Ultrathin SnS2 Nanosheet Decorated B-TiO2 / TiO2 Core Shell Nanorods for Photoelectrochemical Water Splitting

Abstract

Morphology tailoring and heterostructure designing has emerged as one of the most significant frontrunners in research on photoelectrochemical water splitting. In this work we demonstrate the synthesis of core shell Black TiO2 @ TiO2 nanorods by a one step electrochemical treatment using NaBH4 to partially reduce surface Ti4+ ions to Ti3+ by chronoamperometry in order to generate a core shell structure. The effect of anodic potential for the electrochemical reduction process was studied. The fabricated electrodes were further decorated with SnS2 nanosheets by a facile solvothermal method to generate a ternary SnS2 / B-TiO2 @ TiO2 heterojunction. The photoelectrochemical performance of the fabricated photoanodes were analyzed using A.M 1.5 G solar simulator with a anodic potential sweep from -0.5 V to 2 V. A maximum ABPE % of 1.12 % was observed at 0.61 V using Na2S / Na2SO3 as an electrolyte. DFT calculations were carried out to understand the underlying electronic structure of the heterostructure and charge transfer pathways. Morphological analysis was carried out using characterization techniques like XRD and SEM. Optical analysis was carried out using UV-Vis spectra and PL measurements. Charge transfer kinetics were analyzed using EIS and Mott-Schottky plots. This work hopes to inspire further research in the designing of ternary heterostructures by electrochemical surface treatment of semiconductor nanostructures.