Enhanced Production of Formic Acid in Electrochemical CO2 Reduction over Pd-Doped BiOCl Nanosheets.

Bismuth oxyhalides (BiOX, X = F, Cl, Br, I) are emerging energy materials because of their remarkable catalytic activity. The BiOX compounds usually have a tetragonal type crystal structure with unique layered morphology consisting of [X-Bi-O-Bi-X] sheets. Although the BiOX nanosheets exposed with {001} facets perform superior photoactivity, there is lack of understanding about their capability in the electrochemical CO2 reduction reaction (CO2RR). Herein, we adopt wet-chemical syntheses to make 2D BiOCl and Pd-doped BiOCl nanosheets for CO2RR. In the results, formic acid is the only one kind of product converted from CO2 along with H2 gas from water reduction over both BiOCl and Pd-doped BiOCl nanosheets. By thorough analyses with ex situ and in situ spectroscopy, the results reflect that (1) metallic Bi0 atoms generated by the applied negative potentials serve as the catalytic sites for the hydrogen evolution reaction (HER) and CO2RR and (2) the existence of doped Pd ions in the BiOCl structure reduces the barrier of charge transfer over the nanosheets, which enhances HER and CO2RR activities. We believe that the observations are important references for making catalysts toward CO2RR performance.

Rare metal-ion metathesis of a tetrahedral Zn(ii) core of a noncentrosymmetric (3,4)-connected 3D MOF.

An SHG-active noncentrosymmetric (3,4)-connected Zn(ii)-organic framework, {[Zn2(4-abpt)(3,4-pydc)2]·2DMAc·3MeOH·H2O}n (1-Zn), was synthesized using a mixed-ligand system. The 1-Zn framework undergoes metal metathesis, with the complete exchange of the tetrahedrally coordinated ZnII ions with CuII ions while retaining the integrity of the network.

A Series of Organic-Inorganic Hybrid Zinc Phosphites Containing Extra-Large Channels.

A series of organic-inorganic hybrid zinc phosphites with extra-large channels were synthesized and characterized by single-crystal X-ray diffraction. This is an unusual example of introducing 1,4-benzenedicarboxylate and/or biphenyl-4,4'-dicarboxylate ligands into the organically templated metal phosphite system to build extra-large-channel zeolite-related materials via hydro(solvo)thermal reactions. Those frameworks are composed of carboxylate linkers and inorganic tubes of zinc phosphites, translating their channel windows from a square shape (NTOU-1) to rhombus forms (NTOU-2 and NTOU-3) via the replacement of organic amines or ligands under synthesis conditions otherwise identical with those used to prepare NTOU-1. The synthesis, structural diversity, photoluminescence, and adsorption properties for dye molecules and lanthanide ions are also reported.

Two Polymorphs of an Organic-Zincophosphate Incorporating a Terephthalate Bridging Ligand in an Unusual Bonding Mode.

Two new polymorphs of a zinc phosphate incorporating the terephthalate organic ligand 1,4-benzenedicarboxylate (BDC), (H2DA)Zn2(cis-BDC)(HPO4)2 (1) and (H2DA)Zn2(trans-BDC)(HPO4)2 (2), where DA = 1,7-diaminoheptane, were synthesized via a hydro(solvo)thermal method at different reaction temperatures and structurally characterized by single-crystal X-ray diffraction. Interestingly, the BDC ligands, which adopt the bis-monodentate coordination model with a unusual cis type for compound 1 and with a trans linkage for compound 2, bridge the Zn atoms of the inorganic layers in the generation of two polymorphs with structural diversities (one kind of arrangement of the layered zincophosphate layer in 1; the flat and zigzag sheets of inorganic networks in 2). A simple method for tuning the optical luminescence of the title compound from blue, red, green, yellow, and pink to white emission by stirring powdered samples in lanthanide-cation-containing aqueous ethanol solutions at room temperature for 1-2 h is also presented.