Ordering Degree-Dependent Activity of Pt3M (M = Fe, Mn)Intermetallic Nanoparticles for Electrocatalytic Methanol Oxidation

Atomically ordered intermetallic alloys with uniqueelectronic and geometrical structures are highly attractive for heteroge-neous catalysis and electrocatalysis. However, the formation ofintermetallic phases generally requires high-temperature annealing toovercome the kinetic energy barrier of atom ordering, which unfortunatelycauses high material heterogeneity and thus makes it challenging toidentify the exact contribution of ordered structures to the improvedperformance. Here, we prepared a family of small-sized intermetallic core/shell Pt3M@Pt (M = Mn or Fe) catalysts with varied ordering degree by a high-temperature sulfur-confined method. We identified astrong correlation between the ordering degree of the intermetallic Pt3M core of the catalysts and their electrocatalytic activity forthe methanol oxidation reaction. Density functional theory calculations show that the intermetallic Pt3M core induces a compressivestrain on the Pt-skin, which weakens the CO*binding, lowers the free energy change from CO*to COOH*, and thereforepromotes electrocatalytic methanol oxidation.

Automated summary

Researchers have prepared a series of small-sized intermetallic core/shell catalysts with different ordering degrees using a high-temperature sulfur-confined method. They have found a strong correlation between the ordering degree of the intermetallic core and the electrocatalytic activity for the methanol oxidation reaction.