Interface Engineering p-n Heterostructured Core-Shell Mesoporous Particles for Cascade Catalysis Promoted Gas Sensing

Cells have greatly inspired advancements in chemical processes, including leveraging the idea of cascade catalysis to drive thermodynamically unfavorable reactions and mimicking the compartmentalized architecture to design novel nanostructures. Here, a single-particle cascade catalysis promoted gas sensing platform is inspired to be designed (denoted as CoSnO₃@mCeO₂) by positionally assembling n-type mesoporous CeO₂ catalytic shell on p-type CoSnO₃ gas sensitive core. Uniform CoSn(OH)₆@mCe(OH)_x core-shell particles with tailored mesostructures, tunable large mesopores, and adjustable shell thicknesses are first constructed. After thermal treatment, CoSnO₃@mCeO₂ particles are obtained, which serve as cascade catalysis enhanced sensitive layer for fabricating gas sensors with independent catalytic and sensing control. As a proof-of-concept, the CoSnO₃@mCeO₂ gas sensors exhibit nearly three times higher acetone sensitivity (R_g/R_a = 26.81-50 ppm) than individual CoSnO₃ sensors with an ultralow limit of detection of 5.22 ppb. The enhanced sensitivity is achieved through a tandem catalytic reforming-oxidation sensing procedure, which begins with the primary catalytic reforming of acetone to acetic acid in the mCeO₂ shell, followed by the secondary sensing reaction of acetic acid in the CoSnO₃ core. The design concept of cascade catalysis promotes gas sensor can serve as a paradigm for developing single-particle functional nanodevices for various applications.