This study reports the preparation, characterization, and electrocatalytic properties of palladium-based catalysts containing ceria (CeO 2 ) on carbon black (CB) and onion-like carbon (OLC) supports. The electrocatalysts (Pd− CeO 2 /CB and Pd−CeO 2 /OLC) exhibit a large specific surface area, pore volume, and small particle size, as well as enhanced interfacial interaction and synergy among Pd, CeO 2 , and OLC in Pd−CeO 2 /OLC that are valuable for improved electrocatalysis. The presence of CeO 2 in Pd−CeO 2 /OLC induces ca. 7% defects and modifies the electronic structure of the Pd/OLC interface, significantly improving the electrical conductivity due to enhanced charge redistribution, corroborated by density functional theory (DFT) calculations. Pd−CeO 2 /OLC displays the lowest adsorption energies (H*, OH*, and OOH*) among the series. For the hydrogen oxidation reaction (HOR), Pd−CeO 2 /OLC delivers significantly enhanced HOR (mass-specific) activities of 4.2 (8.1), 13.2 (29.6), and 15 (78.5) times more than Pd−CeO 2 /CB, Pd/OLC, and Pd/CB, respectively, with the best diffusion coefficient (D) and heterogeneous rate constant (k). Pd−CeO 2 /OLC also displays less degradation during accelerated durability testing. In an anion-exchange-membrane fuel cell (AEMFC) with H 2 fuel, Pd−CeO 2 /OLC achieved the highest peak power density of 1.0 W cm −2 at 3.0 A cm −2 as compared to Pd−CeO 2 /CB (0.9 W cm −2 at 2.2 A cm −2 ), Pd/OLC (0.6 W cm −2 at 1.7 A cm −2 ), and Pd/CB (0.05 W cm −2 at 0.1 A cm −2 ). These results indicate that Pd−CeO 2 /OLC promises to serve as a high-performing and durable anode material for AEMFCs.

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Porous ternary Pd-based catalysts are highly promising for various electrocatalytic applications, due to their low-Pd mass, high surface area, accessible active sites, and tunable electronic structure, however, their activity for...

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Rechargeable zinc-air batteries (RZABs) are one of the most promising next-generation energy-storage technologies for stationary applications (home and industry), wearable and portable electronics, and transportation (including electric vehicles) due to their high energy density, environmental friendliness, safety, and low cost. However, RZABs still face serious challenges (such as sluggish oxygen reactions, poor durability, inferior reversibility of the zinc anode, and low cell energy efficiency) that conspire against their widespread commercialization. The reactions that occur at the three key components of the RZAB (air cathode, zinc anode, and electrolyte) cooperatively conspire against its performance. Thus, this review focuses on the bifunctional electrocatalytic events at the cathode (i. e., oxygen reduction reaction (ORR) and oxygen evolution reaction (OER)). That is in addition to the recent developments aimed at mitigating the performance-limiting events at the anode and the electrolytes. This review directs the attention of researchers and users to the critical areas for the development of the next-generation RZABs.