Epoxy Group-tuned Co-N4 Active Sites on Graphyne for High-efficiency Hydrogen Peroxide Production
摘要
The green electrochemical synthesis of hydrogen peroxide (H2O2) through two-electron oxygen reduction reaction (2e− ORR) urgently requires catalysts with high selectivity and stability. Regulating the electronic structure and stable anchoring of molecular catalysts is an effective strategy to achieve this goal. Based on this, this research focuses on the anchoring effect of oxidized graphyne (GYO) on cobalt phthalocyanine (CoPc) and the regulation mechanism of its epoxy group on the electronic structure of active sites, and proposes a novel GYO-CoPc composite catalyst. Through a nitric acid oxidation strategy, the GYO substrate constructs a three-dimensional porous network and abundant epoxy groups. It firmly anchors CoPc through π-π interactions and induces an electron-deficient state at the Co-N4 center via an electron coupling effect. Characterization of morphology and physical phase confirm the precise regulation of the active site by epoxy groups, which significantly weakens the adsorption strength of the *OOH intermediate. Electrochemical tests show that GYO-CoPc achieves a H2O2 selectivity of 99% at 0.65 V vs. RHE, with a high yield of 7.15 mol·g−1·h−1 and a stability of over 30 h. This work reveals new strategy for the design of carbon-based molecular catalysts and provides important references for the development of efficient 2e− ORR catalytic systems.