Enhanced photoelectric catalytic degradation of methylene blue via TiO 2 nanotube arrays hybridized with graphite-like carbon

Abstract

Graphite-like carbon modified TiO 2 nanotube array (TNA-G) photocatalysts were synthesized by sucrose graphitization. After the graphite-like carbon hybridization, these photocatalysts showed the enhanced photoelectric catalytic (PEC) activity under ultraviolet irradiation and the obvious PEC degradation activity under visible irradiation ( λ > 450 nm). And the optimum photoresponse was two and three times higher than that of TNA sample under ultraviolet and visible irradiation ( λ > 450 nm) after the Graphite-like carbon hybridization. The total organic carbon results suggested that TNA-G sample could mineralize methylene blue (MB) effectively. The enhancement of PEC activity originated from the synergetic effect between graphite-like carbon layer and TiO 2 nanotube array (TNA), which enhanced charge separation process remarkably. The different degradation mechanisms of MB under ultraviolet and visible ( λ > 450 nm) irradiation were suggested. MB II was dominating reactant via the PEC process and MB I was nondominant degraded via the photocatalytic process under ultraviolet irradiation; while the electric energy played a more important role under visible ( λ > 450 nm) irradiation, MB I and II were degraded at the same time without distinction.