Sensitization of TiO2 nanoarrays by a novel palladium decorated naphthalene diimide functionalized graphene nanoribbons for enhanced photoelectrochemical water splitting

Abstract

As the heart of photoelectrochemical (PEC) cells, the photocatalyst plays a significant role in hydrogen production through PEC water splitting. In this study, the graphene nanoribbon (GNR) was used as a platform for enhancing the semiconductor properties. Naphthalene diimide (NDI) was covalently attached to the GNR surface to improve the light absorption and the charge carrier properties. Due to its unique chemical and electron structure, NDI is highly compatible with GNR and has led to increased electron transport from the photoelectrode surface to the semiconductor conduction band (TiO2). Then, to enhance the electrocatalytic activity of GNR, palladium was immobilized on the platform. The final composition was coated by drop-casting on TiO2 nanoarrays and used as a photoelectrode in a PEC cell. The electrochemical results showed the produced photocurrent density of 1.16 mA/cm2 at 1.1 V vs. RHE, and there was a significant increase compared to unmodified TiO2. The composition was characterized to examine the structures using FTIR, XRD, XPS, FESEM, and HRTEM analysis. Finally, due to the appropriate characteristics of GNR, we can hope for further studies to achieve higher efficiencies in PEC cells.