Highly Efficient and Selective Electrocatalytic Hydrogenation of Chloronitrobenzene to Chloroaniline on Ag-Modified...

Electrocatalytic hydrogenation (ECH) for the synthesis of high-value chemicals has attracted significant research interest. Herein, we present a self-supporting Ag-modified etched Cu foam electrode (Ag-eCF) fabricated via a facile chemical etching and subsequent auto-reduction of Ag+, which achieved exceptional performance with an activity of 2.38 μmol h-1 cm-2, 95.37% selectivity of p-ClPhNH2, and a Faradaic efficiency of 98.9% at a current density of 50 mA cm-2, along with excellent reusability and broad substrate applicability. Structural and electrochemical characterizations reveal that Cu and Ag serve as the active sites for the selective hydrogenation of the nitro groups in ClPhNO2s, while surface etching of CF increases the electrochemically active surface area and reduces charge-transfer resistance. The incorporation of Ag optimizes the adsorption/desorption behavior of the reactant and target product, promoting the generation of active hydrogen. Density functional theory (DFT) calculations further confirm that the enhanced performance originates from strengthened p-ClPhNO2 adsorption and a lowered reaction energy barrier after Ag modification. Moreover, higher current density, polar solvents, and elevated reactant concentrations favor the ECH of p-ClPhNO2 to p-ClPhNH2 over the 0.2 wt% Ag-eCF catalyst. This work offers a rational design strategy for fabricating high-performance electrodes for the production of value-added chemicals.