Robust PtRu catalyst regulated via cyclic electrodeposition for electrochemical production of cyclohexanol

Electrocatalytic hydrogenation (ECH) of phenol has been recognized as a promising route towards facile and green production of cyclohexanol. However, the practical application is hindered by product selectivity and catalyst durability. Herein, a series of PtRu electrocatalysts composed of metallic Pt0 and RuO2 species are in situ fabricated on carbon paper via cyclic electrodeposition, showing outstanding activity and stability for ECH of phenol. At ambient temperature and a current density of 10 mA cm−2, the optimal Pt3Ru3 catalyst achieves a 100 % selectivity to cyclohexanol at a 100 % conversion of phenol in 0.1 M H2SO4. At 100 mA cm−2, Pt3Ru3 achieves an outstanding faradaic efficiency of ∼87 % and a cyclohexanol production of 52.6 mg cm−2h−1. Two parallel ECH pathways from phenol to cyclohexanol are identified. In situ Raman spectroscopy and kinetic study reveal that phenol could be hydrogenated over Pt3Ru3 in acidic electrolyte via proton-coupled electron transfer with the destruction of conjugated π bond of aromatic ring. This work offers an effective approach for facile construction of durable electrode material and an efficient electrochemical strategy for phenol hydrogenation.