Hirokazu Ishitobi

Enhanced Catalytic Activity of Pt for Electrooxidation of Ethanol by Using Silica-Carbon Composite as the Catalyst Support

The technical issue of direct ethanol fuel cells is slow kinetics of ethanol electrooxidation by using noble metals such as Pt. We propose silica-embedded carbon nanofiber (SECNF) as a catalyst support for the electrooxidation of ethanol to improve catalytic activity of Pt. SECNF was prepared by electrospinning, then Pt nanoparticles were deposited on SECNF. Catalyst characterizations were performed by SEM, EDX, and XRD. Cyclic voltammetry was performed to analyze catalytic activity of Pt/SECNF. The mass activity of Pt/SECNF was 2.9 times higher than a commercially available Pt/carbon catalyst (Pt/Ccom). Electrochemically active surface area of Pt/SECNF was lower than Pt/Ccom. Hence, the activity enhancement is attributed to the improvement of specific activity for Pt/SECNF. This enhancement is attributed to the interaction between Pt and SiO2 like hydrogen spillover. Pt/SECNF is a promising catalyst for direct ethanol fuel cells which can reduce Pt loading.

Effect of Embedded TiO2 in Carbon Nanofiber Support on Pd Catalyst Activity for Formic Acid Oxidation

Pd supported on TiO2-embedded carbon nanofibers (Pd/TECNF) were prepared as the anode catalyst for direct formic acid fuel cells (DFAFCs) using an electrospinning technique. The effect of the TiO2 content on the catalytic activity of Pd was investigated based on the electrochemical measurements of cyclic voltammetry (CV), chronoamperometry (CA), and also characterization by XRD, EDX, FE-SEM and CO stripping. The activity was significantly increased by an increase in the TiO2 content up to Ti/C=0.44 and then decreased. The maximized activity was improved eight fold by the TiO2 addition. The increased activity was attributed to the increased electrochemically active surface area due to the modified surface of the nanofibers.