PREPARATION of Gd2O3 NANOMATERIALS via SOLUTION COMBUSTION SYNTHESIS FOR OXIDATIVE COUPLING OF METHANE

Abstract

In this study, in the production of Gd2O3 material which has many usage areas, solution combustion synthesis was used and the changes in the physical and structural properties of the material were investigated by changing the oxidant/fuel ratio. The resulting metal oxide powders were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, Thermogravimetric-Differential thermal analysis (TG-DTA) and scanning electron microscopy (SEM) analysis and tested in oxidative coupling of methane. Cubic and monoclinic phases were observed in Gd2O3 crystal structure at fuel-rich and stoichiometric conditions, and only cubic phase was determined at fuel-lean conditions. It was determined that the obtained powders were mesoporous and the highest BET surface area was obtained at stoichiometric oxidant/fuel ratio (18.6 m 2 /g). It was determined that the powders were formed from rather small particles (<35 nm) and with layered or stacked structure. The catalytic performance of Gd2O3 nanoparticles was found to be dependent on the BET surface area and crystal structure. The highest C2 yield (8.5%) was obtained at 720°C with the Gd2O3 that was synthesized using the equivalence ratio of 0.5.

İtriyum Katkılı Gadolinyum Oksit Numunelerinin Sentez ve Karakterizasyonu

“…Gd2O3, yüksek termal direnci ve yüksek yüzey alkalinitesi nedeniyle oksidasyon reaksiyonlarında katalizör olarak kullanılmasının yanında genellikle destek yapısı veya katkı maddesi olarak da kullanılmaktadır. Destek olarak kullanılacak gadolinyum oksidin yüksek yüzey alanına ve yüksek kristalleşmeye sahip olması önemlidir [5]. Gd2O3,Gd izotoplarının yüksek nötron yakalama tesir kesiti nedeniyle en düzenli olarak kullanılan yanabilir absorplayıcılardan biridir [6].…”

“…Gd2O3parçaçıkların sentezlenmesinde poliol, hidrotermal, sol-jel, mekanokimyasal, kimyasal çöktürme, darbeli lazer ablasyonu ve darbeli elektron ışını buharlaştırması gibi birçok yöntem kullanılmaktadır [4,5,[8][9][10][11].…”