Speaker
Descrizione
Three-dimensional (3D) graphene foams are extremely lightweight materials that combine a large active surface area, electrical conductivity, and broadband light absorption. These properties make them promising building blocks for next-generation energy systems. Their fabrication, however, remains challenging because it requires both reproducible control over the porous structure and sufficient mechanical stability to prevent the architecture from collapsing when the metallic growth scaffold is removed. In this work, we report a stepwise strategy for fabricating freestanding 3D multilayer graphene foams using nanotextured Ni-Cu templates. Porous Ni films were first deposited on Cu foils by hydrogen-bubble-assisted electrodeposition, which defined the initial architecture of the metallic scaffold. The samples were then pre-annealed at 1000 °C for different durations to promote Cu diffusion into the porous Ni layer and progressively form Ni-Cu alloy templates. Graphene was subsequently grown under identical chemical vapour deposition conditions for all samples, after which the metallic scaffold was removed by wet chemical etching without the use of a polymer support. By varying only the template pre-annealing time while keeping the graphene growth parameters constant, we directly correlated the structural and compositional evolution of the Ni-Cu scaffold with the organization of the graphene coating and the ability of the resulting carbon network to retain its freestanding 3D architecture after etching. The evolution of the Ni-Cu template was found to strongly influence the structural organization of the graphene coating and the stability of the resulting freestanding network. Low-defect graphene was obtained even on non-alloyed templates. However, only scaffolds pre-annealed for at least 3 h produced graphenic shells sufficiently continuous and interconnected to preserve the porous 3D architecture after metal removal. Raman spectroscopy and X-ray diffraction indicated that increasing the pre-annealing time improved the structural organization of the graphene network by reducing residual strain and stacking disorder. These structural improvements were accompanied by progressively lower degradation during the support-free removal of the metallic scaffold. The optimized foams combined a well-preserved 3D morphology with low sheet resistance, negligible optical transmittance, and strong broadband visible-light absorption. This combination highlights the advantages of their interconnected porous architecture, which provides continuous pathways for charge transport while promoting photon trapping within the graphene network. Overall, these results show that controlled Ni-Cu interdiffusion provides an effective means of tuning the structural quality, homogeneity, and mechanical stability of freestanding graphene foams without changing the graphene growth conditions. This template-design strategy offers a versatile foundation for developing next-generation 3D graphene electrodes that combine high surface area, efficient charge transport, and enhanced light management.
| Consenso all'uso dei dati | Acconsento che l'abstract possa essere incluso nel programma del convegno e nel libro degli abstract. Acconsento al trattamento dei dati personali per finalità organizzative del convegno, in conformità al GDPR. |
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| Giovane Ricercatore (under 40) | Yes |
