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.

A fast and facile route for the optimization of covalent triazine frameworks (CTFs) for photocatalytic hydrogen production is presented. Within 10 minutes a CTF with low photocatalytic activity can be converted into a highly active photocatalyst. Optimized CTF catalysts show an average hydrogen evolution rate of 1072 μmol h g under visible light (>420 nm).

The mechanistically distinct and synergistic role of phosphite anions in hydrogen evolution and nickel cations in oxygen evolution have been uncovered for active and durable overall water splitting catalysis in nickel phosphite.

Over the years, cobalt phosphates (amorphous or crystalline) have been projected as one of the most significant and promising classes of nonprecious catalysts and studied exclusively for the electrocatalytic and photocatalytic oxygen evolution reaction (OER). However, their successful utilization of hydrogen evolution reaction (HER) and the reaction of overall water-splitting is rather unexplored. Herein, presented is a crystalline cobalt phosphate, Co 3 (OH) 2 (HPO 4 ) 2 , structurally related to the mineral lazulite, as an efficient precatalyst for OER, HER, and water electrolysis in alkaline media. During both electrochemical OER and HER, the Co 3 (OH) 2 (HPO 4 ) 2 nanostructure was completely transformed in situ into porous amorphous CoO x (OH) films that mediate efficient OER and HER with extremely low overpotentials of only 182 and 87 mV, respectively, at a current density of 10 mA cm −2 . When assemble as anode and cathode in a two-electrode alkaline electrolyzer, unceasing durability over 10 days is achieved with a final cell voltage of 1.54 V, which is superior to the recently reported effective bifunctional electrocatalysts. The strategy to achieve more active sites for oxygen and hydrogen generation via in situ oxidation or reduction from a well-defined inorganic material provides an opportunity to develop cost-effective and efficient electrocatalysts for renewable energy technologies.