Electrocatalytic Hydrogenation of Oxygenated Compounds in Aqueous Phase

Abstract

Electrocatalytic hydrogenation is a strategy to hydrogenate biogenic compounds under ambient conditions by replacing the thermal and H2 inputs by cathodic potential. This work compares the performances of this approach (in aqueous phase at room temperature) for the conversion of a variety of model oxygenated compounds over a series of metals. The target functionalities were carbonyl groups, aromatic rings, and ether bonds. All of the metals explored (Pt, Rh, Pd, and Cu) are active for the reduction of carbonyl compounds to alcohols. The conversion rate of benzaldehyde increased as a function of the metal as Pt < Rh < Pd (Cu was tested under different conditions). In contrast, only Rh and Pt were active for hydrogenation of aromatic rings (Rh was more active than Pt). In a comparison of the target functionalities, carbonyl groups are more reactive than aromatic rings and ether bonds in phenolic compounds and diaryl ethers on all of the explored metals. This carbonyl reactivity, however, is enhanced by the ...