Covalent organic polymer assisted synthesis of bimetallic electrocatalysts with multicomponent active dopants for efficient oxygen evolution reaction

CoS2 Nanoparticles Embedded in Covalent Organic Polymers as Efficient Electrocatalyst for Oxygen Evolution Reaction with Ultralow Overpotential

Cobalt disulfide (CoS₂ ) has been explored as attractive electrocatalyst for oxygen evolution reaction (OER). However, bulk CoS₂ sheets have limited catalytic activity due to low exposure of active sites. Herein, through an in-situ vulcanization approach, CoS₂ nanoparticles are embedded into bipyridine-containing covalent organic polymer (BP-COP). The as-prepared nanocomposite CoS₂ @BP-COP exhibits high catalytic activity toward OER with an ultra-low overpotential of 270 mV (vs. RHE) at a current density of 10 mA cm^-2 , a small Tafel slope of 36 mV dec^-1 , and an excellent durability for 24 h without decay. The surface of CoS₂ is partially converted into CoOOH to form CoS₂ /CoOOH as active sites under OER conditions. CoS₂ @BP-COP displays superior OER catalytic activity to CoS₂ nanosheets and commercially available RuO₂ under the same conditions. The outstanding OER performance activity of CoS₂ @BP-COP could be attributed to the uniform and small particle sizes of CoS₂ /CoOOH distributed in BP-COP.

Design and Synthesis of Polyimide Covalent Organic Frameworks

As a subseries of the covalent organic framework (COF) material family, polyimide-based covalent organic framework (PI-COF) material, which has the advantages of high stability of polyimide, high specific surface area, and controllable pores of COF material, is expected to be a new type of porous material with potential applications. Although the development of PI-COF is in the early stages during the past decade, it has attracted extensive attention and is widely used in heterogeneous catalysis, gas separation, and storage fields. Therefore, this review is aiming to give a comprehensive understanding of the recent progress of PI-COFs. This article summarizes the progress of PI-COF from three aspects: controllable structure design, synthesis method, and application. First of all, under the guidance of network chemical design principles, the topology type of PI-COF and the size and shape of the formed pores are summarized in terms of different organic monomers. Then the five synthetic strategies for the synthesis of PI-COF are analyzed. Finally, the applications of PI-COF in adsorption and separation, drug delivery, solar-to-electrochemical energy storage, photocatalysis, and electrocatalyst are introduced.

Efficient Carbon Dioxide Electroreduction over Ultrathin Covalent Organic Framework Nanolayers with Isolated Cobalt Porphyrin Units

Electrochemical CO₂ reduction represents a sustainable approach for the conversion of CO₂ into valuable fuels and chemicals. Here, we fabricated a series of composite nanomaterials through template-oriented polymerization of covalent organic frameworks (COFs) with isolated cobalt porphyrin units on amino-functionalized carbon nanotubes for efficient electrocatalytic CO₂ reduction reaction (CO₂RR). Compared with pure COFs, the hybrid form of ultrathin COF nanolayers wrapped on the conductive scaffold leads to distended current density and stable Faradaic efficiency for CO₂-to-CO conversion over a wide potential range. Specifically, the catalytic performances of the system can be finely optimized by the modification of the reticular structure with different functional groups. Our work gives a new strategy for the preparation of highly active and selective electrocatalysts for CO₂RR.

Electron-withdrawing anion intercalation and surface sulfurization of NiFe-layered double hydroxide nanoflowers enabling superior oxygen evolution performance

Unique NiFe-LDH nanoflowers functionalized with electron-withdrawing anion intercalation and surface sulfurization were fabricated, and show superior electrocatalytic activity for the oxygen evolution reaction.