Facile Microwave-Assisted Hydrothermal Synthesis of CuO Nanomaterials and Their Catalytic and Electrochemical Properties

Abstract

Copper oxides have been widely used as catalysts, gas sensors, adsorbents, and electrode materials. In this work, CuO nanomaterials were synthesized via a facile microwave-assisted hydrothermal process in Cu(CH3COO)2(0.1 M)/urea(0.5 M) and Cu(NO3)2(0.1 M)/urea(0.5 M) aqueous systems at 150 °C for 30 min. The formation processes of copper oxides were investigated, and their catalytic activities were evaluated by the epoxidation of alkenes and the oxidation of CO to CO2. Their electrochemical properties were compared as supercapacitor electrodes using cyclic voltammetry. Experimental results indicated that copper acetate solution could be hydrolyzed to form urchin-like architectured CuO, and the addition of urea accelerated this transformation. CuO nanoparticles were formed and aggregated into spheroidal form (CuO-1) in Cu(CH3COO)2/urea aqueous solution. Cu2(OH)2CO3 was formed as an intermediate, and then thermally decomposed into CuO nanorods (CuO-2) in the Cu(NO3)2/urea aqueous system. The synthesized cop...