Global solid waste management and construction material sustainability converge in fly ash (FA), with approximately 1700 million tons generated annually, while current utilization fails to adequately address its environmental burdens. This work establishes an ecomaterials paradigm by synthesizing controllable-sized carbon nanomaterials in situ on FA, converting FA into high-performance cement reinforcement materials. Through chemical vapor deposition, planar graphene is grown via intrinsic oxide catalysis and tubular carbon nanotubes on iron-functionalized FA, creating catalyst-integrated composites that eliminate purification steps and dispersion challenges. The substrate-bonded nanomaterials drastically reduce production costs compared to commercial alternatives while ensuring optimal distribution in cementitious systems. These solid waste-derived ecomaterials function as multifunctional additives at dosages of 5%–20%, reducing dependence on virgin cement while delivering complementary performance enhancements: graphene provides exceptional early-age enhancement (+36.96% flexural strength at 3 d in mortar, +18.55% compressive strength at 7 d in concrete), whereas carbon nanotubes provide sustained reinforcement maintaining advantages through 28 d across both mortar and concrete systems. This catalyst-integrated approach simultaneously addresses solid waste accumulation, reduces cement-related emissions, and delivers superior material performance compared to conventional alternatives, demonstrating a scalable pathway for solid waste valorization through dimensional engineering of carbon nanomaterials.

The conversion of waste tire pyrolysis oil (WTPO) into S-doped porous carbon nanorods (labeled as WPCNs) with hierarchical pore structure is realized by a simple template-directed approach. The specific surface area of as-obtained porous carbon nanorods can reach up to 1448 m² g⁻¹ without the addition of any activating agent. As the capacitive electrode, WPCNs possess the extraordinary compatibility to capacitance, different electrolyte systems as well as long-term cycle life even at a commercial-level areal mass loading (10 mg cm⁻²). Besides, only an extremely small capacitance fluctuation is observed under the extreme circumstance (−40 to 80 °C), reflecting the excellent high- and low-temperature performance. The relationship between the pore structure and capacitive behavior is analyzed by comparing WPCNs with mesopores-dominated asphalt-derived porous carbon nanorods (APCNs) and micropores-dominated activated carbon. The molecular dynamics simulation further reveals the ion diffusion and transfer ability of the as-prepared carbon materials under different pore size distribution. The total ion flow (N_T) of WPCNs calculated by the simulation is obviously larger than APCNs and the N_T ratio between them is similar with the experimental average capacitance ratio. Furthermore, this work also provides a valuable strategy to prepare the electrode material with high capacitive energy storage ability through the high value-added utilization of WTPO.