Exotemplated copper, cobalt, iron, lanthanum and nickel oxides for catalytic oxidation of ethyl acetate

Abstract

Oxides of cobalt, copper, iron, lanthanum and nickel were prepared by an exotemplating method using two carbon materials as templates: carbon xerogel (CX) and a commercial activated carbon (AC). Samples were characterized by thermogravimetry and differential scanning calorimetry, N2 adsorption at −196°C, temperature programmed reduction, scanning electron microscopy and X-ray diffraction. All exotemplated samples showed improvements in surface area, compared with analogue commercial samples. The materials obtained were tested for ethyl acetate oxidation. CX was found to be a better templating material than AC, producing more active oxide materials. CX exotemplated NiO and Fe2O3 showed a large improvement in performance for the catalytic oxidation of ethyl acetate, compared to the commercial samples and AC analogues; nevertheless, CX exotemplated Co3O4 was the best catalyst. The commercial Co3O4 material showed also a good catalytic performance, being the most active of the commercial samples. However, some deactivation was observed with time. On the other hand, deactivation did not occur with the exotemplated material, which showed no decrease in performance up to 5 cycles and up to 72h of continuous operation (the maximum studied). The enhanced reducibility of exotemplated samples explains their better catalytic activities relatively to the commercial oxides.