Nanostructured BiOI–GO composite: facile room temperature synthesis with enhanced multifunctionality in field emission and photocatalytic activity

Abstract

Coupling of layered semiconductors with graphene-based materials could enable enhanced performance as compared to the pristine counterparts. Herein, we report enhanced multifunctional behaviour of a bismuth oxyiodide–graphene oxide (BiOI–GO) composite regarding its field emission and photocatalytic characteristics. The layered bismuth oxyiodide (BiOI) nanodiscs and nanostructured BiOI–GO composite were synthesized at room temperature employing a facile, single step precipitation method. The as-synthesized products were characterized using XRD, SEM, TEM, and a Raman spectrophotometer so as to reveal their phase, morphological and structural properties. Field emission (FE) studies of pristine layered BiOI nanodiscs and BiOI–GO nanocomposite emitters were carried out at the base pressure of ∼1 × 10⁻⁸ mbar. The values of turn on field required to draw an emission current density of 10 μA cm⁻² are found to be 2.7 and 1.2 V μm⁻¹ for BiOI nanodiscs and BiOI–GO nanocomposite emitters, respectively. Extraction of an emission current density of ∼1150 μA cm⁻² from the BiOI–GO nanocomposite emitter at the remarkably low applied field of 2.8 V μm⁻¹ signifies its enhanced FE performance. The superior FE characteristics of the BiOI–GO nanocomposite emitter are attributed to modulation of the electronic properties due to composite formation, and the high aspect ratio of the nanosheets/nanodiscs. Furthermore, the BiOI–GO nanocomposite exhibits enhanced photocatalytic activity towards degradation of methyl orange (MO) dye.