“Breaking the O═O Bond”: Deciphering the Role of Each Element in Highly Durable CoPd₂Se₂ toward Oxygen Reduction Reaction

Abstract

In-depth insight into oxygen reduction reaction (ORR) electrocatalyst with high figures of merit (activity, stability, and selectivity) is highly crucial to rationally design electrocatalyst with a potential to replace state-of-the-art Pt/C. This work reports the synthesis of CoPd 2 Se 2 nanoparticles that show remarkably high stability of 50000 electrochemical cycles toward ORR. Morphology of the particles is characterized using SEM and TEM microscopy techniques and simulated using Bravais−Friedel−Donay−Harker (BFDH) morphology calculation method. A deconvoluted approach was used to understand the role of each element in the compound. DFT calculation was performed to have an in-depth analysis of the active site. Co and Pd provided an active site for the O 2 adsorption and Pd dissociates the OO bond. The back-donation of substantial electron density to the π* antibonding orbital of the molecule expedites the 4e-reduction of O 2 throughout the entire potential range. During the electrochemical stability test, Se forms a protective layer and prevents the active Co and Pd sites from OH poisoning.

Se Atom Doping Enhances the Catalytic Activity of Co@NC for Oxygen Reduction Reaction

“…Specifically, the micropore structure in the catalyst can host more active sites, the mesopores play a key role in promoting electrolyte wetting in the micropores and the formation of the electrode/electrolyte interface, and the lack of a macroporous structure significantly increases the mass transfer resistance of the oxygen reduction process. [34] Therefore, the optimized pore structure using SeO 2 pyrolysis can effectively shorten the proton and ion transport paths [35] and promote the mass transfer of the oxidative progenitor process, thus allowing the active site to fully contact the electrolyte, and this optimized pore structure makes Co-Se@NC-1000 have very excellent ORR performance under both acidic and alkaline conditions.…”

ZIF‐derived Low‐Cu‐loaded Carbon Catalysts for Oxygen Reduction Reaction

“…The ink was dropped on the RRDE with total catalyst loading of almost 400 μg cm À 2 . All the measured potentials were converted to the reversible hydrogen electrode (RHE) by equation (3). Prior to the electro-catalytic measurements, the electrolyte was purged with O 2 (99.9 %) for at least 30 min to confirm that the test is in an O 2 -saturated environment.…”

“…[1] The keys to converting chemical energy into electrical energy are that the oxidation reaction at the anode and the oxygen reduction reaction (ORR) at the cathode. [2] Due to the strong O=O bond (498 kJ mol À 1 ), [3] the kinetics of oxygen reduction is slow, which results in a larger overpotential and even requiring nearly ten times the catalyst loading for the cathode than that of anode. [4] Currently, Pt-group metals are commonly used to break the activation barriers.…”

Enhanced Electrocatalytic Activities of In Situ Produced Pd/S/N-Doped Carbon in Oxygen Reduction and Hydrogen Evolution Reactions

“…Precise tuning of the electronic properties of palladium to augment its catalytic activity has been explored. − The benefits of nanotechnology have made great strides to manipulate the electronic structure of catalytical materials through nanoengineering (size, shape, alloying, and porous structure). − One of the examples is significant progress in the field of nanoporous metals designed through electrochemical deposition approaches using hard templates and soft templating techniques . In addition to these engineering approaches, catalytical materials supported by the substrate also have great importance to tune the catalytical activity through interfacial interactions .…”