Decoration of CdS nanoparticles on dense and multi-edge sodium titanate nanorods to form a highly efficient and stable photoanode with great enhancement in PEC performance

Abstract

This study provided the preparation and application of a highly efficient photoanode having dense and efficient sodium titanate (NTO) nanorods decorated with CdS nanoparticles. The (NTO) nanorods were grown densely on the surface of Ti foil by a one-step hydrothermal method, which provides many step edges on the surface of the nanorods and a direct pathway for transfer of photogenerated electrons to the Ti substrate to improve the water splitting ability. The CdS nanoparticles were deposited on the surface of NTO nanorods using a simple and low-cost successive ionic layer adsorption and reaction (SILAR) method to greatly enhance the absorption of visible light. Rough surfaces of the as-synthesized nanorods were favorable sites for growing the CdS nanoparticles, which formed a tremendous connection and heterojunction at the interface between NTO and CdS. This efficient connection caused a noticeable enhancement in photocurrent density with great stability in integrated NTO/CdS photoanodes, due to the efficient separation and transfer of charge carriers. The NTO/CdS12 electrode with optimum SILAR cycles showed the highest photocurrent density around 2.37 mA cm⁻² at 1 V vs. RHE, which was 36 times higher than that of pure NTO (around 0.066 mA cm⁻²), and interestingly, this electrode retained more than 95% of its initial photocurrent density, even after 6000 seconds.