Triply periodic minimal surfaces as catalyst carriers of compact reformers for hydrogen production and storage systems: recent advances and future perspectives

The pursuit of compact, efficient, and high-performance reformers is crucial for advancing hydrogen production and storage technologies, particularly for on-board applications and thermochemical exhaust heat recuperation. Triply Periodic Minimal Surfaces (TPMS) have emerged as a novel class of lattice structures offering exceptional properties for process intensification. This comprehensive review systematically examines recent advances and future potential of TPMS-based structures as compact reformers for endothermic processes including steam methane reforming, methanol steam reforming, and ammonia decomposition. Analysis reveals that TPMS-based reformers achieve thermal efficiency improvements of 9.5%–35.4% over conventional designs. Key findings include: (i) ammonia conversion of 75% at 450 ∘ C using Ru-catalyzed Gyroid structures; (ii) Nusselt numbers 63%–96% higher than straight-tube configurations; (iii) pressure drop reductions of 50%–90% compared to packed beds; and (iv) hydrogen production rates of 5000 mL/min in optimized micro-reactors. Despite this potential, industrial implementation faces significant hurdles: (a) manufacturing complexities in additive manufacturing, powder removal, and quality assurance; (b) coating challenges due to thermal expansion mismatches between metallic substrates ( 15 -- 20 × 10 − 6 K −1 ) and ceramic catalysts ( 5 -- 10 × 10 − 6 K −1 ); (c) computational limitations in multi-physics simulation; and (d) fabrication costs 10–100 times higher than conventional methods. Future research priorities include: developing scalable coating methods for complex geometries; establishing long-term durability under realistic operating conditions; creating reduced-order models for rapid design optimization; and demonstrating TPMS reformers in target applications including on-board hydrogen production and exhaust heat recovery systems. Addressing these challenges will position TPMS structures as transformative platform technology for next-generation compact chemical reformers essential to the hydrogen economy.