Development of octahedral shaped Zn2TiO4 loaded Ti3C2-TiO2 ternary composite with excellent photocatalytic efficiency

Abstract

The development of highly efficient and stable earth-abundant photoanode materials for photoelectrochemical water splitting is crucial for a sustainable energy economy. Being earth-abundant, 2D Ti3C2 MXene has recently emerged as a promising candidate for efficient photocatalytic performances. However, pristine Ti3C2 and its composites suffer from poor electron-hole separation and fail to prevent the spontaneous recombination process due to the poor conductivity derived from the serious agglomeration of MXene sheets during processing. Therefore, suitable heterojunction engineering of the MXene-based composites is required for their efficient photocatalytic performances. Hence, in this work, we have developed a Ti3C2-TiO2 and octahedron-shaped, nanosized Zinc titanate (Zn2TiO4) based ternary nanocomposite with optimized composition via a simple process of alkalization followed by hydrothermal. As-synthesized Ti3C2-TiO2/Zn2TiO4 (1:0.5) nanocomposite shows a 3.7-fold augmentation in photocurrent density as compared to alkali treated Ti3C2-TiO2 at a potential of 0.9 V vs Ag/AgCl resulted due to the facile charge transfer evidenced from its impedance analysis having lowest charge transfer resistance. Furthermore, the Mott-Schottky measurements reveal that the as-synthesized nanocomposites possess n-type semiconductivity and the charge carrier concentration of Ti3C2-TiO2/Zn2TiO4 (1:0.5) is almost 5.2 times higher than that of alkali-treated Ti3C2-TiO2. This work may inspire more excellent work on developing MXene-based photoanodes.