Investigation and Optimization of Mxene Functionalized Mesoporous Titania Films as Efficient Photoelectrodes.

Anum Iqbal,Nasser M Hamdan

doi:10.3390/ma14216292

Abstract

Three-dimensional mesoporous TiO2 scaffolds of anatase phase possess inherent eximious optical behavior that is beneficial for photoelectrodes used for solar energy conversion applications. In this regard; substantial efforts have been devoted to maximizing the UV and/or visible light absorption efficiency; and suppressing the annihilation of photogenerated charged species; in pristine mesoporous TiO2 structures for improved solar illumination conversion efficiency. This study provides fundamental insights into the use of Mxene functionalized mesoporous TiO2 as a photoelectrode. This novel combination of Mxene functionalized TiO2 electrodes with and without TiCl4 treatment was successfully optimized to intensify the process of photon absorption; charge segregation and photocurrent; resulting in superior photoelectrode performance. The photocurrent measurements of the prepared photoelectrodes were significantly enhanced with increased contents of Mxene due to improved absorption efficiency within the visible region; as verified by UV–Vis absorption spectroscopy. The anatase phase of TiO2 was significantly augmented due to increased contents of Mxene and postdeposition heat treatments; as evidenced by structural analysis. Consequently; an appreciable coverage of well-developed grains on the FTO surface was observed in SEM images. As such; these newly fabricated conductive mesoporous TiO2 photoelectrodes are potential candidates for photoinduced energy conversion and storage applications.

Highlights

Solar radiation is the most significant source of sustainable clean energy
Due to selective etching of Al layers from the starting material in a hydrofluoric acid (HF)-assisted exfoliation process, the peaks were considerably shifted to lower angles (8.8◦, and 18.2◦) in the XRay diffraction (XRD) spectrum of the synthesized Ti3C2Tx Mxene
The broadness and suppressed intensity of the peaks in the XRD pattern of Ti3C2Tx Mxene indicated less crystallinity and perturbed structural order in the sheets, which serves as evidence of successful treatment in HF acidic solution [46]

Summary

Introduction

The practical utilization of solar radiation for the generation of clean energy has been achieved through photovoltaics and by mimicking photosynthesis through the application of photocatalysis [1]. The conversion efficacy of solar photons into charged species is mainly determined by charge separation efficiency as well as quick charge conduction toward the electrode surface, and is closely associated with the nanostructure and composition of the photoelectrode [4]. Photon absorption is strongly related to the inherent extinction coefficient and nanostructure (band gap energy), which can be modulated to utilize a wide range of the solar spectrum. An extended lifetime and smaller diffusion path for phototriggered charged species facilitate quick separation and rapid conductance of charges, effectively improving the conversion efficacy [6]

Methods

Results

Conclusion