D.N. McIlroy, G. Corti, T. Cantrell, M. Beaux, T. Prakash, M.G. Norton
Since catalytic performance is a limiting factor for many essential elements of the hydrogen economy, the need for improved catalysts is great. One-dimensional (1D) nanomaterials are ideal catalysts because of their large surface area to volume ratio, which results in orders of magnitude more reactive sites than thin films or bulk materials. An important reaction for hydrogen generation is the water-gas shift reaction where carbon monoxide is reformed with water. Preliminary results show that mats of GaN nanowires decorated with Au nanoparticles can catalyze this reaction at room temperature. In addition to precious metal-based catalysts, several 1D ceramic nanostructures including TiO2 and MnO2 have shown promise as catalysts for hydrogen generation. Yet huge opportunities remain for the development of low temperature, inexpensive, efficient catalysts. The most promising materials will be compatible with high-volume manufacturability, which is required for economical catalyst production. We have developed a low cost process to produce very large area mats of silica nanosprings that provide a stable catalyst support. The nanosprings can be functionalized by the application of nanocrystalline oxides (e.g., ZnO, TiO2, CuO) and/or metal nanoparticles (e.g., Au, Pt, Pd). This process creates hierarchical nanostructures engineered for specific catalyst applications.