Hybrid Zeolitic Imidazolate Frameworks for Promoting Electrocatalytic Oxygen Evolution via a Dual-Site Relay Mechanism.

Developing efficient oxygen evolution reaction (OER) electrocatalysts is important for enhancing the water splitting efficiency. However, with the current catalysts containing one kind of active sites, it is challenging to achieve low overpotentials because of the four-electron transfer process. Herein is reported HZIF-2-CoMo, a new metal-organic framework with well-defined Co-Mo dual sites that can promote the OER process through an unconventional Mo6+/Co2+ dual-site relay mechanism. Theoretical calculations suggested that the Mo and Co sites stabilize the HO* and HOO* intermediates, respectively, and that the unique Co-O-Mo configuration induces the formation of a Co-O*-Mo transition intermediate, remarkably reducing the reaction free energy. As a result, HZIF-2-CoMo shows an overpotential of 277 mV at 10 mA cm-2 and a low Tafel slope of 70 mV dec-1 in alkaline solution, making it one of the best OER electrocatalysts reported to date.

NH4 Be2 BO3 F2 and γ-Be2 BO3 F: Overcoming the Layering Habit in KBe2 BO3 F2 for the Next-Generation Deep-Ultraviolet Nonlinear Optical Materials.

KBe2 BO3 F2 (KBBF) is still the only practically usable crystal that can generate deep-ultraviolet (DUV) coherent light by direct second harmonic generation (SHG). However, applications are hindered by layering, leading to difficulty in the growth of thick crystals and compromised mechanical integrity. Despite efforts, it is still a great challenge to discover new nonlinear optical (NLO) materials that overcome the layering while keeping the DUV SHG available. Now, two new DUV NLO beryllium borates have been successfully designed and synthesized, NH4 Be2 BO3 F2 (ABBF) and γ-Be2 BO3 F (γ-BBF), which not only overcome the layering but also can be used as next-generation DUV NLO materials with the shortest type I phase-matching second-harmonic wavelength down to 173.9 nm and 146 nm, respectively. Significantly, γ-BBF is superior to KBBF in all metrics and would be the most outstanding DUV NLO crystal.

Construction of unprecedented pillar-layered metal organic frameworks via a dual-ligand strategy for dye degradation.

A dual-ligand strategy is used to construct two pillar-layered metal organic frameworks (MOFs) with [Zn2(COO)3]+ subunits (SBUs) and [ZnxCo3-x(ethanol)2(COO)4]2+ SBUs, respectively. Remarkably, the Zn/Co mixed compound 2 exhibits excellent and adjustable photocatalytic activity to degrade crystal violet (CV) in water under visible light.

Collaborative enhancement from Pb2+ and F- in Pb2(NO3)2(H2O)F2 generates the largest second harmonic generation effect among nitrates.

The first metal nitrate fluoride nonlinear optical material, Pb2(NO3)2(H2O)F2, was synthesized with the largest second harmonic generation (SHG) effect (12 × KH2PO4) among nitrates. Theoretical calculations revealed the synergistic effect of [NO3]-, lone pair electrons in Pb2+, and F- for the SHG effect. The F- also promoted the blue-shift of the ultraviolet cut-off edge.

Diverse tetrahedral tetrazolate frameworks with N-rich surface.

Three tetrahedral tetrazolate frameworks (TTFs) with SOD, and topologies (TTF-4, -5 and -6) are obtained by using the anion and solvent as structure-directing agents. The resulting SOD-type TTF-4 shows high chemical stability as well as high CO2 uptake capacity.

Achievement of Bulky Homochirality in Zeolitic Imidazolate-Related Frameworks.

Before this work, adding chiral C centers into zeolitic imidazolate frameworks (ZIFs) has never been realized. Presented here are the first examples on achieving bulky homochirality in ZIF systems, and three homochiral zeolitic imidazolate-related frameworks with sodalite and dia topologies are successfully synthesized by employing enantiopure imidazolate derivatives. The results open a new blueprint on the synthetic design of homochiral ZIFs for future applications.