Enhanced electrocatalytic hydrogenation of levulinic acid to value-added chemical platforms†

Abstract

The electrocatalytic hydrogenation (ECH) of levulinic acid (LA) has been identified as a sustainable and energy-efficient route for the production of high-value chemicals, including γ-valerolactone (GVL) and valeric acid (VA). This study explores the electrochemical reduction of LA using electrodeposited Cu-, Ni-, and Ru-based catalysts, including their binary (CuNi, CuRu, NiRu) and ternary (CuNiRu) systems, under both acidic and alkaline conditions. Catalysts were prepared by electrodeposition from new developed formulations. Among the electrocatalysts studied, Ni-rich deposits exhibited superior performance, with CuNi and CuNiRu catalysts achieving faradaic efficiencies above 80%, LA conversion rates exceeding 85%, and GVL selectivity as high as 94% in acidic media. Electrochemical analyses revealed that the reaction pathway and product distribution were strongly influenced by catalyst composition and solution pH, with acidic conditions favouring higher conversion efficiencies and selectivity toward GVL. Conversely, alkaline media gave rise to diminished reaction rates and a shift toward VA production. In acidic medium, reusability tests assessed the long-term stability of CuNi-based catalysts, with moderate performance degradation over multiple cycles and negligible catalyst leaching. A comparative analysis with state-of-the-art electrocatalysts highlights the competitive advantages of the developed materials, particularly in terms of efficiency and selectivity. The findings emphasise the potential of electrodeposited Ni-rich deposits for scalable, cost-effective, and environmentally friendly biomass conversion, advancing the prospects of electrochemical LA valorisation as a viable alternative to conventional hydrogenation methods.