Accurate identification of carbon‐based metal‐free electrocatalyst (CMFE) activity and enhancing their catalytic efficiency for O2 conversion is an urgent and challenging task. This study reports a promising strategy to simultaneously develop a series of covalent organic frameworks (COFs) with well‐defined heterocyclic‐free biphenyl or fluorenyl units. Unlike heteroatom doping, the developed method not only supplies methyl‐induced molecular configuration to promote activity, but also provides a direct opportunity to identify heteroatom‐free carbon active centers. The introduction of methyl groups (MGs) with reversible valence bonds into a pristine biphenyl‐based COF results in an excellent performance with a half‐wave potential of 0.74 V versus the reversible hydrogen electrode (RHE), which is among the highest values for CMFE‐COFs as oxygen reduction reaction (ORR) electrocatalysts. Combined with in situ Raman spectra and theoretical calculations, the MG‐bound skeleton (DAF‐COF) is found to produce ortho activation, confirming the ortho carbon (site‐5) adjacent to MGs as active centers. This may be attributed to the opening and binding of MGs, which effectively regulate the molecular configuration and charge redistribution, as well as improve charge transfer and reduce the energy barrier. This study provides insight into the design of highly efficient metal‐free organic electrocatalysts via the regulation of valence bonds.

carbon materials are catalytically inefficient, they can be promoted by heteroatom doping, especially nitrogen (N) atoms. For example, Dai and co-workers introduced the electron-donating N atoms into the sp 2 carbon nanotube through chemical doping, its electronegativity can induce charge redistribution of carbon (C) atoms in the skeleton of carbon nanotubes, and change the electronic structure of the surrounding C atoms, thus facilitating the improvement of catalytic performance and even higher than those of Pt-based catalysts in alkaline medium. [3] Huang et al. prepared pyridinic-N dominated graphene-like nanocarbon materials with high electrocatalytic activity by in situ alkaline activations of cellulose and ammonia injection methods. [4] Qu and co-workers synthesized N-atom doped graphene quantum dots by chemical vapor deposition methods, providing an efficient approach to designing efficient ORR electrocatalysts. [5] Such a heteroatom doping strategy has been regarded as a significant method to enhance ORR performance. In order to deeply modulate the definite skeleton, doping degree, and content of catalytic sites, [6] new metalfree catalytic systems with controllable electron environment of active centers at the molecular scale should be developed through organic heterocyclic strategy.Conjugated microporous polymers (CMPs) are a distinctive class of multifunctional porous materials that combine extended π-conjugated structures and permanent nanopores. With the advantages of adjustable molecular structure and high chemical stability, CMPs have emerged as new electrode materials for ORR catalysis. [7] Compared with conventional building blocks in CMP skeletons, electron-deficient units, especially, alkynyl groups with the advantage of convertible hybrid orbital, small steric hindrance, increased overlapping electron clouds, and high-density activity can modulate the electronic state of organic molecules and promote the adsorption of oxygen intermediates, [8] thus optimizing electrocatalytic activity and improving ORR performance. However, due to the rigid molecular skeleton of alkynyl-containing CMPs, they always exhibit low conductivity and crystallinity, as well as intrinsic trap-site density, leading to poor ORR catalytic activity. [9] Therefore, it is important to develop CMP-based heterostructureThe oxygen reduction reaction (ORR) is a key process in green energy conversion technology. Heteroatom doping has been proven to be a prospective strategy to prepare metal-free carbon-based electrocatalysts, but such methods often suffer from uncontrollable catalyst frameworks and imprecise active sites. Herein, an organic heterocyclic strategy is adopted to modulate the charge redistribution of alkynyl-containing conjugated microporous polymers (CMPs) by introducing varied five-membered heterocyclic structures. Among these CMPs, the S, 2N-containing thiadiazole heterocyclic molecule (CMP-Tdz) with carbonized alginate materials (C CA ) displays a remarkable quasi-four-electron-transfer ORR pathway, exhibiting...

Exploring highly‐efficient palladium (Pd)‐based electrocatalysts for the alcohol oxidation reaction (AOR) is crucial yet challenging for chemists due to the vague Pd interface with an uncontrollable electronic environment. Herein, an organic heterocyclic strategy is used for the first time to modulate the electronic state of Pd electrocatalysts by anchoring Pd nanoparticles to conjugated microporous polymers (CMPs) with varied S‐, N‐, O‐, or S, N‐heterocycles. Among these CMPs, the S, N‐containing thiazole heterocyclic polymer SNC with Pd catalyst exhibits highly‐efficient current densities of 1575.0 mA mgPd−1 for methanol oxidation and 1071.0 mA mgPd−1 for ethanol oxidation, which are among the highest performance in the heterocyclic modulated Pd systems and surpass the commercial Pd black catalyst. Detailed theory calculations suggest that although the furan (O‐heterocycle) polymer OC has the strongest charge transfer (0.057 |e|) with the Pd cluster, the moderate electron transfer (0.041 |e|) of the Pd/SNC heterojunction with an S···N···Pd noncovalent interaction shows the best catalytic reaction kinetics. Moreover, the d‐band of the Pd/SNC system is closer to the volcano vertex than its counterparts. These results indicate that appropriate electron transfer intensity regulation of Pd electronic state by well‐defined heterocyclic structures may significantly improve AOR activity.

Conjugated organic molecular heterostructures have been widely investigated as an alternative for photocatalytic hydrogen evolution reaction (HER). The controllable replacement of pure carbon rings with heterocyclic units can significantly change...