Ru/NiMnB spherical cluster pillar for highly proficient green hydrogen electrocatalyst at high current density

Abstract

Advanced OER/HER electrocatalytic alternatives are crucial for the wide adaptation of green hydrogen energy. Herein, Ru/NiMnB spherical cluster pillar (SCP), denoted as Ru/NiMnB, is synthesized using a combination of electro-deposition and hydrothermal reaction. Systematic investigation of Ru doping in the NiMnB matrix revealed significant improvements in electrocatalytic performance. The Ru/NiMnB SCPs demonstrate superior OER/HER activity with low overpotentials of 150 and 103 mV at 50 mA/cm² in 1 M KOH, making them highly competitive with state-of-the-art electrocatalysts. Remarkably, the Ru/NiMnB SCPs exhibit a low 2-E cell voltage of 2.80 V at ultra-high current density of 2,000 mA/cm² in 1 M KOH, outperforming the standard benchmark electrodes of RuO₂ || Pt/C, thereby positioning Ru/NiMnB as one of the best bifunctional electrocatalysts. These SCPs exhibit exceptional high-current characteristics, stability and corrosion resistance, as evidenced by continuous operation at 1,000 mA/cm² high-current density for over 150 h in 6 M KOH at elevated temperatures under harsh industrial conditions. Only a small amount of Ru incorporation significantly enhances the electrocatalytic performances of NiMnB, attributed to increased active sites and improved intrinsic properties such as conductivity, adsorption/desorption capability and reaction rates. Consequently, Ru/NiMnB SCPs present a promising bi-functional electrode concept for efficient green H₂ production.