and multifractal turbulence theories. Analysis of the kernels and comparison with experiments reveal that the second kernel results is better agreement with experiments, a more accurate description of the underlying physics and presents the additional advantage of having no fitting constants.

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An ideal porous adsorbent toward uranium with not only large adsorption capacity and high selectivity but also broad applicability even under rigorous conditions is highly desirable but still extremely scarce. In this work, a porous adsorbent, namely [NH 4 ] + [COF‐SO 3 − ], prepared by ammoniating a SO 3 H‐decorated covalent organic framework (COF) enables remarkable performance for uranium extraction. Relative to the pristine SO 3 H‐decorated COF (COF‐SO 3 H) with uranium adsorption capacity of 360 mg g −1 , the ammoniated counterpart of [NH 4 ] + [COF‐SO 3 − ] affords ultrahigh uranium uptake up to 851 mg g −1 , creating a 2.4‐fold enhancement. Such a value is the highest among all reported porous adsorbents for uranium. Most importantly, a large distribution coefficient, K d U , up to 9.8 × 10 6 mL g −1 is observed, implying extremely strong affinity toward uranium. Consequently, [NH 4 ] + [COF‐SO 3 − ] affords highly selective adsorption of uranium over a broad range of metal ions such as S U/Cs = 821, S U/Na = 277, and S U/Sr = 124, making it as effective uranium adsorbent from seawater, resulting in amazing uranium adsorption capacity of 17.8 mg g −1 . Moreover, its excellent chemostability also make it an effective uranium adsorbent even under rigorous conditions (pH = 1, 8, and 3 m acidity).

As a promising renewable alternative to the production of petroleum-derived chemicals and energy, biomass transformation is attracting increasing attention in terms of green chemical processes and sustainable development. Specifically, selective aerobic oxidation of cellulose-derived 5-hydroxymethylfurfural (HMF) into high value-added 2,5-furandicarboxylic acid (FDCA) is regarded as one of the most attractive biomass transformations due to a wide range of its application prospects. Herein, we report the synthesis of a highly efficient and stable bimetallic AuPd nanocatalyst over the La-doped Ca−Mg−Al layered double hydroxide (La-CaMgAl-LDH) support for base-free aerobic oxidation of HMF to FDCA in water, which makes the biomass-based chemical process green and cost effective. Under optimized reaction conditions, the yield of FDCA can reach above 99%. Such encouraging performance of the catalyst is believed to be correlated with both the higher surface basicity of La-CaMgAl-LDH support and the synergy between Au−Pd atoms in the bimetallic AuPd nanoparticles, which can greatly favor the activation of reactants and reaction intermediates in the course of tandem oxidation reactions. The present work provides an effective strategy for developing highly efficient bimetallic catalysts with the enhanced stability by adjusting surface structures and compositions of supports for a wide range of base-free aerobic oxidation of other biomass-derived compounds in water.

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