Confining isolated Pt atoms into the porous SnO2 for efficient gas sensing

Abstract

Highly dispersed isolated sites offer opportunities to rationally design sensing materials with desired performance, but their stability under harsh reaction conditions is still challenging. Herein, we deposited the highly dispersed atomic layer deposition (ALD) platinum (Pt) species into optimized porous SnO2 nanorods derived from the Sn-based metal organic frameworks (MOFs). With confining isolated Pt into porous SnO2, the optimum operating temperature of the sensor based on SnO2–Pt2 nanorods was decreased from 275 °C to 190 °C. And the response (Ra/Rg) to 5 ppm acetone was improved from 2.63 to 6.33, along with the decrease of response time from 23 s to 9 s. Combined with X-ray adsorption, near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) and density functional theory (DFT) simulation, the highly dispersed Pt confined within SnO2 nanorods are confirmed to heighten the adsorption of acetone at working temperature and lower the reaction activation energy. The confined structure enriches the acetone in hole, further enhancing its adsorption on Pt. The highly dispersed isolated Pt sites and confined effects dramatically promote the sensing performance. The understanding of structure-activity relationships offers a novel strategy to design the ultrasensitive and stable acetone sensing materials, and it shows potential applications in design of other gas sensing or catalytic materials.