The search for active, stable, and cost-efficient electrocatalysts for hydrogen production via water splitting could make a substantial impact on energy technologies that do not rely on fossil fuels. Here we report the synthesis of rhodium phosphide electrocatalyst with low metal loading in the form of nanocubes (NCs) dispersed in high-surface-area carbon (RhP/C) by a facile solvo-thermal approach. The RhP/C NCs exhibit remarkable performance for hydrogen evolution reaction and oxygen evolution reaction compared to Rh/C and Pt/C catalysts. The atomic structure of the RhP NCs was directly observed by annular dark-field scanning transmission electron microscopy, which revealed a phosphorus-rich outermost atomic layer. Combined experimental and computational studies suggest that surface phosphorus plays a crucial role in determining the robust catalyst properties.

Sulfur‐doped graphene (SG) is prepared by a thermal shock/quench anneal process and investigated as a unique Pt nanoparticle support (Pt/SG) for the oxygen reduction reaction (ORR). Particularly, SG is found to induce highly favorable catalyst‐support interactions, resulting in excellent half‐cell based ORR activity of 139 mA mgPt −1 at 0.9 V vs RHE, significant improvements over commercial Pt/C (121 mA mgPt −1) and Pt‐graphene (Pt/G, 101 mA mgPt −1). Pt/SG also demonstrates unprecedented stability, maintaining 87% of its electrochemically active surface area following accelerated degradation testing. Furthermore, a majority of ORR activity is maintained, providing 108 mA mgPt −1, a remarkable 171% improvement over Pt/C (39.8 mA mgPt −1) and an 89% improvement over Pt/G (57.0 mA mgPt −1). Computational simulations highlight that the interactions between Pt and graphene are enhanced significantly by sulfur doping, leading to a tethering effect that can explain the outstanding electrochemical stability. Furthermore, sulfur dopants result in a downshift of the platinum d‐band center, explaining the excellent ORR activity and rendering SG as a new and highly promising class of catalyst supports for electrochemical energy technologies such as fuel cells.

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A simple and general dealloying method is employed to fabricate nanoporous Au/Pt alloys with pre-determined alloy compositions. Structural characterization by electron microscopes demonstrates that selective etching of Cu from Au/Pt/Cu alloy precursors results in the formation of three-dimensional bicontinuous porous network structures with uniform pores and ligaments less than 10 nm. X-Ray photoelectron spectroscopy and X-ray diffraction demonstrate that nanoporous Au/Pt alloys have a single-phase cubic structure with relatively uniform compositions across the samples. These high surface area alloy nanostructures show much enhanced specific activity and distinct surface reactivity toward the electrooxidation of some small organic molecules, such as methanol and formic acid, as the Au content varies within the structure, thus holding great potential for use in clean energy and environmental applications.

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