The
limitations of the Haber–Bosch reaction, particularly
high-temperature operation, have ignited new interests in low-temperature
ammonia-synthesis scenarios. Ambient N2 electroreduction
is a compelling alternative but is impeded by a low ammonia production
rate (mostly <10 mmol gcat
–1 h–1), a small partial current density (<1 mA cm–2), and a high-selectivity hydrogen-evolving side reaction.
Herein, we report that room-temperature nitrate electroreduction catalyzed
by strained ruthenium nanoclusters generates ammonia at a higher rate
(5.56 mol gcat
–1 h–1) than the Haber–Bosch process. The primary contributor to
such performance is hydrogen radicals, which are generated by suppressing
hydrogen–hydrogen dimerization during water splitting enabled
by the tensile lattice strains. The radicals expedite nitrate-to-ammonia
conversion by hydrogenating intermediates of the rate-limiting steps
at lower kinetic barriers. The strained nanostructures can maintain
nearly 100% ammonia-evolving selectivity at >120 mA cm–2 current densities for 100 h due to the robust subsurface Ru–O
coordination. These findings highlight the potential of nitrate electroreduction
in real-world, low-temperature ammonia synthesis.
Minimum mortality temperature (MMT) is an important indicator to assess the temperature-mortality relationship. It reflects human adaptability to local climate. The existing MMT estimates were usually based on case studies in data rich regions, and limited evidence about MMT was available at a global scale. It is still unclear what the most significant driver of MMT is and how MMT will change under global climate change. Here, by analysing MMTs in 420 locations covering six continents (Antarctica was excluded) in the world, we found that although the MMT changes geographically, it is very close to the local most frequent temperature (MFT) in the same period. The association between MFT and MMT is not changed when we adjust for latitude and study year. Based on the MFT~MMT association, we estimate and map the global distribution of MMTs in the present (2010s) and the future (2050s) for the first time.
The peroxidase-like activity of graphitic carbon nitride (g-C3N4) is dramatically increased by a small cobalt doping. The cobalt-doped g-C3N4 was used for wastewater treatment, exhibiting much higher degradation rate than that of pure g-C3N4.
Novel hierarchical NiO nanoflowers assembled by ultrathin nanoflakes were found to exhibit intrinsic superoxide dismutase-like activity for the first time.
Li5FeO4, as a high-capacity built-in pre-lithiation reagent, has attracted wide interest due to its attractive characteristics, such as extremely higher capacity and energy density, low cost, and environmental friendliness. However, the preparation technology of high-stability Li5FeO4 remains a great challenge. Here, we report a highly air-stable Li5FeO4 cathode pre-lithiation reagent by the solid-phase method. The Li5FeO4 is coated with Li6CoO4 (Li6CoO4@Li5FeO4, referred to as LCO@LFO), which can effectively improve the stability of Li5FeO4 materials under ambient atmosphere and significantly enhance the electrochemical performance. The material possesses an initial charge capacity of 518.8mAh g−1 when charged to 4.5 V and exhibits good air-filled capacity retention. Besides, the LiNi0.8Co0.1Mn0.1O2 (NCM811) full-cell with 5 wt% LCO@LFO additive has an initial discharging capacity of 205 mAh g−1 in the charge and discharge interval of 2.0 V–4.5 V (vs Li+/Li), respectively, higher than the initial discharging capacity of 166.5 mAh g−1 of pure NCM811. The reversible specific capacity of the NCM811 with LCO@LFO cathode in the full cell can be increased by 8.8%, which is equivalent to a 14.35% increase in energy density. Our research report opens a door for the commercial application of LCO@LFO, a high-stability cathode composite pre-lithiation reagent.
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