated by varying the type reducing agents. The crystal structures characterized by X-Ray Diffractometry and the spectroscopic properties characterized with uv-vis DRS, Photoluminescence Spectroscopy and Raman Spectroscopy."