Single-Atom Pt Stabilized on One-Dimensional Nanostructure Support <i>via</i> Carbon Nitride/SnO₂ Heterojunction Trapping

Abstract

Catalysis with single-atom catalysts (SACs) exhibits outstanding reactivity and selectivity. However, fabrication of supports for the single atoms with structural versatility remains a challenge to be overcome, for further steps toward catalytic activity augmentation. Here, we demonstrate an effective synthetic approach for a Pt SAC stabilized on a controllable one-dimensional (1D) metal oxide nano-heterostructure support, by trapping the single atoms at heterojunctions of a carbon nitride/SnO₂ heterostructure. With the ultrahigh specific surface area (54.29 m² g^-1) of the nanostructure, we obtained maximized catalytic active sites, as well as further catalytic enhancement achieved with the heterojunction between carbon nitride and SnO₂. X-ray absorption fine structure analysis and HAADF-STEM analysis reveal a homogeneous atomic dispersion of Pt species between carbon nitride and SnO₂ nanograins. This Pt SAC system with the 1D nano-heterostructure support exhibits high sensitivity and selectivity toward detection of formaldehyde gas among state-of-the-art gas sensors. Further <i>ex situ</i> TEM analysis confirms excellent thermal stability and sinter resistance of the heterojunction-immobilized Pt single atoms.