Temperature‐Tuned Electrocatalytic Valorization of Levulinic Acid to γ‐Valerolactone or 4‐Hydroxyvaleric Acid over CuNi(Ru)/Graphene Nanowalls

Temperature‐modulated electrocatalytic hydrogenation of levulinic acid (LA) to γ‐valerolactone (GVL) or 4‐hydroxyvaleric acid (HVA) was investigated over CuNi and CuNiRu catalysts electrodeposited onto vertically aligned graphene nanowalls. Systematic potential (–1.6 to –2.0 V vs. Ag|AgCl) and temperature (5°C–50°C) studies revealed a clear product switch: at 5°C all catalysts showed > 95% selectivity to HVA, whereas at 50°C GVL dominated. Among the compositional configurations, trimetallic CuNiRu (50 mC cm −2 ) achieved the highest performance, affording 96.6% LA conversion, 92.4% GVL yield, and 98.5% selectivity at 50°C with minimal Ru loading. The synergy between Ru sites (promoting hydrogen activation and lactonization) and the high‐roughness nanowall scaffold suppressed H 2 evolution, minimized metal leaching (<1%), and delivered stable operation under ambient pressure. The system maintained performance over multiple cycles and preserved selectivity even under concentrated LA solutions, confirming architectural robustness. Faradaic efficiencies up to 89%, low energy consumption (~0.12 kWh mol −1 ), and energy storage efficiencies > 70% underscore the viability of this system for direct electricity‐to‐fuel conversion. These temperature–potential insights establish a tuneable platform where low‐temperature operation yields HVA, whereas moderate temperatures (50°C) enable near‐quantitative GVL production.