Microwave assisted green synthesis of p-type Co3O4@Mesoporous carbon spheres for simultaneous degradation of dyes and photocatalytic hydrogen evolution reaction

Abstract

Carbon spheres decorated with cobalt oxide nanoparticles, which can interact with the visible light were prepared by facile microwave assisted green chemical protocol. The combination of cobalt and carbon spheres results in the formation of p-n heterojunction. Also, this combination was effective in the separation of photogenerated electron-hole pairs. The photocatalytic property of the material was evaluated by employing it for the degradation of both anionic dye methyl orange and cationic dye malachite green in water and it is also used for the hydrogen evolution reaction. Different mass ratios such as 2, 4, 6 and 8 wt% of Co-carbon spheres were employed in the degradation process. However, Co-carbon spheres with mass ratio 6% displayed the best photocatalytic performance. The decoloration and mineralization efficiencies were 89.4% ± 2.8 and 88.6% ± 3.2 after 40 min of treatment respectively for methyl orange and malachite green. Scavenger studies further revealed the photo generated holes as the main oxidant and the synergistic effect of cobalt and carbon for excellent photocatalytic efficiency of the material.