Synthesis of a semi-conductor-like MOF with black phosphorous as a composite for visible light-driven photocatalysis

Abstract

The fabrication of nanocomposites of a metal-organic framework with two-dimensional materials for photocatalytic water splitting and environmental remediation has been the focus of the scientific community for many years now. In the work reported here, MIL-125 (Ti) was functionalized using few-layer black phosphorus (FLBP) via a two-step hydrothermal and sonication approach. The as-synthesized composite materials were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) and photoluminescence (PL) spectroscopy. The techniques revealed that the nanocomposites exhibited circular blocks and a sheet-like morphology; they also showed enhanced visible light absorption and thus could be applied in visible-light-driven photocatalytic water treatment or water splitting. Electrochemical impedance spectroscopy (EIS) showed that the composite referred to as 4%BpMIL displayed the lowest recombination of all the composites (MIL-125(Ti) > 12%BpMIL> 6%BpMIL > 4%BpMIL > FLBP) with high effectual charge transfer between FLBP and MIL-125(Ti) via a p-n junction.