The exploration of novel systems for the electrochemical CO2 reduction reaction (CO2RR) for the production of hydrocarbons like CH4 remains a giant challenge. Well‐designed electrocatalysts with advantages like proton generation/transferring and intermediate‐fixating for efficient CO2RR are much preferred yet largely unexplored. In this work, a kind of Cu‐porphyrin‐based large‐scale (≈1.5 μm) and ultrathin nanosheet (≈5 nm) has been successfully applied in electrochemical CO2RR. It exhibits a superior FECH4 of 70 % with a high current density (−183.0 mA cm−2) at −1.6 V under rarely reported neutral conditions and maintains FECH4 >51 % over a wide potential range (−1.5 to −1.7 V) in a flow cell. The high performance can be attributed to the construction of numerous hydrogen‐bonding networks through the integration of diaminotriazine with Cu‐porphyrin, which is beneficial for proton migration and intermediate stabilization, as supported by DFT calculations. This work paves a new way in exploring hydrogen‐bonding‐based materials as efficient CO2RR catalysts.

The sluggish kinetics and unclear mechanism have significantly hindered the development of Li-CO2 batteries. Here, a Li-CO2 battery cathode catalyst based on a porphyrin-based covalent organic framework (TTCOF-Mn) with single metal sites is reported to reveal intrinsic catalytic sites of aprotic CO2 conversion from the molecular level. The battery with TTCOF-Mn exhibits a low overpotential of 1.07 V at 100 mA/g as well as excellent stability at 300 mA/g, which is one of the best Li-CO2 battery cathode catalysts to date. The unique features of TTCOF-Mn including uniform single-Mn­(II)-sites, fast Li+ transfer pathways, and high electron transfer efficiency contribute to effective CO2 reduction and Li2CO3 decomposition in the Li-CO2 system. Density functional theory calculations reveal that different metalloporphyrin sites lead to different reaction pathways. The single-Mn­(II) sites in TTCOF-Mn can activate CO2 and achieve an efficient four-electron CO2 conversion pathway. It is the first example to reveal the catalytic active sites and clear reaction pathways in aprotic Li-CO2 batteries.

Multidimensional fabrication of metal-organic frameworks (MOFs) into multilevel channel integrated devices are in high demanded for Li-S separators.S uchs eparators have advantages in pore-engineering that might fulfill requirements such as intercepting the diffusing polysulfides and improving the Li + /electrolyte transfer in Li-S batteries.H owever,most reported works focus on the roles of MOFs as ionic sieves for polysulfides while offering limited investigation on the tuning of Li + transfer across the separators.Ap hotoinduced heat-assisted processing strategy is proposed to fabricate MOFs into multidimensional devices (e.g., hollow/ Janus fibers,d ouble-or triple-layer membranes). Fort he first time,at riple-layer separator with stepped-channels has been designed and demonstrated as ap owerful separator with outstanding specific capacity (1365.0 mAh g À1 )a nd cycling performance (0.03 %fading per cycle from 100 th to 700 th cycle), which is superior to single/double-layer and commercial separators.T he findings may expedite the development of MOF-based membranes and extend the scope of MOFs in energy-storage technologies.