Development of an in situ chemical vapor deposition method for an alumina catalyst bed in a suspended membrane micro fuel reformer

The microfuel reformer with a suspended membrane structure can realize excellent thermal isolation of the reaction area on the suspended membrane because heat conduction through the thin suspended membrane is quite small. However, it is difficult to form an effective catalyst selectively on the suspended membrane. The solution can be given by an in situ chemical vapor deposition (CVD) method by which alumina is deposited from an alumina precursor selectively on the suspended membrane heated by integrated micro-heaters. The deposits were evaluated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX). Self-sustaining hydrogen combustion was demonstrated on the deposited alumina catalyst bed with platinum. The heated area was localized just on the membrane, and temperature difference between the membrane and the bulk substrate reached 570 K, when the temperature of the membrane was 670 °C. The maximum space velocity (SV) value allowable for the formed catalyst was approximately 680 000 h^-1.