A Facile and Environmentally Friendly One-Pot Synthesis of Pt Surface-Enriched Pt-Pd(x)/C Catalyst for Oxygen Reduction

Rechargeable Zinc-Air Battery with Ultrahigh Power Density Based on Uniform N, Co Codoped Carbon Nanospheres

Highly efficient catalysts for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are key to the commercialization of rechargeable zinc-air batteries (ZABs). In this work, a catalyst with uniform nanospherical morphology was prepared from cobalt nitrate, acetylacetone, and hydrazine hydrate. The final catalyst possesses high ORR and OER performances, with a half-wave potential of 0.911 V [vs reversible hydrogen electrode (RHE)] for ORR and a low potential of 1.57 V (vs RHE) at 10 mA cm^-2 for OER in 0.1 M KOH solution. Specially, a ZAB based on the catalyst demonstrates an ultrahigh power density of 479.1 mW cm^-2, as well as excellent stability, and potential in practical applications.

Designing Robust Support for Pt Alloy Nanoframes with Durable Oxygen Reduction Reaction Activity

Polymer electrolyte membrane fuel cells are appealing to resolve the environmental and energy issues but are still heavily inhibited by the dilemma of fabricating effective and durable electrocatalysts for oxygen reduction reaction (ORR). In this work, highly open Pt₃Cu nanoframes and one-dimensional, hollow titanium nitride architectures are both successfully explored and implemented as the new system to replace the traditional Pt-carbon motif. The ORR performance of the obtained electrocatalyst shows specific and mass activities of 5.32 mA cm^-2 and 2.43 A mg_Pt^-1, respectively, which are 14.4 and 11.6 times higher than those of the commercial Pt/C. Notably, the novel catalyst also exhibits high stability and a much slower performance degradation than that of the benchmarked Pt₃Cu/C with the same durability testing procedures. The comprehensive data confirm that the new type of catalyst possesses a high charge transfer during the ORR process, and the unique structure and synergistic effects between anchored Pt and the support mainly contributes to the high stability. This work provides a strategic method for designing an effective ORR electrocatalyst with desirable stability.