A TiO2 nanorod and perylene diimide based inorganic/organic nanoheterostructure photoanode for photoelectrochemical urea oxidation

Abstract

Visible light-driven photoelectrochemical (PEC) urea oxidation using inorganic/organic nano-heterostructure (NH) photoanodes is an attractive method for hydrogen (H₂) production. In this article, inorganic/organic NHs (TiO₂/PDIEH) consisting of a N,N-bis(2-ethylhexyl)perylene-3,4,9,10-tetracarboxylic diimide (PDIEH) thin layer over TiO₂ nanorods (NRs) were fabricated for the PEC urea oxidation reaction (UOR). In these NHs, a PDIEH layer was anchored on TiO₂ NR arrays using the spin-coating technique, which is beneficial for the uniform deposition of PDIEH on TiO₂ NRs. Uniform deposition facilitated adequate interface contact between PDIEH and TiO₂ NRs. TiO₂/PDIEH NHs achieved a high current density of 1.1 mA cm⁻² at 1.96 V_RHE compared to TiO₂ NRs. TiO₂/PDIEH offers long-term stability under light illumination with 90.21% faradaic efficiency. TiO₂/PDIEH exhibits a solar-to-hydrogen efficiency of 0.52%. This outcome opens up new opportunities for inorganic/organic NHs for high-performance PEC urea oxidation.