Multifunctional Salt-Assisted Construction of Lignin-Derived Ru-Co Bimetal/Carbon Composites with Rich Nanointerface for Electrocatalytic Water Splitting

Rational design of biomass-derived carbon nano-composites as bifunctional catalysts of the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) is of great significance for both the high-valued utilization of biomass waste and the practical application of water splitting. Herein, a novel multifunctional salt-assisted strategy consisting of surface/ interface engineering is proposed to achieve a lignin-derived bifunctional catalysts of OER and HER using potassium hexacyanocobaltate (PHC) as the multifunctional modifying agent and lignin as the carbon precursor. PHC can not only induce Co-based components and nitrogen doping but also dramatically improve pore structure. Profiting from the surface-interface synergistic structures of Ru-Co multiple active components and hierarchical porous carbon support with high surface area, the RuCo-NC-120 catalyst shows superior activities toward OER and HER with the overpotentials of 242 and 52 mV at 10 mA cm-2, respectively. As a consequence, the RuCo-NC-120-based alkali electrolyzer only needs a cell voltage of 1.531 and 1.825 V to achieve 10 and 200 mA cm-2, respectively, and possesses excellent long-term stability. This study provides a novel strategy to effectively regulate the composition, morphology, and pore structure of the lignin-derived carbon, and it may open new avenues for high-value utilization of lignin.

Automated summary

The rational design of biomass-derived carbon nano-composites as bifunctional catalysts for the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) is of great significance. In this study, a novel salt-assisted strategy that involves surface/interface engineering was proposed to achieve a lignin-derived bifunctional catalyst. The resulting catalyst showed superior activities towards OER and HER, and the alkali electrolyzer based on this catalyst demonstrated excellent long-term stability. This study provides a new approach for the high-value utilization of biomass waste and water splitting.