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NiFe layered double hydroxides (LDHs) have been denoted as benchmark non-noble-metal electrocatalysts for the oxygen evolution reaction (OER). However, for laminates of NiFe LDHs, the edge sites are active, but the basal plane is inert, leading to underutilization as catalysts for the OER. Herein, for the first time, light and electron-deficient Li ions are intercalated into the basal plane of NiFe LDHs. The results of theoretical calculations and experiments both showed that electrons would be transferred from near Ni2+ to the surroundings of Li+ , resulting in electron-deficient properties of the Ni sites, which would function as "electron-hungry" sites, to enhance surface adsorption of electron-rich oxygen-containing groups, which would enhance the effective activity for the OER. As demonstrated by the catalytic performance, the Li-NiFe LDH electrodes showed an ultralow overpotential of only 298 mV at 50 mA cm-2 , which was lower than that of 347 mV for initial NiFe LDHs and lower than that of 373 mV for RuO2 . Reasonable intercalation adjustment effectively activates laminated Ni2+ sites and constructs the electron-deficient structure to enhance its electrocatalytic activity, which sheds light on the functional treatment of catalytic materials.

Organic anions of two benzenepolycarboxylic acids [1,3,5-benzenetricarboxylic acid (BTA) and 2,2′-biphenyldicarboxylic acid (BDA)], two pyridinecarboxylic acids [quinolinic acid (QA) and 2,5-pyridinedicarboxylic acid (PDA)], and two amino acids [phenylalanine (Phe) and tyrosine (Tyr)] were intercalated into the galleries of NO3–-type layered europium hydroxide (NO3–LEuH). All the prepared products displayed XRD patterns with series of diffractions due to layered materials. The composite structures and the arrangement of the guests in the galleries were investigated in detail. The structure of the organic guests (such as the number and position of carboxyl groups) affects the arrangement in the interlayer. SEM observations showed that the NO3–LEuH precursor and its intercalates crystallize in a columnar or layered stacking structure composed of hexagonal thin platelets. The luminescence study indicated that all samples display the typical red emission of Eu3+. Efficient energy transfer between intercalated BTA/BDA anions and Eu3+ centers takes place, markedly enhancing the Eu3+ luminescence, whereas QA–LEuH and PDA–LEuH with pyridinedicarboxylic acid anions show no obvious change in luminescence intensity. When amino acid anions such as Phe and Tyr were introduced into the interlayer, the Eu3+ emission was strongly quenched. The simple soft chemical method can open great opportunities for developing organic–inorganic multifunctional luminescent materials or biological probes for detecting certain amino acids.

Co-assembly of inorganic LDH nanosheets with an organic azacrown ether carboxylic acid derivative was studied by a flocculation method. The homogeneous structure seen in the wet state changed markedly after drying: a staging structure transformed into a homogeneous one after increased assembly times. The experimental observations, changeover from homogeneous to staging and unequal charges of organic and inorganic guests in gallery, might suggest the Daumas–Herold model applicable in LDH system. The composites with staging could function as powerful water adsorption materials with facile reversibility.

The organic sensitizer terephthalic acid and its anion terephthalate (TA) were introduced into the galleries of europium-doped layered yttrium hydroxide (LYH:Eu). In contrast to using water as solvent, the use of formamide resulted in the introduction of more organic guests and markedly enhanced the Eu3+ luminescence. Formamide prevented water from entering the system, leading to an excess of terephthalic acid molecules, and more efficient coordination of the TA guest with the Eu3+ in the layers of the composite, all of which may have contributed to the enhanced Eu3+ luminescence.

Novel Co-Cu complex nanorods with diameters of 100-200 nm and nanorings with a ring-diameter of 80 nm were synthesized via a microemulsion method at room temperature. Using this method, the addition of Co(NH3)(3+)6 to aqueous solutions of Cu(ii) in excessive carbonate promotes the assembly of a new highly charged carbonato-copper(ii) anion, [Cu4(OH)(CO3)8]9-.