Enhanced CO₂ Hydrate Formation via Triply Periodic Minimal Surface (TPMS) Structures

This study focuses on innovating carbon capture, utilization, and storage (CCUS) technologies by exploring the combined effect of nature-inspired triply periodic minimal surface (TPMS) architected macroporous structures and hydrate-based methods to enhance CO₂ capture efficiency. In this study, three plastic balls with TPMS structures, the Diamond (D-) type, the Gyroid (G-) type, and the IWP (Isotropic Woodpile, I-) type, were designed using implicit functions and fabricated via 3D printing. And a solid ball with the same diameter was used as the reference group. CO₂ hydrate formation promoted by these three TPMS balls was investigated in a visual dual-chamber reactor system at a temperature of 1 °C (274.15 K) and a pressure of 4 MPa. A real-time imaging system was used to monitor hydrate nucleation and growth and to compare the differences of the induction time of nucleation, the gas consumption, and the morphological evolution. The results demonstrated that all these three TPMS structures significantly enhanced the CO₂ hydrate formation rate and production. The I-type structure exhibited the shortest average induction time (74.8 min), determined through temperature monitoring, representing a 54.8% reduction compared to the reference group. And the average induction time followed the I-type (74.8 min) < the G-type (95.8 min) < the D-type (114 min). The I-type achieved a 33.48% increment of gas consumption in CO₂ uptake compared to the reference group, outperforming the D-type (10.08%) and the G-type (25.27%). It can be explained that the hierarchical porosity of the I-type structure enhanced the gas–liquid interfacial contact and stabilized hydrate precursors, demonstrating its superiority in accelerating nucleation and optimizing mass transfer.