Highly-active and durable low-Pt electrocatalysts that can dramatically reduce the costly Pt usage in the oxygen reduction reaction (ORR) are urgently required for the commercialization of fuel cell vehicles. Cost-effective Pt-based intermetallic (IMC) catalysts have been regarded as the most promising alternative to boost activity and durability towards ORR, however, the formation of high-loaded Pt-based IMCs usually involves the high-temperature annealing that leads to severe agglomeration and nonuniformity of IMC nanoparticles (NPs), imposing an enormous challenge on efficient synthesis.

Motivated by such a challenge, an interdisciplinary research team led by Prof. YANG Hui and Prof. JIANG Zheng of Shanghai Advanced Research Institute reported a high-loaded (44.7 wt.%) and sub-6 nm Pt IMC catalyst, which can be controllable synthesized through a cobalt oxide aided structural-evolution strategy.  The results were published in Energy & Environmental Science recently.

The as-prepared catalyst exhibited superb electrocatalytic performance for the ORR with a greatly enhanced mass activity (MA@0.9 V) of 0.53 A mg_(Pt)^-1 and durability in model electrode measurements.

Impressively, the resultant catalyst delivered a record-high power density (2.30/1.23 Wcm^-2 for H₂-O₂/air) and extraordinary stability. Particularly, the MA@0.9 V calculated from fuel cell reaches 0.46 Amg_(Pt)^-1 in MEA configuration, exceeding the 2020 DOE target (0.44 Amg_(Pt)^-1 ) and very close to the intrinsic value, indicating that excellent activity can be highly efficient expression under PEMFC operating conditions.

The synthetic approach developed in this report provides a feasible strategy for the development of high-loaded, small-sized fuel cell electrocatalysts with high activity expression, paving a new way for future practical application of low-Pt catalysts in fuel cells.