Enhancing hydrogen production with Ni-P coated nickel foam as cathode catalyst in single chamber microbial electrolysis cells

This study employed nickel foam (Ni foam), Ni-P coated nickel foam (Ni-P) and stainless steel (SS) as cathode materials for hydrogen production in single chamber microbial electrolysis cells (MECs), to replace noble metal catalysts such as Pt. The hydrogen evolution performance of the Ni-P cathode was significantly superior to Ni foam and SS. LSV and EDS tests showed that about 8 at.% of P in the Ni-P coating exhibited the smallest hydrogen evolution overpotential. The current density and hydrogen production rate using different cathode materials in lab-scale MECs showed similar trend as the electrochemical performance of cathodes. The maximum improvement of hydrogen production rate using the Ni-P cathode was 7.5% higher than Ni foam, 110% higher than SS, while hydrogen production rate of Ni-P reached 2.29 ± 0.11 L H2/L/d at an applied voltage of 0.9 V. Owing to the improved hydrogen recovery rate, the methane generation, another challenge for the practicability of MECs, was effectively inhibited on the Ni-P cathode. This study provides useful information for the preparation of high-efficient and low-cost cathode materials in MECs.