A Pd/Al2O3-based micro-reformer unit fully integrated in silicon technology for H-rich gas production

TL;DR

This paper presents a fully integrated silicon-based micro-reformer unit utilizing Pd/Al2O3 catalysts for efficient hydrogen-rich gas production, optimized for portable fuel cell applications.

Contribution

It introduces a novel micro-reformer design with optimized geometry, integrated heating, and catalyst coating, compatible with microelectronics fabrication for cost-effective hydrogen generation.

Findings

Optimized micro-channel design improves gas flow and efficiency.

Pd/Al2O3 catalyst effectively converts DME to hydrogen.

Integrated heater ensures uniform temperature control.

Abstract

This work reports the design, manufacturing and catalytic activity characterization of a micro-reformer for hydrogen-rich gas generation integrated in portable-solid oxide fuel cells (u-SOFCs). The reformer has been designed as a silicon micro monolithic substrate compatible with the mainstream microelectronics fabrication technologies ensuring a cost-effective high reproducibility and reliability. Design and geometry of the system have been optimized comparing with the previous design, consisting in an array of more than 7x103 vertical through-silicon micro channels perfectly aligned (50 {um diameter) and a 5 W integrated serpentine heater consisting of three stacked metallic layers (TiW, W and Au) for perfect adhesion and passivation. Traditional fuels for SOFCs, such as ethanol or methanol, have been replaced by dimethyl ether (DME) and the chosen catalyst for DME conversion consists of Pd nanoparticles grafted on an alumina active support. The micro-channels have been coated by atomic layer deposition (ALD) with amorphous Al2O3 and the influence of rapid thermal processing (RTP) on such film has been studied. A customized ceramic 3D-printed holder has been designed to measure the specific hydrogen production rates, DME conversion and selectivity profiles of such catalyst at different temperatures.