Guest Molecule Diffusion-Regulated Morphological Evolution of Gas Hydrate Crystals

The precise regulation of crystal morphology for targeted application scenarios continues to pose a formidable challenge, as exemplified by gas hydrates with immiscible precursors. Here, using sodium dodecyl sulfate solutions to suppress film-like growth at gas-liquid interfaces and presettled microcrystals as seeds, we realized hydrate growth in aqueous environments and flexibly controlled its morphology ranging from polyhedral to finally dendritic forms, with hopper-shaped form observed for the first time. Combining X-ray computed tomography scanning for precise quantification of growth kinetics and theoretical modeling, we further unveiled that hydrate growth follows a mass-transfer-dominated mechanism irrespective of crystal morphology. The accelerated growth kinetics induced by elevated supersaturation promote the morphological transition toward hopper or dendritic forms, which effectively amplifies specific surface area to accommodate intensified mass transfer requirements. The coupling of interfacial transport control with seeded nucleation furnishes a general platform for shape engineering in host-guest solids, thus facilitating hydrate-related applications and inspiring other crystal systems.