Heterogeneous single-walled carbon nanotube catalyst discovery and optimization

High-throughput methods are utilized in the discovery and optimization of heterogeneous catalyst formulations that promote single-walled carbon nanotube (SWNT) synthesis. Catalyst compositions, substrates, and reaction conditions are varied to efficiently investigate SWNT growth by chemical vapor deposition (CVD). A robotic microarray printer is employed to print libraries of the liquid-based catalyst precursors onto various substrates. After CVD, the catalyst arrays are qualitatively screened for yield via electron microscopy. More comprehensive characterization of candidate catalysts is further investigated with confocal Raman spectroscopy (CRS). Detailed CRS mapping reveals information concerning the printed catalyst and nanotube homogeneity in the microarrays. This powerful characterization approach allows for the high-throughput screening of nanotube type, diameter distribution, and purity within the microarrays. The methodology described has enabled the efficient exploration of synthesis parameters, which has led to the identification of SWNT catalysts with various activities.