Comparison of two water oxidation electrocatalysts by copper or zinc supermolecule complexes based on porphyrin ligand

Fabrication of a self-standing supramolecular membrane by a "soft spray" technique

We report a one-step method to fabricate a free-standing supramolecular membrane composed of melamine and barbituric acid coordinated with silver nitrate (Mba-Ag) at the gas/liquid interface by a soft spray technique. MBa-Ag exhibits a folded two-dimensional layered morphology and thickness of 4.5 μm. The shortwave IR transmittance of MBa-Ag is as high as 95%, which is much higher than the transmittance of UV and visible light, and has the potential for electromagnetic wave transmission.

Mapping the electrocatalytic water splitting activity of VO2 across its insulator-to-metal phase transition

The electrocatalytic water splitting activity of V-based oxides has been rarely investigated, even though several polymorphs in VO₂ are expected to exhibit different electrocatalytic activities depending on their crystal and electronic structures. The rutile structure of VO₂(R), showing metallic character, is a good candidate for a new electrocatalyst since it undergoes insulator-to-metal transition (IMT) from the insulating VO₂(M1) at a low temperature of 68 °C, and involves a substantially increased electrical conductivity by three orders of magnitude. The extensive improvements in the electrocatalytic activity for both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) are confirmed when the IMT is induced where the overpotential (η₁₀) is reduced from 1056 mV to 598 mV in the OER and 411 mV to 136 mV in the HER, respectively. This improvement is attributed to the increased electrochemically active surface area (ECSA), reduced charge transfer resistance, and increased electron density, driven by the IMT to the metallic VO₂(R) phase.

Porphyrin-based frameworks for oxygen electrocatalysis and catalytic reduction of carbon dioxide

The recent progress made on porphyrin-based frameworks and their applications in energy-related conversion technologies (e.g., ORR, OER and CO₂RR) and storage technologies (e.g., Zn–air batteries).

Structure and photophysical and electrochemical properties of a copper porphyrin complex with a three-dimensional framework

Porphyrins and metalloporphyrins can generally show attractive structural motifs and interesting properties. A new copper porphyrin, namely poly[[μ-chlorido-[μ₅-5,10,15,20-tetrakis(pyridin-4-yl)-21H,23H-porphine]tricopper(I)] [aquadichloridocopper(II)]], {[Cu₃(C₄₀H₂₄N₈)Cl][CuCl₂(H₂O)]}_n (1), was synthesized by the self-assembly of copper chloride with 5,10,15,20-tetrakis(pyridin-4-yl)-21H,23H-porphine under solvothermal conditions. The structure of this copper porphyrin was characterized by single-crystal X-ray crystallography and elemental analysis. The porphyrin macrocycle shows a distorted saddle geometry, with the four pyrrole rings slightly distorted in an alternating mode either upwards or downwards. The copper ions show three-coordinated triangular and four-coordinated square-planar geometries. Every copper-porphyrin unit connects to 12 others via four μ₄-bridging Cu₂Cl moieties to complete the three-dimensional framework of compound 1, with isolated CuCl₂(H₂O) units located in the voids. This copper porphyrin displays a red photoluminescence. Electrochemical measurements showed that compound 1 has two redox waves (E_1/2 = -160 and 91 mV).

A sandwich-type catalytic composite reassembled with a birnessite layer and metalloporphyrin as a water oxidation catalyst

Sandwich-type MnTAPP@bir was synthesized by re-assembly of exfoliated birnessite and MnTAPP, and exhibited superior OER performance.