Advanced Carbon-Based Catalytic Materials for the Hydrogen Economy: From Production and Storage to Conversion

The transition toward a sustainable hydrogen economy demands cost-effective, durable, and highly active catalysts that span the entire H2 value chain from green production through storage and transport to end-use conversion. Carbon-based catalytic materials have emerged as a uniquely versatile platform, offering tunable electronic structure, abundant defect- and edge-derived active sites, hierarchical porosity, chemical robustness, and compatibility with both metal-free and single-atom architectures. This review provides a comprehensive overview of advanced carbon-based catalysts designed for the hydrogen economy. We begin with the fundamentals of heteroatom doping, defect and curvature engineering, and M–N4/M–N3 coordination environments that govern binding of hydrogen-relevant intermediates (ΔG_H*, ΔG_OH*, ΔG_O*). Three application pillars are then systematically examined: (i) hydrogen production through HER and OER across PEMWE, AEMWE, AWE, and SOEC platforms, including emerging seawater and biomass-/waste-coupled electrolysis; (ii) hydrogen storage and chemical carriers, encompassing physisorption on porous carbons and catalytic (de)hydrogenation of liquid organic hydrogen carriers, ammonia, and formic acid; and (iii) hydrogen utilization in PEMFCs, AEMFCs, direct liquid fuel cells, and hydrogen-coupled CO₂ and N₂ reduction. Particular emphasis is placed on structure–activity descriptors, operando mechanistic probes, device-level benchmarking from rotating-disk electrodes to membrane-electrode assemblies, and techno-economic considerations including the levelized cost of hydrogen. We conclude by highlighting critical challenges — carbon corrosion, PGM-free durability, and scalable synthesis — and outline future directions that integrate AI-accelerated discovery, atomic-precision synthesis, and biomass-derived circular-economy carbons for next-generation hydrogen technologies.