Probing hydrogen in ZnO nanorods using solid-state H1 nuclear magnetic resonance

A low-temperature reflux method was developed to synthesize large quantities of well-dispersed freestanding ZnO nanorods, which enabled the direct observation and characterization of hydrogen by solid-state H1 magic angle spinning nuclear magnetic resonance (NMR) spectroscopy. In contrast to nano/micrometer particles of ZnO, a surprisingly sharp H1 NMR resonance was maintained in ZnO nanorods that were heated to 500°C, suggesting the existence of unusually stable hydrogen. Quantitative H1 NMR measurements indicate that about 0.1% on a molar basis of these hydrogen species resides in the lattice of ZnO nanorods. This work has demonstrated that H1 NMR is a powerful technique for probing hydrogen in ZnO nanorods.