L-proline assisted solvothermal preparation of Cu-rich rhombic dodecahedral PtCu nanoframes as advanced electrocatalysts for oxygen reduction and hydrogen evolution reactions

Abstract

Alloying Pt with earth-abundant metal (e.g. Cu, Ni and Co) can largely improve catalytic activity of Pt-based alloyed nanocrystals by down-shifting the Pt d-band center and modulating the final size, morphology and structure. Herein, Cu-rich rhombic dodecahedral PtCu nanoframes (NFs) were obtained via a one-pot solvothermal route with l-proline and cetyltrimethylammonium chloride (CTAC) as co-structure-directing and stabilizing agents, along with OAm as the reductant. The as-prepared Pt24Cu76 NFs were identified as bifunctional catalysts for oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) in alkaline electrolyte. Specifically, the catalyst showed excellent catalytic activity and durability for ORR with positive half-wave potential at 0.95 V, outperforming that of commercial Pt/C (20 wt%, 0.88 V). Besides, it exhibited dramatically enhanced HER activity with the more positive potential at 10 mA cm−2 and smaller Tafel slope (−18 mV, 52 mV dec−1) relative to those of Pt/C (−63 mV, 69 mV dec−1). All the results demonstrate the practical applications of robust PtCu electrocatalysts in energy conversion and storage.