Composition and Morphology Engineering of Copper and Tungsten Oxides Deposited on Nickel Foam: A Self-Supported Electrode for Efficient Non-enzymatic Glucose Sensing

Abstract Recent advancements in non-enzymatic glucose sensors have focused on nanostructured transition metal oxides due to their high sensitivity, excellent selectivity, low detection limits, and wide availability. However, challenges such as achieving consistent performance and cost-effective fabrication remain. This study introduces a simple, controllable, and economical method for depositing copper (Cu) and tungsten (W) oxides onto nickel foam at varying Cu:W molar ratios. The electrode's morphology, structure, and electrocatalytic activity, contingent upon the Cu:W molar ratio, were thoroughly examined via comprehensive characterizations, revealing that a Cu:W molar ratio of 1:1 (CuWO4/Ni) exhibited outstanding glucose-sensing performance. It achieved exceptionally high sensitivity of 14240 and 5780 μA mM-1cm-2 within linear ranges of 10-100 and 100-1000 μM, respectively. The sensor also demonstrated a low detection limit of 1.3 μM, a swift response time of 6 s, excellent selectivity, and prolonged stability. These superior attributes are ascribed to the synergistic interactions between Cu²⁺ and WO₄²⁻ centers, combined with the porous microsphere morphology and the conductive 3D nickel foam framework, which together enhance redox reactions, optimized electronic state, active site exposure, and reactants diffusion. This work underscores the potential of CuWO4-based electrode for practical glucose-sensing applications, paving the way for cost-effective and scalable non-enzymatic glucose sensors.