Electrocatalytic Hydrogenation of Lignin-Derived Phenol into Alkanes by Using Platinum Supported on Graphite

In this work, electrocatalytic hydrogenation (ECH) of phenol to cyclohexane and cyclohexanol was studied. Experiments were run in a H-type cell with a Pt sheet as anode. The cathode material and structure were found to have a large effect on the ECH of phenol. Among the cathodes studied, the 1.5% Pt supported on graphite gave the highest product yield and current efficiency. Temperature was another important variable, the yield of cyclohexane increased from 44.1% at 20°C to 63.7% at 60°C, but then dropped back to 50.3% at 80°C. Effects of electrolyte composition on ECH of phenol were also investigated. The yield of cyclohexane was highest when 0.2 mol/L HClO4 as electrolyte. Variable current studies in the range of 10–90 mA showed an increase in product yields with increasing current from 10–30 mA, but yields decreased when current above 70 mA. The suitable starting concentration of phenol was 50 mmol/L.