Glucose electrooxidation modelling studies on carbon nanotube supported Pd catalyst with response surface methodology and density functional theory

Abstract

In this study, carbon nanotube supported Pd catalysts (Pd/CNT) are synthesized at different weight percentages by the sodium borohydride (NaBH4) reduction method to investigate catalytic performance of glucose electrooxidation reaction. 0.5% Pd/CNT, 3% Pd/CNT, and 7% Pd/CNT catalysts are characterized by using X-ray diffraction (XRD), electron microscopy with energy dispersive X-ray (SEM-EDX), and N2 adsorption-desorption measurements. The average particle size and surface area of 3% Pd/CNT catalyst are determined as 46.33 nm and 129.48 m2/g, respectively. Characterization results indicate that Pd/CNT catalysts are successfully prepared by NaBH4 reduction method. Cyclic voltammetry measurements are performed to investigate the effect of Pd loading for the glucose electrooxidation. CV results reveal that 3% Pd/CNT catalyst exhibits best glucose electrooxidation activity. Following this, experimental optimization is performed to obtain maximum glucose electrooxidation activity via response surface methodology (RSM). Estimated and experimental specific activities at optimum experimental conditions are assigned as 6.186 and 5.832 mA/cm2, respectively. To understand the glucose electrooxidation activity on the surface of Pd/CNT, surface modeling is also performed with density functional theory (DFT) method to investigate adsorption of glucose molecule on CNT supported Pd surface. The DFT results emphasize that the addition of Pd atom to the CNT structure significantly improves the catalytic performance in glucose electrooxidation.