Chitosan Incorporated with Titanium (IV) Oxide Membrane for Direct Methanol Fuel Cell Application

Abstract

The direct methanol fuel cell (DMFC), a type of promoted polymer electrolyte membrane fuel cell (PEMFC), has received tremendous attention in the past two decades because of its potential as a promising technology for clean and efficient power generation in the twenty-first century. Over the past four decades, the dominancy of perfluorinated proton exchange membranes (PEM) such as Nafion is prolonging in the current PEM technology due to its chemical stability, high proton conductivity and high mechanical strength in the low operating temperatures. However, the Nafion membrane also has several weaknesses, such as high methanol permeability, high manufacturing cost, and dehydration with low proton conductivity at elevated temperatures > 100°C. This study fabricated a novel composite membrane by blending the pristine chitosan (CS) and titanium oxide (TiO₂) at various loadings, 0.5, 1.0, 1.5 and 2.0 wt% to obtain high performance in DMFC. SEM and FTIR analysis showed that the grafting of (O-Ti-O) successfully incorporated into the CS polymer matrix. Water and methanol uptake of CS/TiO₂ composite membrane decreased with increase of TiO₂ loadings, but proton conductivity value increased. The CS/TiO₂ membrane with 1.5wt.%TiO₂ loading exhibited highest proton conductivity (0.41mScm^-1) and lowest methanol permeability (17.18E-08cm²/s) characteristics among other membranes this due to the hydrophilic TiO₂ raised the membrane hydrophilic character by increasing the number of hydrophilic sites, such as OH-, COO- and O-. The results obtained from the study can be used to conclude that chitosan membrane with TiO₂ filler is a promising high performance PEM candidate for DMFC applications.