Co-tuning composition and channel-rich structure of Ag-Pd alloys toward sensitive electrochemical biosensing

Noble-metal nanostructures are promising for biosensing applications owing to their fantastic physicochemical properties, but the rational design of their easy-accessible and reactive surface is still challenging. This work is devoted to the interfacial engineering of Ag-Pd alloys, including tuning alloy composition and geometric structure, to promote the electrochemical biosensing performance. Through a co-tuning tactic with controlled reduction, channel-rich Ag 1 Pd 3 alloys with optimal electronic configurations and accessible active surface are successfully obtained, which afford high sensitivity, outstanding selectivity and excellent repeatability to detect H 2 O 2 and glucose biomarkers. As experimentally and theoretically evidenced, tailoring the composition of Ag-Pd alloys ameliorates electronic configurations due to ligand effects, which can optimize the binding with the key intermediate of OH*, and thereby boost electrochemical kinetic steps on surface. Meanwhile, tuning geometric structure with abundant channels enables fast transport of analytes toward largely-exposed active sites. Providing an atomic-level interpretation of structure-dependent biosensing, this work is anticipated to offer guidelines for the development of efficient sensing platforms.