Fabrication of multifunctional photoelectrodes by strategic placement of monofunctional heterojunction nanoparticles in the centrifuge-based thin film assembly

Abstract

The work demonstrates the ability to fabricate a multifunctional photoelectrode by the centrifugation-based deposition method using lateral and longitudinal placements of monofunctional heterojunction units. Two composite variants of gC3N4, namely FCN (Fe2O3/gC3N4) and CCN (Co2O3/gC3N4), have been prepared through the solid-state co-synthesis method. Scanning electron microscopy, transmission electron microscopy, energy dispersive x-ray spectroscopy, and x-ray diffraction analysis have been used to analyze the constitution of these composites. Stable dispersions of these materials have been prepared in propan-2-ol by ultrasonication and have been used to deposit thin films on TiO2 nanoflower array-based substrates to form various heterojunction specimens, including FCNH (Fe2O3/gC3N4/TiO2), CCNH (Co2O3/gC3N4/TiO2), and MLH (Co2O3 + Fe2O3/gC3N4/TiO2). After that photocatalytic (PC) and photoelectrochemical (PEC) measurements were carried out to ascertain the PEC activities of the fabricated heterojunction specimens, and a comparison was drawn vis-à-vis the control specimen, gC3N4/TiO2 heterojunction. PC and PEC analyses have found that the heterojunction specimen CCNH outperformed all other heterojunction specimens in terms of the generated photocurrent density. It was found that in sample MLH, the lateral placement of Fe2+ alongside Co2+ suppressed the activity of the latter. It shows the capability of the centrifugation-based technique for the easy fabrication of multifunctional photoelectrodes.