Abstract

Rudy Situmeang¹, R. Supryanto¹, Lolita N. Albert Kahar¹, Wasinton Simanjuntak¹ and Simon Sembiring²

DOI : http://dx.doi.org/10.13005/ojc/330415

In this study, nano-sizeLaCrO₃ was prepared through sol-gel route using pectin as emulsifying agent, followed by freeze – drying to obtain solid sample. The sample was prepared by mixing the solution of La(NO₃)₃.6 H₂O and Cr(NO₃)₃.9 H₂O with  pectin solution under magnetic stirring.  The sample was frozen and subsequently subjected to freeze – drying and calcination treatment at temperatures of 600, 700 and 800 ºC for 6 h.  The calcined samples were characterized with several techniques.  The phase composition was evaluated using the X-ray diffraction (XRD) technique, followed by crystallite size calculation using Scherrer Methods.  The functionality of sample was identified using Fourier transform infrared(FTIR) spectroscopy, surface structurein three dimensional images was analyzed using Transmission electron microscopy  (TEM), and particle size distribution was determined by Particles Size Distribution (PSA). The results of XRD characterization indicated that materials consist of various crystalline phases, with LaCrO₃ as a major phase.  FTIR Analysis revealed the existence of both Lewis and BrØnsted – Lowry acid sites, with Lewis acid as the prominent sites, represented by the absorption band located at around 1636 cm^-1. The samples were found to display relatively homogeneous surface morphology, having the crystallite size in the range of 24 to 25 nm according to  Scherrer equation.The PSA analyses revealed increased relative percentages of nano-size portion in the sample from 22 to 89% as temperatures increased from 600 to 800 ºC, with the particle size in the range of 30 to 35 nm as seen by the TEM .

perovskite; sol-gel; freeze-drying; pectin; acid sites

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