Design and synthesis of Mo2C/MoO3 with enhanced visible-light photocatalytic performance for reduction of Cr (VI) and degradation of organic pollutants

In this study, a facile impregnation-calcination strategy was applied in order to synthesize Mo2C modified MoO3 (Mo2C/MoO3), which was then employed as catalyst for the photoreduction of Cr (VI) and photodegradation of methyl orange (MO) upon irradiation by visible light (λ > 400 nm). The apparent rate constant (k) of Mo2C/MoO3 for the MO photocatalyzed degradation reaction under visible-light irradiation was found to be 0.0171 min-1, which was 4.59 and 67.38 times higher than that of Pt/MoO3 and pristine MoO3, respectively. Study of the photocatalytic mechanism revealed that the •O2- species played a major role in MO degradation. Moreover, the addition of Mo2C enhanced the light response region of MoO3, and also promoted the photocatalytic activity of MoO3. This was due to the enhanced separation efficiency of photogenerated electron-hole pairs and broader photoresponse region. This work suggests a new use for the easily accessible Mo2C/MoO3 heterostructure and could facilitate the application of photocatalysts for wastewater treatment．