The oxygen evolution reaction (OER) limits the energy efficiency of electrocatalytic systems due to the high overpotential symptomatic of poor reaction kinetics; this problem worsens over time if the performance of the OER electrocatalyst diminishes during operation. Here, a novel synthesis of nanocrystalline Ni–Co–Se using ball milling at cryogenic temperature is reported. It is discovered that, by anodizing the Ni–Co–Se structure during OER, Se ions leach out of the original structure, allowing water molecules to hydrate Ni and Co defective sites, and the nanoparticles to evolve into an active Ni–Co oxyhydroxide. This transformation is observed using operando X‐ray absorption spectroscopy, with the findings confirmed using density functional theory calculations. The resulting electrocatalyst exhibits an overpotential of 279 mV at 0.5 A cm−2 and 329 mV at 1 A cm−2 and sustained performance for 500 h. This is achieved using low mass loadings (0.36 mg cm−2) of cobalt. Incorporating the electrocatalyst in an anion exchange membrane water electrolyzer yields a current density of 1 A cm−2 at 1.75 V for 95 h without decay in performance. When the electrocatalyst is integrated into a CO2‐to‐ethylene electrolyzer, a record‐setting full cell voltage of 3 V at current density 1 A cm−2 is achieved.

Amorphous Ni 79.2-x Co x Nb 12.5 Y 8.3 (x = 0, 5 at.%) alloys were synthesized using cryogenic mechanical alloying and evaluated as catalyst for the oxygen evolution reaction (OER) in alkaline media using cyclic voltammetry and Tafel measurements. Electrochemical testing showed that the amorphous alloys possessed lower Tafel values for the OER compared to crystalline Ni and Ni 95 Co 5 . Anodic cycling of amorphous Ni 74.2 Co 5 Nb 12.5 Y 8.3 resulted in a lower onset potential for the OER and decreased Tafel values while no changes were observed for amorphous Ni 79.2 Nb 12.5 Y 8.3 and crystalline Ni 95 Co 5 . Pairing of in situ confocal Raman spectroscopy with anodic cycling showed that the amorphous Ni 74.2 Co 5 Nb 12.5 Y 8.3 alloy formed reversible hydrous Co surface species instead of irreversible CoO 2 typically seen on crystalline NiCo alloys in KOH. The formation of hydrous Co surface species upon cycling was also accompanied by increased formation of β-NiOOH leading to enhanced catalytic performance of amorphous Ni 74.2 Co 5 Nb 12.5 Y 8.3 alloy over the amorphous Ni 79.2 Nb 12.5 Y 8.3 and the crystalline counterparts.

This paper describes research to understand the relationships between materials, microstructure, and performance for primary alkaline battery cathodes composed primarily of electrolytic manganese dioxide (EMD). Specifically, the effect of various carbon additives on electronic transport within cathodes was investigated. Of the various carbon additives investigated, TIMCAL BNB90 was the best performer and graphene nanopowder was the next best. These additives had the lowest Scott density and highest BET surface area of the tested additives, and exhibited well-connected and elongated carbon pathways in SEM/FIB cross sections. Additionally, this work shows a decrease in electronic conductivity for the porous cathode in the presence of KOH electrolyte. The two top-performing cathodes, when wet with concentrated KOH had a conductivity that was about 30% below that of the dry conductivity.

X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy (UPS) were performed on as-received analytical grade Co3O4 nanoparticles (<50 nm). Co3O4 has proven to be an extremely useful material for a wide variety of applications. This report provides a detailed photoelectron spectroscopy investigation of Co3O4 to aid with identification from other cobalt oxides, hydroxides, and oxyhydroxides. In addition to the survey scan, detailed charge-corrected scans for Co 2s, Co 2p, Co 3s, Co 3p, O 1s, O 2s, and C 1s surface photoelectron signals are reported. The valence states were analyzed using UPS.

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