Alkali-assisted synthesis of direct Z-scheme based Bi2O3/Bi2MoO6 photocatalyst for highly efficient photocatalytic degradation of phenol and hydrogen evolution reaction

Abstract

Semiconductor based photocatalytic technology has attracted substantial research attention based on its potential to overcome environmental and energy crisis. The conventional photocatalysts with their issues such as rapid charge recombination are considered unfavorable candidates for practical applications. Herein, a novel direct Z-scheme based photocatalyst composed of Bi2O3/Bi2MoO6 hetrojunction is proposed for efficient photo-degradation of phenol and hydrogen (H2) production reaction. The hetrojunction comprises of ultra-thin (2D) Bi2O3 nanosheets, in-situ grown over 3D Bi2MoO6 microspheres via simple alkali treatment of Bi2MoO6 succeeded by air calcination step. The relative mass ratio of Bi2O3 and Bi2MoO6 could be fine-tuned by controlling the alkali dosage (i.e. NaOH or KOH). Unlike the conventional Bi2O3/Bi2MoO6 hetrojunction, the proposed catalyst follow a direct Z-scheme charge transfer mechanism which permits superior photocatalytic activity with 96.4% phenol degradation efficiency and high hydrogen evolution rate of 52 μmol·g−1 under visible light irradiation. The exuberant performance is accredited to the spatially separated redox charge carriers, excellent light harvesting capability and fast-charge transportation characteristics of the proposed photocatalyst. The present work serves as a primary pathway to design and develop efficient Bi2MoO6-based direct Z-scheme photocatalysts with promising applications in environmental remediation and solar fuel production.