Vitamin B12 functionalized N-Doped graphene: A promising electro-catalyst for hydrogen evolution and electro-oxidative sensing of H2O2

Abstract The redox, chemical and biochemical characteristics of molecular hydrogen (H2) and hydrogen peroxide (H2O2) promise affordable, sustainable and environment-friendly solutions to some serious global challenges related to energy, environment and human health. However, the non-availability of a cheap, efficient and durable electrocatalysts continues to hamper the practical exploitation of H2 and H2O2 as solution to these challenges. Herein, we present a simple strategy for the fabrication of Vitamin B12 functionalized nitrogen-doped graphene (Vit.B12-NGr) nanohybrid, as an electrochemically stable, reusable electrocatalyst with an excellent prospect for hydrogen evolution reaction (HER) and non-enzymatic electro-oxidative sensing of H2O2. For HER, the Vit.B12-NGr nanohybrid displays onset potential of just −0.096 V vs. RHE, a low Tafel slope of ca. 60.35 mV/dec and an overpotential requirement of just −0.210 V for 10 mAcm−2. Moreover, the Vit.B12-NGr is demonstrated as a promising electrocatalytic surface for the electro-oxidative sensing of H2O2 with a sensitivity of 430 μAmM−1 (8.775 μAmM−1cm−2) and a limit of detection as low as 20 nM. These HER and H2O2 sensing parameters displayed by Vit.B12-NGr are either superior or comparable to those observed for the various recently reported state-of-the-art HER electrocatalysts and H2O2 sensors.