Hydrogen production from methanol reforming electrolysis at NiO nanosheets supported Pt nanoparticles

Abstract

In this work, ultrathin NiO nanosheets (NS) supported Pt nanoparticles (NP) nanohybrids (termed as Pt-NP/NiO-NS) are synthesized by cyanogel-NaBH4 method, in-situ reduction and calcination treatment, in which the thickness of Pt-NP/NiO-NS nanohybrids is only 1.8 nm and their specific surface area is as large as 171.5 m2 g−1. The Pt-NP/NiO-NS nanohybrids can efficiently act as a versatile electrocatalyst for both methanol oxidation reaction (MOR) and hydrogen evolution reaction (HER) in alkaline environment. At Pt-NP/NiO-NS nanohybrids, only a 57 mV overpotential is required to obtain a current density of 10 mA cm−2 for HER. The MOR current at Pt-NP/NiO-NS nanohybrids can achieve 179.9 mA cm−2 at 1.45 V potential, which is 15.9 times bigger than that at NiO-NS. The excellent electrocatalytic activity and durability of Pt-NP/NiO-NS nanohybrids can be ascribed to the morphology feature of NiO-NS and synergistic effect between Pt-NP and NiO-NS. The uniformly dispersed Pt-NP at NiO-NS can serve as active sites for HER. Meanwhile, Pt-NP can modify the electronic property of NiO-NS, and boost the formation of active NiIIIOOH species. Consequently, a symmetric Pt-NP/NiO-NS||Pt-NP/NiO-NS methanol electrolyzer only requires 1.39 V electrolysis voltage for hydrogen production at cathode, accompanying with the production of value-added potassium formate at anode.