Synthesis of Polycrystalline CuCrO2 Using Sol-Gel and Solid-State Reaction Method
Nurul Maulida Rahmahyani Nst (a), Syahrul Humaidi (a*), Agung Imaduddin (b), Doli Bonardo (c), Heri Nugraha (d), Satrio Herbirowo (b), Nono Darsono (b)

(a) Department of Physics, FMIPA, Universitas Sumatera Utara, Jl. Bioteknologi I Kampus USU, Medan, Sumatera Utara, 20155, Indonesia
*syahrul1[at]usu.ac.id
(b) Research Center for Advanced Materials, National Research and Innovation Agency (BRIN), Tangerang Selatan, Banten, 15314, Indonesia
(c) Refrigeration and Air Conditioning Engineering Study Program, Politeknik Tanjungbalai, Jl. Sei Raja, Sei Tualang Raso, Tanjungbalai, 21345, Indonesia
(d) Research Center for Energy Conversion and Conservation, National Research and Innovation Agency (BRIN), Tangerang Selatan, Banten, 15314, Indonesia

Abstract

CuCrO_{2} has a delafossite-structure that has a potential to be a thermoelectric material. In this study, we synthesize polycrystalline CuCrO_{2} using sol-gel and solid-state reaction method. Urea self-combustion reaction has been used to get CuCrO_{2} phase on low temperature for sol - gel method. In this method, a precursor solution was prepared by mixing urea with an aqueous solution of blended (Cu-Cr) metal-nitrates in their stoichiometric ratios. The urea-mixed precursor solution was first heated in beaker to evaporate excess water and dried in the oven at 300 ^oC for 3 h. The resulting powder was calcined and pressed into pellet of 10 mm diameter and then sintered at 1100 ^oC for 10 h. Solid state reaction method, stoichiometric calculation of CuO and Cr_{2}O_{3} powders were used as starting materials. These powders were calcined at 1000 ^oC for 10 h. The calcined powders were pressed into pellet of 10 mm diameter and then sintered at 1050 ^oC for 10 h. The morphology of samples showed grain size of sol-gel method was smaller than solid state method and from EDX map evidence the presence of Cu, Cr, and O all over the samples. Based on XRD the samples with solid-state method have a single phase of CuCrO_{2} with FWHM (Full Width Half Maximum) value of 0.182 at the main peak, where the samples with sol-gel method still appeared impurities peak and FWHM value of 0.161. These results showed solid state method led the forms of single phase, bigger particle size, higher composition and better crystallization of CuCrO_{2}.

Keywords: CuCrO2- Delafossite structure- Sol-gel- Solid-State Reaction

Topic: Materials Sciences: Synthetic and Characterization