Facile synthesis of black N-TiO2 / N-RGO nanocomposite for hydrogen generation and electrochemical applications: New insights into the structure-performance relationship

Abstract

Strenuous efforts have been dedicated to obtain efficient photocatalysts with an amplified hydrogen generation employing TiO2 and reduced graphene oxide (RGO). Accordingly, black - nitrogen doped TiO2/nitrogen doped reduced graphene oxide (BNTNG) has been strategically synthesized in low temperature/pressure, vacuum annealing process using ethanol for a better photocatalyst. The pyrrolic nitrogen stabilized photocatalyst (BNTNG-2 – 2h Ultrasonication) has found to show an augmented hydrogen generation and electrochemical potency than its 1 h and 3 h counterparts (BNTNG-1 and BNTNG-3) due to the attachment of C2H4 fragments from ethanol restoring sp2 hybridization in nitrogen doped reduced graphene oxide (NRGO). Meanwhile, reduction in hydrogen production and capacitance of BNTNGs than its white analogue can be substantiated to the presence of N-O species along with oxygen vacancies / Ti3+ in BNTNG promoting electron/hole recombination centers. The recyclability of the photocatalyst is ascertained over five consecutive cycles. Plausible mechanism has been proposed for the nuances of N-O moiety and restoration of sp2 graphitic structure in BNTNG-2.

Keywords

• Black nitrogen doped TiO2/ nitrogen doped RGO
• Oxygen vacancies
• Hydrogen generation
• Supercapacitance
• C2H4 fragments
• N-O moiety