Electrodeposition of PdCu alloy and its application in methanol electro-oxidation

► We added triethanolamine (TEA) into the Pd2+ and Cu2+ mixed-ion electroplating bath to obtain a Pd-rich PdCu alloy. ► XRD analysis verified that PdCu alloys have smaller particle sizes compared with those deposited in TEA-free solutions. ► The cyclic voltammetry showed that alloys deposited with TEA have higher hydrogen desorption areas. ► Surface-modified PdCu alloys via redox replacement displayed the beneficial of Cu underpotential deposition. ► PdCu alloys fabricated with TEA and redox replacement showed better catalytic performance in the methanol electro-oxidation.