Curvature-engineered carbon supports dramatically boost electrocatalytic activity of Ni single atoms for glucose...

Although the local microenvironment exerts a profound influence on the catalytic activity of single-atom nanozymes, the role of support curvature has remained poorly understood. Herein, we construct a high-curvature onion-like carbon support via a template-free process, in which Ni nanoparticles act simultaneously as metal source, hard template, and carbon reconstructing agent. This curved architecture not only anchors Ni single atoms but also modulates their electronic structure, as confirmed by HAADF-STEM, X-ray absorption fine structure, and TEM, which reveal isolated bright spots, Ni-N coordination, and hollow curved shells, respectively. Experimental and theoretical analyses reveal that the curvature reduces the Ni valence state and upshifts the d-band center, thereby optimizing glucose adsorption and accelerating dehydrogenation kinetics. The curved support substantially enhances the catalytic activity of Ni single atoms toward glucose oxidation compared with planar carbon, achieving a sensitivity of 1739.43 μA mM^-1·cm^-2, a detection limit of 0.6 μM, and excellent selectivity. Overall, our findings establish a clear structure-activity relationship and highlight curvature engineering as a powerful strategy for designing highly sensitive electrochemical sensors, opening new possibilities for microenvironmental tuning in practical bioanalysis.