Hollow nanostructured materials are widely used in catalysis. Besides the large surface area, well-defined active sites, and delimited cavities, the favorable catalytic performance of hollow nanostructured catalysts can be ascribed to the enrichment of reactant molecules around active species implemented by the hollow chambers. Previous studies found the enrichment of reactant is induced by surface curvature, but understanding of the structural effect still needs quantitative discussion. Herein, we elucidate the curvature effect by building nanotube assembled hollow spheres with controllable morphology. By using experimental and computational methods, we demonstrate that with increased hollow-sphere size, the reactant concentration inside hollow sphere decreases while the diffusion flux increases, both affecting the reaction rate. This balancing effect between adsorption and diffusion induced by surface curvature suggests a unique strategy to design more efficient and selective hollow nanostructured catalysts.

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