Layered oxyiodide CdBiO2I: An efficient visible light responsive and scalable photocatalyst

Abstract

Developing high-performance visible-light driven photocatalyst (λ ≥ 420 nm) makes significance for the efficient utilization of solar energy. Mass production and easy recycling are equally important for the practical application of powdery photocatalyst. However, it is challenging to meet the above requirements at the same time. In this work, we develop an efficient visible-light responsive layered oxyiodide CdBiO₂I nanosheets prepared by a facile direct precipitation method at ambient atmosphere, and demonstrate its upgradable features well fitting potential application. CdBiO₂I has a layered crystal structure consisting of [CdBiO₂]⁺ layer and I⁻ single layer, differing from that of BiOI composed of [BiO₂]²⁺ layer and I⁻ double layers. It displays an absorption edge of 520 nm in visible region, with a band gap of 2.52 eV CdBiO₂I has a large intrinsic effective mass difference of hole/electron, exceeding BiOI by 8-fold, which results in much higher charge separation efficiency and production of more reactive species (superoxide radicals and holes). The degradation efficiency of CdBiO₂I nanosheets for tetracycline hydrochloride reaches 84% under the visible light irradiation within 1 h, in which the degradation rate is 10 times that of BiOI. In addition, mass production (12 g catalyst at one time) and immobilization onto porous polyurethane foam of CdBiO₂I powder are also demonstrated, which indicates the scalable properties and easy recovery of the catalyst, highlighting the advantages of the current preparation method and prefiguring its potential in practical applications. This work may enlighten future research on the exploitation of solar-driven catalyst with high efficiency and strong practical applicability.