Covalent organic frameworks (COFs) are crystalline, highly porous, two- or three-dimensional polymers with tunable topology and functionalities. Because of their higher chemical stabilities in comparison to their boron-linked counterparts, imine or β-ketoenamine linked COFs have been utilized for a broad range of applications, including gas storage, heterogeneous catalysis, energy storage devices, or proton-conductive membranes. Herein, we report the synthesis of highly porous and chemically stable acetylene (-C≡C-) and diacetylene (-C≡C-C≡C-) functionalized β-ketoenamine COFs, which have been applied as photocatalyst for hydrogen generation from water. It is shown that the diacetylene moieties have a profound effect as the diacetylene-based COF largely outperforms the acetylene-based COF in terms of photocatalytic activity. As a combined effect of high porosity, easily accessible diacetylene (-C≡C-C≡C-) functionalities and considerable chemical stability, an efficient and recyclable heterogeneous photocatalytic hydrogen generation is achieved.

Long-term treatment with aerosolized iloprost is safe and has sustained effects on exercise capacity and pulmonary hemodynamics in patients with primary pulmonary hypertension.

Yes, we CAN: Partial oxidation of inactive MnO nanoparticles by CeIV as oxidant gives active MnOx catalysts that are suitable for effective photochemical and electrochemical water oxidation. The active MnOx catalyst contains mixed‐valent MnII, MnIII, and MnIV species (see picture; green and violet) interconnected through oxido bridges (red) with defects and disorders. MnOx is analogous to calcium–manganese oxide systems where the calcium sites are replaced by MnII or MnIII ions.

Future advances in renewable and sustainable energy require advanced materials based on earth-abundant elements with multifunctional properties. The design and the development of cost-effective, robust, and high-performance catalysts that can convert oxygen to water, and vice versa, is a major challenge in energy conversion and storage technology. Here we report cobalt oxide nanochains as multifunctional catalysts for the electrochemical oxygen evolution reaction (OER) at both alkaline and neutral pH, oxidant-driven, photochemical water oxidation in various pH, and the electrochemical oxygen reduction reaction (ORR) in alkaline medium. The cobalt oxide nanochains are easily accessible on a multigram scale by low-temperature degradation of a cobalt oxalate precursor. What sets this study apart from earlier ones is its synoptical perspective of reversible oxygen redox catalysis in different chemical and electrochemical environments.

Covalent organic frameworks (COFs) have emerged as an important class of organic semiconductors and photocatalysts for the hydrogen evolution reaction (HER)from water.T oo ptimize their photocatalytic activity,t ypically the organic moieties constituting the frameworks are considered and the most suitable combinations of them are searched for. However,t he effect of the covalent linkage between these moieties on the photocatalytic performance has rarely been studied. Herein, we demonstrate that donor-acceptor (D-A) type imine-linked COFs can produce hydrogen with ar ate as high as 20.7 mmol g À1 h À1 under visible light irradiation, upon protonation of their imine linkages.Asignificant red-shift in light absorbance,largely improved charge separation efficiency,a nd an increase in hydrophilicity triggered by protonation of the Schiff-base moieties in the imine-linked COFs,a re responsible for the improved photocatalytic performance.