Specific Sn–O–Fe Active Sites from Atomically Sn-Doping Porous Fe2O3 for Ultrasensitive NO2 Detection

The heteroatom atomically doping strategy was reported to construct highly efficient sites on metal oxides for the detection of low-concentration gas. The atomically dispersed Sn atoms were intentionally incorporated into the Fe 2 O 3 lattice during the oxidative annealing of Fe-based metal organic framework, leading to specific Sn–O–Fe sites, porous structures, and abundant oxygen vacancies. The optimized Sn-Fe 2 O 3 exhibited exceptional sensing performance for NO 2 detection: ultra-high sensitivity ( Rg / Ra =2646.6 to 1 ppm NO 2 ), ultra-low limit of detection (10 ppb), and high selectivity.