Catalytic combustion as a synthesis tool for micropatterned carbon materials

There is an extensive literature on the catalysis of carbon combustion by finely divided metals. Under some conditions a high degree of catalytic enhancement is observed, and the accelerated carbon consumption occurs in the immediate vicinity of the catalyst particle. These observations suggest that catalytic combustion could be used as a tool for shape control or micropattern formation in carbon materials, in which molecular oxygen serves as a “dry” etchant acting selectively on catalyst particles positioned by controlled metal deposition. This study uses carbon thin films and liquid-phase catalyst deposition as a model material and reaction system for a proof-of-principle demonstration of this new concept. A polydimethylsiloxane stamping technique is used to transfer metal chloride solutions onto carbon thin films in the form of ordered droplet microarrays that dry to produce catalytic micropatches. Controlled combustion at 400 °C selectively etches the carbon in the catalyst-doped regions to reveal the underlying quartz substrate in a predefined circle micropattern. This study focuses on catalyst selection, drying behavior, pattern resolution, feature fidelity, and etchant selectivity ratio, and the results are used to discuss the further potential for catalytic combustion synthesis and shape control.