Nickel-doped TiO2 and thiophene-naphthalenediimide copolymer based inorganic/ organic nano-heterostructure for the enhanced photoelectrochemical urea oxidation reaction

To overcome the global challenges of energy crises and environmental threats, urea oxidation is a hopeful route to utilize urea-rich wastewater as an energy source for hydrogen production. Herein, we report an inorganic/organic type of nano-heterostructure (NHseNi-TiO2/p-NDIHBT) as a photoanode with excellent urea oxidation efficiency driven by visible light. This heterostructured photoanode consists of nickel (Ni)-doped TiO2 nanorods (NRs) arrays as an inorganic part and a D-A-D type organic polymer i.e p-NDIHBT as an organic part. The as-prepared photoanode was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The morphological studies of TEM confirm the coating of p-NDIHBT on NieTiO(2) NPs (similar to 1 mm). The consequence of heterostructure formation on optical and photo-electrochemical (PEC) properties of photoanode were explored through photo-electrochemical responses under visible light irradiation. The photoelectrochemical activity of NieTiO(2) and NieTiO(2)/p-NDIHBT photoanode from linear sweep voltammetry (LSV) shows the ultrahigh photocurrent density of 0.36 mA/cm(2) and 2.21 mA/cm(2), respectively measured at 1.965 V-RHE. Electrochemical impedance spectroscopy (EIS) of both photoanodes shows a highly sensitive nature toward the urea oxidation reaction. The hybrid photoanode also exhibits high photostability, good solar-to-hydrogen conversion efficiency, and high faradaic efficiency for urea oxidation. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

To address global energy crises and environmental threats, researchers have developed an inorganic/organic nano-heterostructure as a photoanode for urea oxidation. This heterostructured photoanode demonstrates excellent urea oxidation efficiency driven by visible light. The hybrid photoanode exhibits high photostability, good solar-to-hydrogen conversion efficiency, and high faradaic efficiency for urea oxidation.