Electrocatalytic activity of bimetallic PdAu nanostructure supported on nanoporous stainless steel surface using galvanic replacement reaction toward the glycerol oxidation in alkaline media

Co-deposition of Au and Pd through galvanic replacement reaction (GRR) was used as a highly efficient method to fabricate bimetallic PdAu nanostructure on a nanoporous stainless steel substrate (Pd-Au/NPSS). Then, the electrocatalytic behavior of Pd-Au/NPSS for glycerol oxidation was studied in alkaline media and compared with Au/NPSS and Pd/NPSS using electrochemical methods. FESEM images showed that a sponge-like overlayer containing many nanosheets and pores covered the Pd-Au/NPSS surface. X-ray and electrochemical analysis also indicated that the Pd-Au/NPSS surface was composed of two parts of a non-alloyed gold and a solid solution of PdAu alloy. For glycerol oxidation, the PdAu nanostructure exhibited higher current density and mass activity (more than 2 times) than Pd/NPSS and Au/NPSS. The onset potential for Pd-Au/NPSS was 0.08 V lower than that for Au/NPSS and only 0.01 V higher than that for Pd/NPSS. The way employed for the Pd-Au/NPSS fabrication reduced effectively the Pd loading (11 μg.cm−2) and meantime, enhanced catalytic performance. The effects of Pd:Au precursors molar ratio and GRR time were also investigated. It was found that the appropriate amount of non-alloyed gold improved the catalytic activity. Also, Pd-Au/NPSS showed high tolerance against the poisoning species. Accordingly, Pd-Au/NPSS could be employed as an efficient anode for use in alkaline fuel cells. Moreover, co-deposition of noble metals through GRR could be developed as a simple, facile, green and controllable method to fabricate other bimetallic noble metal nanostructures with high utilization efficiency.