Co/Cu2O assisted growth of graphene oxide on carbon nanotubes and its water splitting activities

Abstract

A hybrid nanomaterial of Co/Cu₂O based on carbon nanotubes (CNTs) is proposed as a highly promising photocatalyst for solar hydrogen production. Cu₂O nanoparticles are active catalysts for hydrogen evolution from copper acetate by polyol process, but Cu⁰ nanoparticles are easily formed in this process, resulting in Cu associated Cu₂O. To suppress the formation of metallic copper, metallic cobalt loaded CNT is used as a substitute for the non-loaded CNT for Cu₂O formation. The metallic cobalt nanoparticles are not only effective in preventing the reduction of Cu²⁺ to Cu⁰, but they also enhance the efficiency of the CNT-substrated hybrid material preparation. Furthermore, graphene oxide (GO) is formed in the fabrication process of CNT/Co materials, and the GO is obtained from the exfoliated tube wall of CNT, which is evidenced by the uneven distribution of Co and Co/Cu₂O on the GO flakes. The hybrid materials of CNT/Co/Cu₂O and [CNT + GO]/Co/Cu₂O are investigated as photocatalysts for water splitting. The results reveal that CNT/Co/Cu₂O and [CNT + GO]/Co/Cu₂O can be used to split water, thus enabling the economic production of hydrogen.