Salicylate‐Assisted Surfactant‐Directed Assembly Synthesis of Uniform Mesoporous ZnO Nanospheres for Gas Sensing Applications

Mesoporous zinc‐based nanomaterials exhibit considerable potential across a spectrum of applications, yet their controlled synthesis remains challenging due to the rapid hydrolysis and condensation kinetics of Zn 2+ ions. Herein, we report a facile surfactant‐directed synthesis strategy for the controllable synthesis of monodisperse mesoporous Zn(OH) 2 nanospheres and they can be readily converted into semiconducting mesoporous ZnO (denoted mZnO) nanospheres via calcination. In this synthesis, by employing sodium salicylate (NaSal) as a multifunctional modulator, we regulate micelle organization and zinc precursor diffusion, overcoming the inherent kinetic limitations of Zn 2+ . The resulting crystalline mZnO can serve as an ideal host for loading ultrasmall Pt nanoclusters to produce Pt/mZnO composite nanospheres with abundant metal–metal oxide interfaces. Using Pt/mZnO nanospheres as the sensitive materials, gas sensors were fabricated on micro‐electromechanical systems (MEMS) devices, which display an exceptional performance in the detection of low‐concentration acetone vapor. The gas sensor exhibited high response (4.9 toward 1 ppm acetone), low detection limit (170 ppb), excellent selectivity, and good long‐term stability. In situ spectroscopy characterization results reveal that, during the gas‐sensing process, the reaction pathway involves catalytic oxidation of acetone over Pt/mZnO nanospheres via intermediate carboxylates. This work offers a generalized approach for designing functional mesoporous metal oxides with enhanced interfacial activity for advanced sensing and catalytic applications.