Orthogonal test design for optimisation of the carbon-based nickel electrodeposits as cathode catalysts for hydrogen evolution in microbial electrolysis cell

Abstract

Nickel particles coating was electrodeposited on carbon paper (CP) surface to form carbon-based nickel, which was then used as the cathodic catalyst in MEC to evolve hydrogen production. The primary electrodeposition parameters of electrolyte concentration of nickel sulphate, imposed current density, and plating time were considered. An orthogonal test was designed based on three factors and three levels. Results showed that the optimal operating parameters were as follows: 30 g L -1 nickel sulfate, 12 A m -2 imposed current density, and 10 min of plating time. The chemical composition and morphology characteristics were revealed using XRD and SEM, respectively. In addition, the carbon-based nickel was obtained under the optimal electrodeposition parameters and used as cathode in a stably running microbial electrolysis cell. The evolved gas volume was 8.1 ± 0.1 mL, the hydrogen content was 82.6 ± 2.1%.