Strain-regulated catalytic properties of two-dimensional fullerene macromolecular networks

Abstract

Two-dimensional fullerene macromolecular networks are layered architectures formed by covalently linked fullerene clusters of varying sizes. These structures exhibit significant catalytic potential owing to their fully exposed active sites, unique electronic properties, and relatively simple and uniform configurations. In this study, two-dimensional networks composed of fullerene molecules (C20, C24, C36, C60, and C72) were constructed in two symmetric configurations: quasi-tetragonal and quasi-hexagonal phases. First-principles calculations were employed to systematically investigate the structural stability, electronic properties, strain-dependent mechanical behavior, and catalytic performance of these networks. Analyses of binding energy, dynamic stability, and thermal stability at room temperature reveal a consistent stability ranking for both phases, from strongest to weakest: C24, C36, C20, C72, and C60. Electronic structure characterization further shows that qHP C20 and qTP C20 are metallic, qHP C72 is a narrow-bandgap semiconductor, and qHP C36 exhibits a semi-metallic character. In contrast, qTP C72, qTP C60, qHP C60, qTP C36, qTP C24, and qHP C24 are wide-bandgap semiconductors. These diverse electronic properties provide a physical basis for potential applications. In addition, detailed analysis of catalytic properties indicates that both compressive and tensile strains can effectively modulate the hydrogen evolution reaction and oxygen evolution reaction activities of these networks. This tunability is of significant importance for addressing energy-related challenges.