Conversing oxygen (O2) to hydrogen peroxide (H2O2) driven by solar energy is a promising H2O2 onsite production route but often short of efficient and durable photocatalysts. Herein, strong π–π conjugate polycyclic aromatic benzene and acetylene units have been constructed into new covalent organic frameworks (COFs) linked by imine CN bonding. These COFs demonstrated two-dimensional hexagonal crystalline frameworks with higher crystallinity and larger surface area (>600 m2 g–1). Covalent benzene–acetylene frameworks possessed appropriate visible light-responsive band structure and the suppressed charge recombination rate. The −OH groups on their frameworks enable them to be weakly hydrophilic. As a result, it served as high-performance but durable photocatalysts for H2O2 production in the water–benzyl alcohol (BA) two-phase system. It delivered a H2O2 production rate of 1240 μmol h–1 gcat –1 and durable catalytic efficiency within 60 h, comparable to the best COF-based catalysts. This study provides an efficient two-phase photocatalytic system for H2O2 production based on weakly hydrophilic imine-linked benzene–acetylene organic photocatalysts.

Molecular engineering-tuned covalent organic frameworks (COFs) have demonstrated as the promising photocatalysts for photocatalytic hydrogen peroxide (H2O2) production by two-electron oxygen reduction in water. Herein a simple strategy by altering...

Photocatalytic H2O2 production by conversion of O2 in aqueous solution is often challenged by the use of sacrificial agents, the separation of powdery photocatalysts, solution, and contaminants, and low activity of photocatalyst. Herein, a membrane of covalent furan‐benzimidazole‐linked polymer (Furan‐BILP) with both O‐ and N‐containing heterocycles bonded via OCCN is reported for the first time as a photocatalyst to harvest clean H2O2 in pure water with high‐performance. A coordination‐polymer hard template strategy is developed to produce Furan‐BILP hollow microfibers that can be further assembled into membranes with desired sizes. The resultant Furan‐BILP membrane directly delivers clean H2O2 solution as the product with a high H2O2 production rate of 2200 µmol g−1 h−1 in pure water. Density functional theory calculations and experiment results indicate that the C atom from Furan ring on the linkage binds to the adsorbed OOH*, the H atom of OOH* forms a hydrogen bond with the N atom in the benzimidazole ring, thus the intermediate six‐membered ring structure stabilizes the OOH* and favors 2e‐ORR. The strategy using both molecular engineering to tune the electronic structure and macrostructural engineering to shape the morphology may be applied to design other coordination organic polymer photocatalysts with further improved performance.

Significant noise suppression for magnetohydrodynamics (MHD) mode characterization in the spatial and spectral domain is achieved by processing two-dimensional (2D) electron cyclotron emission imaging (ECEI) data with a one-dimensional (1D) ECEI technique using a short time window ( 1 ms ). The technique is applied to detect toroidal Alfven eigenmodes (TAEs) in the temporal spectrum and fit their radial envelope using the data from the DIII-D tokamak W-band 2D ECEI system. Using the data length (time window) of only 1 ms , the 1D ECEI can clearly detect the TAEs (∼100 kHz ) on the spectrum, while similar spectrum quality requires ∼10 ms data length with the cross power spectrum between two midplane ECEI channels. The 1D ECEI technique also effectively avoids biased fitting when resolving the fine structure of the TAE’s radial envelope. The radially spatial resolution of 1D ECEI is constrained by the finite ECE radiation volume of the ECEI receiver. With forward radiation modeling, we find the DIII-D ECEI system can sensitively measure the even parity MHD activities, for which the mode width is >15 mm, and tearing modes (odd parity MHD activities), for which the island full width is >30 mm.

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A soft-pyrolysis strategy by heating Co-N-implanted covalent organic polymer combining on carbon nanotubes at ≤500 °C has been developed to obtain efficient Co-N-C electrocatalysts for oxygen reduction reaction (ORR). The prepared Co-N-C is highly active for ORR with a half-wave potential of 0.91 V versus RHE in 0.1 M KOH electrolyte, superior to most of previously reported Co-based electrocatalysts. When employing it as cathode electrocatalyst, the homemade Zn-air battery shows a peak power density of 304.2 mW cm À2 , comparable to the parallel power density (250 mW cm À2 ) of Zn-air battery with Pt/C (20 wt%) electrocatalyst at cathode. The soft-pyrolysis strategy not only helps to generate high density Co-N x active sites on carbons but also facilitates the optimizing balance between active site densities, graphitization degree, and pore structure of Co-N-C catalysts. Herein, a simple and energy-effective low-temperature pyrolysis strategy to obtain high-performance ORR electrocatalyst is provided.