One-step hydrothermal treatment to fabricate Bi2WO6-reduced graphene oxide nanocomposites for enhanced visible light photoelectrochemical performance

Abstract

Considering that ultraviolet light may cause the denaturation of biomaterials, searching for and engineering innovative and advanced nanomaterials with excellent photoelectrochemical properties under visible light illumination are of great significance in the fundamental understanding and application of photoelectrochemical (PEC) sensors. As a widely applied visible light response material, the applications of Bi₂WO₆ in PEC fields were restricted because of the rapid recombination of photoinduced electron–hole pairs. In this work, Bi₂WO₆ functionalized reduced oxide (Bi₂WO₆–rGO) nanocomposites (NCs) were prepared by a one-step solvothermal method. After optimizing the content of rGO, the Bi₂WO₆–rGO_2.94% NCs displayed enhanced photocurrent intensity (the starting mass ratios of GO to Bi₂WO₆ = 0.0294), which was nearly 2.7-fold compared to that of pure Bi₂WO₆ nanoparticles because of the separation of the photoinduced carriers and the enhancement of visible light absorption. Based on the coupling of Pb²⁺-induced allosteric transition of G-quadruplex DNAzyme and the enzymatic biocatalytic precipitation (BCP), Bi₂WO₆–rGO_2.94% NCs were applied in the construction of a novel PEC sensor for the determination of Pb²⁺. The as-fabricated PEC sensor exhibited good anti-interference ability and a good linear relationship was obtained between the photocurrent intensity and the logarithm of the Pb²⁺ concentration over a concentration range from 0.01 to 50 μM and with a detection limit of 3.3 nM (S/N = 3), indicating that Bi₂WO₆–rGO NCs would be promising materials for PEC sensing.