A Microreactor for Hydrogen Production in Micro Fuel Cell Applications

TLDR

The authors propose a silicon‑chip microreactor coupled to a micro fuel cell as a continuous, methanol‑powered alternative to conventional portable batteries. The microreactor is fabricated on silicon using photolithography and deep‑reactive ion etching to create catalyst‑packed parallel microchannels (200–400 µm deep) with a downstream catalyst particle filter, enabling methanol reforming for hydrogen generation. Experimental tests show the microreactor achieves 85–90 % methanol‑to‑hydrogen conversion at flow rates sufficient for an 8–10 W fuel cell, offering higher energy density and eliminating the need for battery recharging cycles.

Abstract

A silicon-chip based microreactor has been successfully fabricated and tested for carrying out the reaction of methanol reforming for microscale hydrogen production. The developed microreactor in combination with a micro fuel cell is proposed as an alternative to conventional portable sources of electricity such as batteries due to its ability to provide an uninterrupted supply of electricity as long as a supply of methanol and water can be provided. The microreformer-fuel cell combination has the advantage of not requiring the tedious recharging cycles needed by conventional rechargeable lithium-ion batteries. It also offers significantly higher energy storage densities, which translates into less frequent "recharging" through the refilling of methanol fuel. The microreactor consists of a network of catalyst-packed parallel microchannels of depths ranging from 200 to 400 /spl mu/m with a catalyst particle filter near the outlet fabricated using photolithography and deep-reactive ion etching (DRIE) on a silicon substrate. Issues related to microchannel and filter capping, on-chip heating and temperature sensing, introduction and trapping of catalyst particles in the microchannels, flow distribution, microfluidic interfacing, and thermal insulation have been addressed. Experimental runs have demonstrated a methanol to hydrogen molar conversion of at least 85% to 90% at flow rates enough to supply hydrogen to an 8- to 10-W fuel cell.