Adjacent Se site boosts electrocatalytic activity of Ni single atoms for realizing highly sensitive electrochemical glucose sensing

Metal single-atom materials are attracting tremendous attention in the field of electrochemical sensing. How to regulate the electrocatalytic activity of metal single-atom materials remains a significant challenge. Here, it was the first time that a dual hetero-atom catalyst comprising adjacent Ni N 4 and Se C 3 sites (Ni 1 Se 1 /NC) was designed for boosting electrochemical glucose sensing. Ni 1 Se 1 /NC material was synthesized through via high-temperature pyrolysis. Experimental and theoretical results demonstrate that Ni single atoms function as the primary active sites for glucose activation. Adjacent Se single atoms, while catalytically inactive, modulate the electronic structure of Ni through electron donation from Ni N 4 to Se C 3 sites. This accelerates electron transfer and enhances glucose molecule adsorption. The synergistic effect of the Ni Se atomic pair significantly boosts electrocatalytic glucose oxidation activity, resulting in a nearly 6-fold increase in glucose detection sensitivity. Unlike dual-atom site systems where both atoms serve as catalytic centers, this study reveals the unique function of the Se site as a non-catalytic modulator. Via electronic effects, Se enhances the catalytic activity of Ni sites without directly participating in the reaction, representing a departure from conventional dual-atom site mechanisms.