Wet-Chemical Epitaxial Growth of Metastable-Phase Intermetallic Electrocatalysts

Metastable-phase intermetallic compounds (IMCs) provide great flexibility to modify the electronic structure and surface coordination environment of metallic catalysts for various reactions. However, the synthesis of metastable-phase IMCs with high catalytic performance remains a great challenge due to their thermodynamically unstable nature. Here, a wet-chemical epitaxial growth strategy to synthesize metastable-phase Pd-Bi intermetallic nanocrystals (NCs) is reported. beta-Pd3Bi and gamma-Pd5Bi3 intermetallic NCs are epitaxially grown on the templates of face-centered cubic Pd3Pb nanocubes and hexagonal close-packed PtBi nanoplates, achieving Pd3Pb@Pd3Bi and PtBi@Pd5Bi3 core-shell NCs, respectively. The obtained Pd3Pb@Pd3Bi NCs possess a mass activity and specific activity of 8.52 A mg-1Pd and 11.59 mA cm-2 for ethanol oxidation reaction, which is 7.5 and 3.6 times as high as those of commercial Pd/C, respectively. Meanwhile, Pd3Pb@Pd3Bi NCs possess superior stability than commercial Pd/C. This work advances the design and synthesis of high-performance metastable-phase IMCs, opening an avenue for electrocatalytic ethanol oxidation and beyond. The metastable beta-Pd3Bi and gamma-Pd5Bi3 intermetallic NCs are epitaxially grown on the templates of face-centered cubic Pd3Pb nanocubes and hexagonal close-packed PtBi nanoplates, achieving Pd3Pb@Pd3Bi and PtBi@Pd5Bi3 core-shell NCs. The obtained Pd3Pb@Pd3Bi NCs exhibit outstanding electrocatalytic activity and stability toward ethanol oxidation reaction in alkaline media. image