A solution combustion process for the synthesis of hollandite (BaAl2Ti6O16) powders is described. SYNROC (synthetic rock) consists of four main titanate phases: perovskite, zirconolite, hollandite and rutile. Hollandite is one of the crystalline host matrices used for the disposal of high-level radioactive wastes because it immobilizes Sr and Lns elements by forming solid solutions. The solution combustion synthesis, which is a self-sustaining oxi-reduction reaction between a nitrate and organic fuel, generates an exothermic reaction and that heat converts the precursors into their corresponding oxide products in air. The process has high energy efficiency, fast heating rates, short reaction times, and high compositional homogeneity. To confirm the combustion synthesis reaction, FT-IR analysis was conducted using glycine with a carboxyl group and an amine as fuel to observe its bonding with metal element in the nitrate. TG-DTA, X-ray diffraction analysis, SEM and EDS were performed to confirm the formed phases and morphology. Powders with an uncontrolled shape were obtained through a general oxide-route process, confirming hollandite powders with micro-sized soft agglomerates consisting of nano-sized primary particles can be prepared using these methods.

The ZnO–Na2Ti6O13 composites were synthesized by facile solution combustion method with different molar concentrations of sodium titanate which is prepared by hydrothermal route. The formation of the composites was confirmed by the X-ray diffraction (XRD) analysis. Field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) results revealed that the synthesized composites exhibit porous morphology, whereas the pristine Na2Ti6O13 nanoparticles have whisker like morphology. Diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) studies were utilized to compute the bandgap and the presence of defects in the composites respectively. The photocatalytic activity of ZnO–Na2Ti6O13 catalyst was investigated through the degradation of 4-nitrophenol under solar light over a period of 180 min and the composite with 0.05 M of Na2Ti6O13 showed higher degradation efficiency (96%) than the other concentrations of Na2Ti6O13 and pristine ZnO. The reduced bandgap, high charge transfer, more oxygen vacancies and the production of high superoxide anion radicals have profound effect on the higher photocatalytic efficiency of the composite with 0.05 of M Na2Ti6O13.

Amorphous agglomerates of carbon nanospheres (CNS) with a diameter range of 10-50 nm were synthesized using the solution combustion method. High-resolution transmission elec-tron microscopy (HRTEM) revealed a densely packed high surface area of SP2-hybridized carbon; however, there were no crystalline structural components, as can be seen from the scanning electron microscopy, HRTEM, X-ray diffraction, Raman spectroscopy, and ther-mal gravimetric analyses. Electrochemical and thermo catalytic decomposition study results show that the material can be used as a potential electrode candidate for the fabrication of energy storage devices and also for the production of free hydrogen if such devices are used in a fluidized bed reactor loaded with the as-prepared CNS as the catalyst bed.

LaFeO3 powders were synthesized using a method involving solution combustion, and the surfaceproperties of these powders were examined by x-ray photoelectron spectroscopy. As the amount of fuelincreased during the synthesis, the LaFeO3 powders became amorphous with a large plate-like shape. It wasfound that the O 1s spectra were composed of two types of photoelectrons by deconvolutioning the spectra.Photoelectrons with higher binding energy come from adsorbed oxygen (O−) whereas those with lower energycome from lattice oxygen (O2−). The ratio of adsorbed and lattice oxygen increased as the ratio of the fuel andnitrate (Φ) increased. The binding energy of both types of oxygen increased as Φ increased due to the formationof carbonates.

착체증합법 및 연소합성법에 의해 Zn0.994Mn0.006Ga2O4녹색형광체 분말을 합성하였으며, 이들의 분말 및 발광특성을 XRD, SEM, BET, PL 등을 사용하여 조사하였고, 이를 고상반응법에 의하여 합성한 시료와 비교하였다. 착체중합법과 연소합성법에 의해 합성한 시료는 각각 500˚C와 400˚C에서 단일 스피텔 상이 생성되었으며, 이들의 입자크기는 고상반응에 의해 합성된 분말에 비하여 작았다. 한편, 착체중합법에 의하여 합성한 분말의 발광강도는 열처리 온도가 900˚C일 때, 연소합성법에서는 반응온도가 400˚C일 때 각각 최대값을 나타내었다.

이 연구에서는 알코올과 증류수를 특정비율로 혼합한 특수용매를 사용하여 합성한 Gd2O3:Eu 나노 분말이 Europium(Eu)함량에 따라 어떤 입자특성과 발광특성을 가지게 되는지에 대하여 조사하였다. 액상법에 사용된 이 용매는 Gadolinium(Gd)과 Europium(Eu)의 용해되는 시간을 현저히 줄임으로써, 실험시간이 단축됨을 확 인하였다. 이번 실험에서 Gd2O3:Eu 나노 powder 형광체의 입자특성은 SEM(scanning electron microscope)과 EDX(Energy Dispersive X-ray)를 사용하였으며, 나노 powder의 발광특성은 PL(Photoluminescence), CL(CathodeLuminescence)을 사용하여 측정하였다. 결정들은 30nm∼40nm의 크기의 결정을 가졌고 발광특성 은 약 620nm의 특정 파장에서 크게 반응함을 알 수 있었으며, Europium(Eu)함량이 1wt%에서 3wt%, 5wt% 로 늘어날수록 Photon의 count가 증가하게 되어 발광효율이 증가함을 알 수 있었다.