Developing an efficient electrocatalyst for the hydrogen evolution reaction (HER) working in both acidic and alkaline solutions is highly desirable, but still remains challenging. Here, PtxNi ultrathin nanowires (NWs) with tunable compositions (x = 1.42, 3.21, 5.67) are in situ grown on MXenes (Ti3C2 nanosheets), serving as electrocatalysts toward HER. Such PtxNi@Ti3C2 electrocatalysts exhibit excellent HER performance in both acidic and alkaline solutions, with the Pt3.21Ni@Ti3C2 being the best one. Specifically, Pt3.21Ni@Ti3C2 achieves record‐breaking performance in terms of lowest overpotential (18.55 mV) and smallest Tafel slope (13.37 mV dec−1) for HER in acidic media to date. Theory calculations and X‐ray photoelectron spectroscopy analyses demonstrate that the coupling of MXenes with the NWs not only approaches the Gibbs free energy for hydrogen adsorption close to zero through the electron transfer between them in acidic media, but also provides additional active sites for water dissociation in alkaline solution, both of them being beneficial to the HER performance.

Membrane excitability is a fundamentally important feature for all excitable cells including both neurons and muscle cells. However, the background depolarizing conductances in excitable cells, especially in muscle cells, are not well characterized. Although mutations in transmembrane channel-like (TMC) proteins TMC1 and TMC2 cause deafness and vestibular defects in mammals, their precise action modes are elusive. Here, we discover that both TMC-1 and TMC-2 are required for normal egg laying in C. elegans. Mutations in these TMC proteins cause membrane hyperpolarization and disrupt the rhythmic calcium activities in both neurons and muscles involved in egg laying. Mechanistically, TMC proteins enhance membrane depolarization through background leak currents and ectopic expression of both C. elegans and mammalian TMC proteins results in membrane depolarization. Therefore, we have identified an unexpected role of TMC proteins in modulating membrane excitability. Our results may provide mechanistic insights into the functions of TMC proteins in hearing loss and other diseases.

The important role of edge sites in atomically thin 2D materials serving as catalysts is already of concerned in plenty of material systems and catalytic reactions, whereas comprehensive study of the edge sites in 2D noble‐metal nanocatalysts is still lacking. Herein, for the first time, a controllable etching approach to tailor the fractal dimensions and edge sites of Pd nanosheets is developed and the edge sites in these 2D nanostructures from both structural and chemical aspects are investigated. The as‐tailored 2D Pd nanostructures with extra edge sites exhibit substantially enhanced electrocatalytic performance for the formic acid oxidation reaction (FAOR). Moreover, careful analysis of the results from electrocatalytic measurements reveals that the specific activities for the edge sites in the 2D nanostructures far exceed the activities for the low‐index planes of Pd and even dominate the overall activity exhibited by the 2D noble‐metal catalysts.

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