Organic Heterocyclic Strategy for Precisely Regulating Electronic State of Palladium Interface to Boost Alcohol Oxidation

Abstract

AbstractExploring 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.