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One of the key challenges to realize electrolysis of seawater is to develop highly active and stable electrocatalysts in oxygen evolution reaction (OER). This is crucial even for the development of electrocatalysts for hydrogen evolution reaction (HER) using three‐electrode configuration because damaged surfaces of counter electrodes (CEs), which exposed to electrochemical oxidative environments often limit the performance of cathodes in working electrodes (WEs) by lowering the electrical conductivity and poisoning the surface of electrocatalysts. Herein, we demonstrate the use of IrxTa100−xOy as a CE in simulated seawater. IrxTa100−xOy‐coated electrodes as CEs with optimized Ir:Ta ratios enable the high‐valence states of Ir for improving activity and selectivity toward the OER. Moreover, the IrxTa100−xOy CEs ensure unhindered electrochemical performance of Pt for HER in contrast to carbon‐based materials, thus highlighting their reliability as a CE. [ABSTRACT FROM AUTHOR]

Expedited conversion of O2 to H2O with minimal amounts of Pt is essential for wide applicability of PEM fuel cells (PEMFCs). Therefore, it is imperative to develop a process for catalyst management to circumvent unnecessary catalyst loss while improving the Pt utilization, catalytic activity, and durability. Here, the fabrication of a self‐standing nanofiber electrode is demonstrated by employing electrospinning. This film‐type catalyst simultaneously contains Pt–Co alloy nanoparticles and Co embedded in an N‐doped graphitized carbon (Co–Nx) support derived from the electrospun zeolitic imidazolate frameworks. Notably, the flexible electrode is directly transferrable for the membrane‐electrode assembly of high temperature PEMFC. In addition, the electrodes exhibit excellent performance, maybe owing to the synergistic interaction between the Pt–Co and Co–Nx as revealed by the computational modeling study. This method simplifies the fabrication and operation of cell device with negligible Pt loss, compared to ink‐based conventional catalyst coating methods. [ABSTRACT FROM AUTHOR]

Platinum is still the most active element for the hydrogen evolution reaction (HER); however, it suffers from its scarcity and high cost. Thus, significant efforts have been dedicated to maximize the catalytic activity with less loading. When Pt is utilized at a semiconductor surface, more factors have to be considered. Placing a catalyst directly in contact with a semiconductor supports the extraction of photogenerated minority carriers as well as boosts the catalytic reactions. In addition, a catalyst should be designed with prudence not to interfere in the light path with respect to absorption at the underlying substrate. Herein, we report the development of planar Si-based photocathodes, covered with a native oxide, for the HER, which also satisfy the prerequisites for the use of a three-dimensionally patterned, flower-like Ag–Pt catalyst. The catalyst consisted of nanoparticles of homogeneously alloyed Ag and Pt, fabricated by a galvanic exchange of Pt with Ag. Importantly, these two elements were proven to have their own functionalities. Ag not only contributed to transporting e− and Had to the Pt for subsequent processes of the HER but also effectively extracted minority carriers by diluting the high work function of Pt, leading to a better Schottky barrier at the catalyst–insulator–semiconductor junction. Furthermore, computational simulation revealed that the proposed catalyst pattern alleviated optical light loss with the increasing catalyst loading compared to the two-dimensional case. Owing to these effects, we could achieve 0.36 V (vs. reversible hydrogen electrode) as an open circuit potential and the near maximum current density of planar p-type Si. The findings in this work suggests deeper insights that could support the design of catalysts for solar-fuel systems. [ABSTRACT FROM AUTHOR]

Abstract: Filamentous bacteriophages were engineered to display 3,4‐dihydroxy‐ l‐phenylalanine (DOPA) onto which a cobalt oxide based oxygen‐evolution catalyst (Co‐OEC) spontaneously deposited at room temperature. Relative to the electrodeposited Co‐OEC, the catalyst formed on the virus exhibited improved durability and current density in a small overpotential region, as well as decreased oxidation states for the formation of Co(OH)2, as confirmed by electrochemical and X‐ray photoelectron spectroscopy analysis. Chemically deposited Co(OH)2 on the virus was oxidized to CoOOH during the water‐oxidation process. Thus, the DOPA‐displaying virus illustrates the affordability of a genetically engineered bacteriophage as a molecular support that can improve the catalytic performance of inorganic materials without any additional electrical energy. [ABSTRACT FROM AUTHOR]