Construction of high-proportion ternary dual Z-scheme Co3O4/NiCo2O4/NiO photocatalytic system via incomplete solid phase chemical reactions of Co(OH)2 and Ni(OH)2 for organic pollutant degradation with simultaneous hydrogen production

Abstract

Z-scheme photocatalysts can be prepared through combining two suitable photocatalyst monomers, but the contact interfaces between two nanoparticles are generally formed. The lattice mismatches and defects are often present on the contact interface, which is not conducive to the photo-induced electron transfer. Consequently, in this work, a novel high-proportion ternary dual Z-scheme Co3O4/NiCo2O4/NiO photocatalyst is prepared via incomplete solid phase chemical reactions of Co(OH)2 and Ni(OH)2. In this way, the formed perfect interfaces between Co3O4 and NiCo2O4 and between NiCo2O4 and NiO may significantly facilitate the photo-induced electron transfer. For estimating the activity of the prepared samples, the experiments of photocatalytic degradation of methylene blue (MB) with simultaneous hydrogen production are carried out. The influences of Ni(OH)2 and Co(OH)2 M proportion, calcination temperature and calcination time on the activity of the prepared samples are researched. Besides, the stability and recycling capacity of the Co3O4/NiCo2O4/NiO photocatalyst are assessed by four cycle experiments. A mechanism on MB photocatalytic degradation with simultaneous hydrogen production caused by high-proportion ternary dual Z-scheme Co3O4/NiCo2O4/NiO photocatalyst is proposed. It is hoped that this work can provide some valuable ideas on preparation of new-style photocatalysts for efficient photocatalytic degradation of organic pollutants with synchronous hydrogen production.