Bimetallic Metal‐Acetylide Frameworks for Highly Selective and Durable H 2 O 2 Electrosynthesis

Abstract

ABSTRACT Metal‐acetylide frameworks (MAFs) feature tunable d–π orbital hybridization between transition metal centers and π‐ conjugated acetylide linkers. Here we report a two‐dimensional (2D) MAF, ZnTTPP‐Ni‐AF, assembled from zinc‐thienylporphyrin units (ZnTTPP) and nickel(II)‐bis(acetylide) linkers (─C≡C─Ni(PBu 3 ) 2 ─C≡C─, Bu = ─CH 2 CH 2 CH 2 CH 3 ), as a selective electrocatalyst for the two‐electron oxygen reduction reaction (2e − ORR) to H 2 O 2 . In alkaline electrolyte, ZnTTPP‐Ni‐AF achieves 94% H 2 O 2 selectivity and >90% Faradaic efficiency (FE) in an H‐cell, with excellent stability over 148 h. In a flow cell, it maintains >91% FE from 20 to 160 mA cm −2 , delivering an H 2 O 2 yield rate of 13.68 mol g −1 h −1 at 160 mA cm −2 . Combined experimental and theoretical studies reveal that synergy between Zn−N 4 porphyrinic centers and Ni II ‐bis(acetylide) motifs promotes O 2 activation and stabilizes the *OOH intermediate, steering the ORR toward the 2e − pathway. Enhanced Ni‐3 and O‐2 p orbital hybridization facilitates proton‐coupled electron transfer to *OOH while suppressing O─O bond cleavage. This work demonstrates that engineering orbital hybridization and bimetallic cooperativity in MAFs provides an effective strategy to overcome the intrinsic activity‐selectivity trade‐off in electrocatalytic H 2 O 2 synthesis.