Engineering of HO-Zn-N2 Active Sites in Zeolitic Imidazolate Frameworks for Enhanced (Photo)Electrocatalytic Hydrogen Evolution.

Currently, lack of ways to engineer specific and well-defined active sites in zeolitic imidazolate frameworks (ZIFs) limits our fundamental knowledge with respect to the mechanistic details for (photo)electrocatalytic hydrogen evolution reaction (HER). Here, we introduce the open metal sites into ZIFs through the selective ligand removal (SeLiRe) strategy, comprehensively characterize the altered structural and electronic features, and evaluate their role in HER. In-situ electrochemical analysis and X-ray absorption spectroscopy reveal the formation of high-valence HO-Zn-N2 sites through the binding of Zn-N2 with electrolyte hydroxide.

Ligand engineering enhances (photo) electrocatalytic activity and stability of zeolitic imidazolate frameworks via in-situ surface reconstruction.

The current limitations in utilizing metal-organic frameworks for (photo)electrochemical applications stem from their diminished electrochemical stability. In our study, we illustrate a method to bolster the activity and stability of (photo)electrocatalytically active metal-organic frameworks through ligand engineering. We synthesize four distinct mixed-ligand versions of zeolitic imidazolate framework-67, and conduct a comprehensive investigation into the structural evolution and self-reconstruction during electrocatalytic oxygen evolution reactions.

Harnessing a Ti-based MOF for selective adsorption and visible-light-driven water remediation.

In pursuit of universal access to clean water, photocatalytic water remediation using metal-organic frameworks (MOFs) emerges as a strong alternative to the current wastewater treatment methods. In this study, we explore a unique Ti-based MOF comprised of 2D secondary-building units (SBUs) connected biphenyl dicarboxylic acid (Hbpdc) ligands - denoted as COK-47 - as a visible-light-driven photocatalyst for organic dye degradation. Synthesized a recently developed microwave-assisted method, COK-47 exhibits high hydrolytic stability, demonstrates a strong dye uptake, and shows noteworthy dye-degradation performance under UV, visible, and solar light, outperforming benchmark TiO and MIL-125-Ti photocatalysts.

MOCHAs: An Emerging Class of Materials for Photocatalytic H Production.

Production of green hydrogen (H) is a sustainable process able to address the current energy crisis without contributing to long-term greenhouse gas emissions. Many Ag-based catalysts have shown promise for light-driven H generation, however, pure Ag-in its bulk or nanostructured forms-suffers from slow electron transfer kinetics and unfavorable Ag─H bond strength. It is demonstrated that the complexation of Ag with various chalcogenides can be used as a tool to optimize these parameters and reach improved photocatalytic performance.

Silicon Oxycarbide (SiOC)-Supported Ionic Liquids: Heterogeneous Catalysts for Cyclic Carbonate Formation.

Silicon oxycarbides (SiOCs) impregnated with tetrabutylammonium halides (TBAX) were investigated as an alternative to silica-based supported ionic liquid phases for the production of bio-based cyclic carbonates derived from limonene and linseed oil. The support materials and the supported ionic liquid phases (SILPs) were characterized via Fourier transform infrared spectroscopy, thermogravimetric analysis, nitrogen adsorption, X-ray photoelectron spectroscopy, microscopy, and solvent adsorption. The silicon oxycarbide supports were pyrolyzed at 300-900 °C prior to being coated with different tetrabutylammonium halides and further used as heterogeneous catalysts for the formation of cyclic carbonates in batch mode.

Microwave-assisted synthesis of metal-organic chalcogenolate assemblies as electrocatalysts for syngas production.

Today, many essential industrial processes depend on syngas. Due to a high energy demand and overall cost as well as a dependence on natural gas as its precursor, alternative routes to produce this valuable mixture of hydrogen and carbon monoxide are urgently needed. Electrochemical syngas production via two competing processes, namely carbon dioxide (CO) reduction and hydrogen (H) evolution, is a promising method.

Are Polyaniline and Polypyrrole Electrocatalysts for Oxygen (O) Reduction to Hydrogen Peroxide (HO)?

In this report, we present results on the electrocatalytic activity of conducting polymers [polyaniline (PANI) and polypyrrole (PPy)] toward the electrochemical oxygen reduction reaction (ORR) to hydrogen peroxide (HO). The electropolymerization of the polymers and electrolysis conditions were optimized for HO production. On flat glassy carbon (GC) electrodes, the faradaic efficiency (FE) for HO production was significantly improved by the polymers.