Synthesis of Transition Metal-Based Catalysts on Nickel Foam for Enhanced Oxygen Evolution Reaction in Alkaline Water Electrolysis

Abstract

At a time when the world is urgently pursuing net zero carbon emissions, there is an urgent need to develop highly efficient energy storage options, including the production of green hydrogen by means of electrochemical water splitting. The current study sought to assess the relative merits of cost-effective electrocatalysts for the OER, paying particular attention to transition metal oxides and hydroxides with a Nickel foam support. Co(OH)2, Co3O4, NiO and Fe2O3 were synthesised by means of hydrothermal synthesis. SEM and XRD were employed to confirm the clearly defined crystalline structures and exceptional purity of the synthesised materials. Furthermore, 1M and 6M NaOH solutions were used to conduct electrochemical performance tests, confirming that the best OER activity was achieved by Co(OH)2/NF, demonstrating excellent stability over 500 cycles, whilst also recording the lowest Tafel slopes and overpotentials. Co(OH)2/NF performed best in terms of catalytic activity, recording a Tafel slope of 35 mV dec−1 and overpotentials of 401 mV at 10 mA/cm2 and 524 mV at 100 mA/cm2 in 1 M NaOH, further reduced to 353 mV at 10 mA/cm2 and 435 mV at 100 mA/cm2 in 6 M NaOH. The durability of Co(OH)2/NF was demonstrated by the fact that it remained highly stable over a total of 500 cycles. Consequently, it is possible to conclude that Co(OH)2/NF is a promising candidate for producing hydrogen via water electrolysis sustainably and efficiently.