Fabrication of silicon nanopillar arrays and application on direct methanol fuel cell

We present a simple method that combines self-assembled nanosphere lithography (SANL) and photo-assisted electrochemical etching (PAECE) to fabricate near-perfect and orderly arranged nanopillar arrays for the direct methanol fuel cells electrode (DMFCs) applications. The nanosphere arrays were fabricated by combining thin photoresist grid structure and ultrasonic vibration coating processes. The fabricated nanopillars are with 1.56 μm in height and 250 nm in diameter showing aspect ratio as high as 6.2. Furthermore, PAECE with applying various voltages to produce nanostructure arrays, resulting in different specific surface area for the electrode fabrication of fuel cell was investigated as well. Comparing with typical planar electrodes, the maximum power density of 58.4 W/cm² for nanopillar electrodes is 6.3 times of that for typical planar electrodes with maximum power density of 9.3 W/cm ². These results indicated that the improved performance of the fuel cell is because of the increased contact surface area between the catalyst and fuel cell by utilizing nanopillar arrays.