Methanol is a volatile fuel which can be fed into microfluidic fuel cells in vaporized form. However, the methanol oxidation reaction is relatively sluggish compared with the hydrogen oxidation reaction. Therefore, a novel dual fuel microfluidic fuel cell system powered by both methanol and methanol-derived hydrogen via photocatalysis is developed, which can achieve much improved cell performance while eliminating the hydrogen transportation, storage and safety issues. Pt/P25 is adopted as the photocatalyst which photo-reforms the methanol to hydrogen in the fuel tank. The intermediate during the photoreforming process can also be fed into the microfluidic fuel cell as a fuel. Different cell performance can be achieved by varying the fuel-water mix ratios in the tank. By optimizing the ratio, the peak power density can be increased by more than 10 times when the system is exposed to simulated solar light (3 suns) illumination.