Al₂Pt for Oxygen Evolution in Water Splitting: A Strategy for Creating Multifunctionality in Electrocatalysis

Abstract

The production of hydrogen via water electrolysis is feasible only if effective and stable catalysts for the oxygen evolution reaction (OER) are available. Intermetallic compounds with well‐defined crystal and electronic structures as well as particular chemical bonding features are suggested here to act as precursors for new composite materials with attractive catalytic properties. Al2Pt combines a characteristic inorganic crystal structure (anti‐fluorite type) and a strongly polar chemical bonding with the advantage of elemental platinum in terms of stability against dissolution under OER conditions. We describe here the unforeseen performance of a surface nanocomposite architecture resulting from the self‐organized transformation of the bulk intermetallic precursor Al2Pt in OER.

Perspective on intermetallics towards efficient electrocatalytic water-splitting

“… 120 Recently, Antonyshyn et al synthesized the intermetallic Al 2 Pt phase for efficient OER giving rise to a moderate η 10 of 450 mV that was better than the Pt reference. In addition to the activity, it showed a stable performance after activation during the first 100 h for more than 450 h. 108 …”

“… 106 It is a quite simple and straightforward technique and has widely been applied to attain various noble, i.e. PtDy, 107 Al 2 Pt 108 and non-noble metal-based, i.e. Ti 2 Ni, 87 TiCo 2 , 109 Ni 2 Ta 110 intermetallic compounds for HER and OER.…”

Structural Changes of Intermetallic Catalysts under Reaction Conditions

“…[ 63 ] For example, bulk intermetallic Al 2 Pt has been used as an electrocatalyst for OER. [ 64 ] It is shown that the near‐surface region underwent restructuring during OER operation, leading to surface oxidation and the formation of platinum and aluminum oxide. The presence of surface oxides leads to the blocking of active sites as well as the reduction of electrical conductivity, accounting for the reduced activity during long‐term operation.…”

Self-standing 3D nanoporous Ag2Al with abundant surface oxygen species facilitating oxygen electroreduction for efficient hybrid Zn battery

“…In addition, the alloying effect combining Pt with the main group element Al introduces a strong covalency into the chemical bonding, and thereby increasing the chemical stability. PtAl 2 with noticeable leaching of Al and formation of intermetallic Pt showed excellent oxygen evolution performance [12]. PtAl catalysts dealloyed from Pt 8 Al 21 alloy consisting of atomic-layer-thick Pt skin and Pt-Al intermetallic compound skeletons effectively enhanced ORR performance [13].…”