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

• Published in: International journal of hydrogen energy 2023-03, Vol.48 (20), p.7361-7373
• Main Authors: Bezboruah, Jasmine, Sanke, Devendra Mayurdhwaj, Munde, Ajay Vinayakrao, Das, Sarasija, Karmakar, Himadri Shekhar, Zade, Sanjio S.
• Format: Article
• Language: English
• Subjects: Energy; Environmental; Inorganic/organic nano-heterostructures; Ni-doped TiO2; Photoelectrochemical urea oxidation
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2022.11.098

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 (NHs–Ni-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 Ni–TiO2 NPs (∼1 μm). The consequence of heterostructure formation on optical and photoelectrochemical (PEC) properties of photoanode were explored through photoelectrochemical responses under visible light irradiation. The photoelectrochemical activity of Ni–TiO2 and Ni–TiO2/p-NDIHBT photoanode from linear sweep voltammetry (LSV) shows the ultrahigh photocurrent density of 0.36 mA/cm2 and 2.21 mA/cm2, respectively measured at 1.965 VRHE. 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. [Display omitted] •Novel Ni-doped TiO2-based inorganic/organic materials are introduced for PEC urea oxidation.•Synthesis of Ni-doped rutile TiO2 nanorods (NRs).•Electropolymerization of synthesized naphthalene diimide-based doner-acceptor-doner type small molecule.•Ni–TiO2/p-NDIHBT exhibits strong photocurrent, high stability, and enhanced UOR performance.•Formation of Ni–TiO2/p-NDIHBT nano-heterojunction can enhance photoexcited electrons (e−) and holes (h+).