Photocatalytic reduction of mono, di, and tri-nitrophenols over a Bi2MoO6/carbon nitride heterojunction

Abstract

We employed a solvothermal and thermal pyrolysis approach to prepare a heterojunction of oxide perovskite (Bi₂MoO₆) dispersed on polymeric carbon nitride (PCN) sheets. The introduction of Bi₂MoO₆ particles onto the PCN sheets improved the light absorption characteristics of the Bi₂MoO₆/PCN heterojunction. The as synthesized Bi₂MoO₆/PCN heterojunction exhibited a larger surface area of 24 m² g⁻¹, compared to the individual Bi₂MoO₆ (18 m² g⁻¹) and PCN (7 m² g⁻¹), respectively. This enhanced surface area provided newer catalytic sites for the heterojunction. The resulting heterojunction was employed as a photocatalyst for the reduction of a series of toxic mono, di, and tri-nitrophenols, namely 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, and 2,4,6-trinitrophenol, into industrially important amino phenols. By utilizing visible light irradiation and NaBH₄ as a reducing agent, the Bi₂MoO₆/PCN photocatalyst demonstrated accelerated reduction kinetics compared to the individual catalysts. This enhanced performance was attributed to the larger surface area and suppressed charge carrier recombination of the Bi₂MoO₆/PCN heterojunction, which facilitated efficient photoreduction. Overall, this study sheds light on the promising application of oxide perovskite/PCN heterojunction systems in photocatalytic reduction reactions, offering a viable solution for mitigating emerging pollutants.