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

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