Publications by authors named "Lee Casalena"

Accelerating the alkaline hydrogen evolution reaction (HER), which involves the slow cleavage of HO-H bonds and the adsorption/desorption of hydrogen (H*) and hydroxyl (OH*) intermediates, requires developing catalysts with optimal binding strengths for these intermediates. Here, the unconventional hexagonal close-packed (HCP) high-entropy alloy (HEA) atomic layers are prepared composed of five platinum-group metals to enhance the alkaline HER synergistically. The breakthrough is made by layer-by-layer heteroepitaxial deposition of subnanometer RuRhPdPtIr HEA layers on the HCP Ru seeds, despite the thermodynamic stability of Rh, Pd, Pt, and Ir in a face-centered cubic (FCC) structure except for Ru.

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Using scanning transmission electron microscopy, along with electron energy loss spectroscopy, under cryogenic conditions, we demonstrate transition-metal dissolution from a layered Ni-rich oxide cathode material and subsequent diffusion into the bulk of a lithium thiophosphate solid electrolyte during electrochemical cycling. This problem has previously only been considered for liquid-electrolyte-based batteries.

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Catalytic CO reduction to fuels and chemicals is a major pursuit in reducing greenhouse gas emissions. One approach utilizes the reverse water-gas shift reaction, followed by Fischer-Tropsch synthesis, and iron is a well-known candidate for this process. Some attempts have been made to modify and improve its reactivity, but resulted in limited success.

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