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On the premise of cleanliness and stability, improving the catalytic efficiency for the oxygen reduction reaction in the electrode reaction of fuel cells and metal-air batteries is of vital importance. Studies have shown that heteroatom doping and structural optimization are efficient strategies. Herein, a single-atom-like B-N3 configuration in carbon is designed for efficient oxygen reduction reaction catalysis inspired by the extensively studied transition metal M-Nx sites, which is supported on the ordered macroporous carbon prepared by utilizing a hydrogen-bonded organic framework as carbon and nitrogen sources and SiO2 spheres as a template. The co-doping of B/N and ordered macroporous structures promote the metal-free material high oxygen reduction catalytic performance in alkaline media. DFT calculations reveal that the B-N3 structure played a key role in enhancing the oxygen reduction activity by providing rich favorable *OOH and *OH adsorption sites on the B center. The promoted formation of *OH/*OOH intermediates accelerated the electrocatalyst reaction. This study provides new insights into the design of single-atom-like nonmetallic ORR electrocatalysts and synthesis of ordered macroporous carbons based on hydrogen-bonded organic frameworks.

In the development of proton conductors, it is very important to increase the density of proton carriers to adjust proton conduction pathways. In this work, two novel isomeric hydrogen-bonded organ...

We report the development of a new type of organic semiconductor gas sensor based on a porphyrin-based hydrogen-bonded organic framework (HOF). Owing to the orderly porous structures, the decoration with rich amino sites and the n-type semiconductor nature, this HOF-based sensor exhibits selective NO2 sensing performance with ultra-fast response/recovery rates (17.6 s/15.4 s over 100 ppb) and a limit of detection lower than 40 ppb, together with high sensitivity, good reproducibility, and long-term stability at room temperature. This study demonstrates that HOF-based materials have potential application prospects in gas sensing, thereby offering a new way of thinking for the design and development of sensors.

We report the cyclic single-crystal-to-single-crystal transformation of three hydrogen-bonded organic frameworks (HOFs), induced by the change of temperature and humidity, which clearly reveals that the -SO3-and -NH2 groups in UPC-H7 and UPC-H8 facilitate the diffusion of water molecules into their anhydrous structures to form hydrous UPC-H9. Their proton conductivity was studied under different humidity at varying temperature, showing that the proton conductivity is closely related to water molecules entering the crystal structures arising from the hydrogen bonded reorganization in combination with the triaxial single-crystal proton conductivity tests.

Ordered and flexible porous frameworks with solution processability are highly desirable to fabricate continuous and large-scale membranes for the efficient gas separation. Herein, the first microporous hydrogen-bonded organic framework (HOF) membrane has been fabricated by an optimized solution-processing technique. The framework exhibits the superior stability because of the abundant hydrogen bonds and strong π-π interactions. Thanks to the flexible HOF structure, the membrane possesses the unprecedented pressure-responsive H2 /N2 separation performance. Furthermore, the scratched membrane can be healed by the treatment of solvent vapor, achieving the recovery of separation performance.