Wet‐Chemical Epitaxial Growth of Metastable‐Phase Intermetallic Electrocatalysts

Abstract 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. β‐Pd 3 Bi and γ‐Pd 5 Bi 3 intermetallic NCs are epitaxially grown on the templates of face‐centered cubic Pd 3 Pb nanocubes and hexagonal close‐packed PtBi nanoplates, achieving Pd 3 Pb@Pd 3 Bi and PtBi@Pd 5 Bi 3 core–shell NCs, respectively. The obtained Pd 3 Pb@Pd 3 Bi NCs possess a mass activity and specific activity of 8.52 A mg −1 Pd 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, Pd 3 Pb@Pd 3 Bi 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.