Climbing the Activity Volcano: Core–Shell Ru@Pt Electrocatalysts for Oxygen Reduction

Abstract

We outline a systematic approach to develop active catalyst materials for an electrochemical reaction. The strategy allows one to tune binding energies of oxygen reaction intermediates on a catalyst surface by taking advantage of two effects: weakening oxygen binding energies by means of thin-film overlayers, and strengthening oxygen binding energies through nanoscale effects. By engineering a core-shell nanoparticle morphology with the appropriate dimensions, that is, the thickness of the overlayer and the size of the nanoparticle, bonding properties can be modified to improve the catalytic activity of the core-shell system. We demonstrate the application of this strategy for oxygen reduction by identifying Ru@Pt as a candidate material using density functional theory calculations, and then use these calculations to guide the synthesis of active Ru@Pt core-shell catalysts. The Ru@Pt particles, synthesized using a wet chemical method, exhibit~2 times higher specific activity (based on electrochemical active surface area) than state-of-the-art Pt/C from TKK.

Facile preparation of Ag-Cu bifunctional electrocatalysts for zinc-air batteries

“…In this theory, a strategy for designing a high active catalyst for ORR was proposed. The catalyst can be prepared by synthesizing a binary or multi-alloy with various metals which have different absorption and desorption energy for oxygen [20]. Ag has the strong oxygen desorption energy, yet the Cu has forceful absorption energy.…”

Quantification of uncertainty in first-principles predicted mechanical properties of solids: Application to solid ion conductors

“…DFT calculations have been employed to identify new battery electrodes, 8 photovoltaics, 9 catalysts 10 , thermoelectrics 11 etc. An approach to computationally-guided material discovery is to employ a descriptor-based search where materials are screened for a few properties like band gap, 12 adsorption energy, 13 HOMO levels, 14 and the identified candidates are synthesized, characterized and tested for their functionality. Given the time and resource consumed for experimental testing and validation, there is a growing realization that it is crucial to quantify the uncertainty associated with the DFT-predicted property values.…”

Ag-Cu nanoalloyed film as a high-performance cathode electrocatalytic material for zinc-air battery

“…The key point for development of zinc-air battery is finding highperformance oxygen reduction reaction (ORR) catalysts. Precious metals, like Pt, are usually used as ORR catalysts [6,7]. In general, Pt-based catalysts can be prepared via various routes, such as electrochemical deposition [8], chemical vapor deposition [9,10], and facile hydrothermal method [11].…”