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The separation of actinides has a vital place in nuclear fuel reprocessing, recovery of radionuclides, and remediation of environmental contamination. Here we propose a new paradigm of nanocluster-based actinide separation, namely, nanoextraction, that can achieve efficient sequestration of uranium in an unprecedented form of giant coordination nanocages using a cone-shaped macrocyclic pyrogallol[4]arene as the extractant. The U24-based hexameric pyrogallol[4]arene nanocages with distinctive [U2(PG)2] binuclear units (PG = pyrogallol) that rapidly assembled in situ in monophasic solvent were identified by single-crystal X-ray diffraction, MALDI-TOF mass spectrometry, NMR spectroscopy, and small-angle X-ray and neutron scattering. Comprehensive biphasic extraction studies showed that this novel separation strategy has enticing advantages such as fast kinetics, high efficiency, and good selectivity over lanthanides, thereby demonstrating its potential for efficient separation of actinide ions.

Efficient transfer of charge carriers through a fast transport pathway is crucial to excellent photocatalytic reduction performance in solar-driven CO 2 reduction, but it is still challenging to effectively modulate the electronic transport pathway between photoactive motifs by feasible chemical means. In this work, we propose a thermally induced strategy to precisely modulate the fast electron transport pathway formed between the photoactive motifs of a porphyrin metal-organic framework using thorium ion with large ionic radius and high coordination number as the coordination-labile metal node. As a result, the stacking pattern of porphyrin molecules in the framework before and after the crystal transformations has changed dramatically, which leads to significant differences in the separation efficiency of photogenerated carriers in MOFs. The rate of photocatalytic reduction of CO 2 to CO by IHEP-22(Co) reaches 350.9 μmol·h -1 ·g -1 , which is 3.60 times that of IHEP-21(Co) and 1.46 times that of IHEP-23(Co) . Photoelectrochemical characterizations and theoretical calculations suggest that the electron transport channels formed between porphyrin molecules inhibit the recombination of photogenerated carriers, resulting in high performance for photocatalytic CO 2 reduction. The interaction mechanism of CO 2 with IHEP-22(Co) was clarified by using in-situ electron paramagnetic resonance, in-situ diffuse reflectance infrared Fourier transform spectroscopy, in-situ extended X-ray absorption fine structure spectroscopy, and theoretical calculations. These results provide a new method to regulate the efficient separation and migration of charge carriers in CO 2 reduction photocatalysts and will be helpful to guide the design and synthesis of photocatalysts with superior performance for the production of solar fuels.