UNLEASH: Ultralow Nanocluster Loading of Pt via Electro‐Acoustic Seasoning of Heterocatalysts

The shift toward sustainable energy has fueled the development of advanced electrocatalysts to enable green fuel production and chemical synthesis. To date, no material outperforms Pt-group catalysts for key electrocatalytic reactions, necessitating advanced catalysts that minimize use of these rare and expensive constituents (i.e., Pt) to reduce cost without sacrificing activity. Whilst a myriad of routes involving co-synthesis of Pt with other elements have been reported, the Pt is often buried within the bulk of the composite, rendering a large proportion of it inaccessible to the interfacial electrocatalytic reaction. Surface decoration of Pt on arbitrary substrates is therefore desirable to maximize catalytic activity; nevertheless, Pt electrodeposition suffers from clustering and ripening effects that result in large ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:mrow><mml:mi>⌀</mml:mi> <mml:mspace></mml:mspace> <mml:mspace></mml:mspace> <mml:mn>0.1</mml:mn> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> <mml:mspace></mml:mspace> <mml:mi>μ</mml:mi> <mml:mi>m</mml:mi></mml:mrow> <mml:annotation>$\diameter \ \!0.1-1\ \umu{\rm m}$</mml:annotation></mml:semantics> </mml:math> ) aggregates that hinder electrocatalytic activity. Herein, an unconventional synthesis method is reported that utilizes high-frequency (10 MHz) acoustic waves to electrochemically 'season' a gold working electrode with an ultralow loading of Pt nanoclusters. The UNLEASH platform is shown to facilitate high-density dispersion of nanometer-order clusters at the bimetallic interface to enable superior atomic utilization of Pt. This is exemplified by its utility for methanol oxidation reaction (MOR), wherein a mass activity of 5.28 A <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msubsup><mml:mi>mg</mml:mi> <mml:mi>Pt</mml:mi> <mml:mrow><mml:mo>-</mml:mo> <mml:mn>1</mml:mn></mml:mrow> </mml:msubsup> <mml:annotation>${\rm mg}_{\rm Pt}^{-1}$</mml:annotation></mml:semantics> </mml:math> is obtained, outperforming all other Au/Pt bimetallic electrocatalysts reported to date.