Search

Immobilizing platinum (Pt) single atoms on appropriate supports with optimized coordination environments and electronic structures is a promising strategy to address the problem of chlorine corrosion during seawater electrolysis. Herein, Pt single atoms on nickel‐vanadium layered double hydroxides (Pt‐SA/NiV‐LDH) matrix are fabricated for chlorine tolerance hydrogen generation. Due to the strong synergetic electronic interaction between atomically dispersed Pt and the ultrathin NiV LDH matrix, the adsorption/dissociation feature of *H2O, *OH, and *H are optimized as evidenced theoretically. The as‐fabricated Pt‐SA/NiV‐LDH electrode exhibits an exceptional mass activity (i.e., 30.98 times higher) compared to the commercial Pt/C, along with an ultra‐high turnover frequency (TOF) value of 9.90 s−1 in alkaline media. Impressively, only 207 mV overpotential is required to yield a current density of 2000 mA cm‒2 in an electrolyte solution containing 1 m KOH and 2 M NaCl, indicating its robust resistance to chlorine. Moreover, this kind of material demonstrates remarkably low overpotentials of 130 and 215 mV to attain the industrial‐scale current densities of 1000 and 2000 mA cm−2 in alkaline seawater, accompanied by exceptional stability for 500 h working at 500 mA cm−2. This work provides an insightful reference for the production of sustainable green hydrogen through seawater electrolysis. [ABSTRACT FROM AUTHOR]

Lithium–air batteries (LABs) have attracted intense interest due to their ultrahigh energy density. However, the performance of LABs has to depend on modified electrolytes, gas selective film and Li anode protection. In this study, firstly it is reported that Mo‐O octahedron induced subcrystalline scheelite CoMoO4 catalyst achieves a high performance LABs performance based only on the high catalytic activity in air. The subcrystalline CoMoO4 catalyst obtains a specific capacity of 12 000 mAh g−1, and ultralong cycle stability over 270 cycles at 1000 mA g−1 in ambient air. This study demonstrates an ultrastable crystal structure and surface conditions of the CoMoO4 catalyst toward a corrosive environment and complex air‐involved reactions. A theoretical calculation further reveals that the polyhedral framework in the scheelite CoMoO4 can provide a highly stable catalytic surface for the OER/ORR reactions, furthermore, its repulsive nature toward H2O and CO2 can efficiently avoid side reactions and slow the corrosion of the Li anode in air. Moreover, the induced octahedron enhances the adsorption energies to O2 and LiO2, and accelerates the catalytic reactions in air. The present study provides a conceptual breakthrough to find highly active cathode catalysts for LABs. [ABSTRACT FROM AUTHOR]

The oxygen evolution reaction (OER) generally exists in electrochemistry‐enabled applications that are coupled with cathodic reactions like hydrogen evolution, carbon dioxide reduction, ammonia synthesis, and electrocatalytic hydrogenation. The OER heavily impacts the overall energy efficiency of these devices because the sluggish OER kinetics result in a huge overpotential, thus, a large amount of efficient catalysts are needed. The benchmark iridium and ruthenium (Ir/Ru)‐based materials (mostly used in acid media) are, however, significantly limited by their scarcity. Non‐precious metal‐based catalysts (NPMCs) have emerged as the most promising alternatives; however, they tend to degrade quickly under the harsh operating conditions of typical OER devices. Another challenge is the unsatisfying performance of OER catalysts when integrated in real‐world devices. Herein, the OER active sites for three mainstream types of NPMCs including non‐precious transition metal oxides/(oxy)hydroxides, metal‐free carbon materials, and hybrid non‐precious metal and carbon composites are reviewed. In addition, possible degradation mechanisms for active sites and mitigation strategies are discussed in detail. This review also provides insights into the gaps between R&D of NPMCs for the OER and their applications in practical devices. [ABSTRACT FROM AUTHOR]

A facile method to prepare flexible n‐type Ag2Se/Se/polypyrrole (PPy) composite films is developed. First, Ag2Se nanostructures (NSs) are wet chemically synthesized; PPy is then in situ polymerized at the surface of the Ag2Se NSs; and finally, the Ag2Se/Se/PPy composite film on a porous nylon membrane is fabricated by a vacuum‐assisted filtration process followed by hot pressing. An optimal composite film shows an exceptionally high power factor of ≈2240 µW m−1 K−2 at 300 K, mainly because of the synergistic effect between well‐developed crystalline Ag2Se grains and a small amount of Se and PPy. The film also possesses outstanding flexibility (only about 6.5% decrease in electrical conductivity after 1000 times bending along a rod with a radius of 4 mm). Moreover, a flexible thermoelectric generator composed of six legs of the film outputs a voltage of 21.2 mV and a maximum power of 4.04 µW (corresponding power density of 37.6 W m−2) at a temperature difference of 34.1 K, verifying exceptionally high thermoelectric properties. This work shows the promise of the as‐prepared composite film for practical applications in wearable devices and will surely promote the research and development of flexible TE generators. [ABSTRACT FROM AUTHOR]