Tailoring Cadmium Composition on Titanium Dioxide to Achieve Enhanced Photocatalytic Glucose Fuel Cell Anode Performance

Abstract

In this study, titanium dioxide (TiO2)-supported Cd catalysts were prepared at 0.05–3% of Cd loading by employing the incipient wetness impregnation method. These catalysts were characterized via X-ray diffraction (XRD), scanning electron microscopy–energy-dispersive X-ray (SEM–EDX), high-angle annular dark-field scanning transmission electron microscopy and TEM–EDS mapping, inductively coupled plasma–mass spectrometry (ICP–MS), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO), and temperature-programmed desorption (TPD). XRD and TEM analysis showed that TiO2 exhibited an anatase structure. SEM–EDX and mapping, XPS, TPR, TPO, and TPD analysis revealed that the Cd addition to TiO2 altered the electronic structure and surface properties of TiO2. Photocatalytic electro-oxidation measurements were conducted to define the glucose electro-oxidation activity, stability, and resistance of catalysts with cyclic voltammetry, chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) in 1 M KOH + 0.5 M glucose solution at 100 mV/s in the dark and under UV illumination. 0.1% Cd/TiO2 catalyst showed the best photocatalytic glucose electro-oxidation activity with a 6 mA/cm2 specific activity compared to the dark (0.89 mA/cm2). CA and EIS measurements indicated that 0.1% Cd/TiO2 catalyst exhibited the highest stability and the lowest resistance. In conclusion, Cd-doped TiO2 is a promising catalyst for photocatalytic fuel cells.