An Elastic Monolithic Catalyst: A Microporous Metalloporphyrin‐Containing Framework‐Wrapped Melamine Foam for Process‐Intensified Acyl Transfer

Non-Precious Metal-Doped Carbon Materials Derived From Porphyrin-Based Porous Organic Polymers for Oxygen Reduction Electrocatalysis

The cathodic oxygen reduction reaction (ORR) is important in the development of renewable energy devices, to produce novel and non-precious metal catalysts with high electrocatalytic activity to reduce the consumption of non-renewable platinum (Pt) catalyst. In this work, we developed N-doped and Fe/N dual-doped porous carbons as catalysts for ORR simply by high-temperature pyrolysis of porphyrin-based conjugated microporous polymers (CMPs). By combination of heteroatom doping, highly porous structure and tubular morphology, the as-prepared carbon samples exhibited high electrocatalytic activity with 4-electron transfer mechanism, nearly close to the commercial Pt/C catalyst. In particular, among these samples, the Fe/N-CMP-1000 displayed a higher onset potential (0.95 eV), positive half-wave potential (0.85 eV) and limiting current density value (5.1 mA cm^-2 ) as well as good durability and better methanol tolerance contrasting with Pt/C catalyst, suggesting that the as-prepared metal-free catalysts from porphyrin-based CMPs show great potential for ORR.

NaCl template-assisted synthesis of self-floating COFs foams for the efficient removal of sulfamerazine

The preparation of hierarchical porous covalent organic frameworks (HP-COFs) is of great significance due to their inherent porosity and low density. However, it is still very challenging owing to the poor machinability of COFs. Herein, a simple and cost-efficient strategy for the synthesis of HP-COFs was proposed. In particular, p-toluenesulfonic acid and NaCl, both of which can be recycled, are utilized as catalyst and template, respectively. The resulting HP-TpBD-900 featuring abundant macropore and mesopore as well as large specific surface area (~700 m² g^-1) possessed self-floating ability and was turned out to be a promising adsorbent for the efficient removal of sulfamerazine (SMR) in aqueous solution. The maximum adsorption capacity is 168 mg g^-1, which is more than twice in comparison to that of material prepared without NaCl template. In addition, no significant decrease in adsorption capacity was observed after 5 cycles. Furthermore, the density functional theory (DFT) method was utilized to elucidate the adsorption mechanism, which could be dominated by hydrogen bonding and C-H···π interaction. This work not only provides a new strategy for the synthesis of HP-COFs, but also contributes to boosting the application of COFs in the field of wastewater treatment.

Efficient and Selective Methane Borylation Through Pore Size Tuning of Hybrid Porous Organic-Polymer-Based Iridium Catalysts

As a new energy source that could replace petroleum, the global reserves of methane hydrate (combustible ice) are estimated to be approximately 20 000 trillion cubic meters. A large amount of methane hydrate has been found under the seabed, but the transportation and storage of methane gas far from coastlines are technically unfeasible and expensive. The direct conversion of methane into value-added chemicals and liquid fuels is highly desirable but remains challenging. Herein, we prepare a series of iridium complexes based on porous polycarbazoles with high specific areas and good thermochemical stabilities. Through structure tuning we optimized their catalytic activities for the selective monoborylation of methane. One of these catalysts (CAL-3-Ir) can produce methyl boronic acid pinacol ester (CH₃ Bpin) in 29 % yield in 9 h with a turnover frequency (TOF) of approximately 14 h^-1 . Because its pore sizes favor monoborylated products, it has a high chemoselectivity for monoborylation (CH₃ Bpin:CH₂ (Bpin)₂ =16:1).