Freestanding laser-induced graphene/carbon fiber frameworks functionalized with NiO for high-performance non-enzymatic glucose sensing

Abstract

Non-enzymatic electrochemical glucose sensors (NEGS) offer advantages over their enzymatic counterparts, but their conventional supporting scaffolds suffer from poor conductivity, limited surface area, and binder dependence. Herein, we present a strategy to fabricate a high-performance, binder-free NEGS on a hierarchical laser-induced graphene/carbon fiber framework (LW-CFF-B) functionalized with NiO nanoparticles. The 3D porous LW-CFF scaffold was engineered by carbon fiber felt (CFF) enhanced LIG using 1,4-phenylenediboronic acid (PA)-modified liquid benzoxazine (PGE-a) as the precursor. PA plays a dual role in enhancing the char yield and improving electrical conductivity (sheet resistance was reduced from 2.54 to 1.23 Ω sq⁻¹). Moreover, PA promotes the formation of a hierarchical porous carbon architecture, which is beneficial for facilitating the electrochemical performance of the obtained carbon product. The subsequent laser-assisted deposition of a NiO nano-layer on the LW-CFF-B scaffold yielded the LW-CFF-B-Ni electrode. This optimized architecture combines mechanical integrity with exceptional electrocatalytic properties, leading to outstanding glucose sensing performance as follows: ultrafast response (1.2 s), ultrahigh sensitivity (5758 µA mM⁻¹ cm⁻²), low detection limit (0.16 µM), and excellent selectivity against common interferents. The developed sensor demonstrated appreciable recoveries (91.1% to 107.3%) regarding glucose concentration in beverages. These outstanding analytical results demonstrate the significant potential of this sensor in precise glucose monitoring.