Single Atom Catalysts-Anchored Carbon Nitride: Dual Sensitisation and Morphological Control of Metal Oxide Nanofibers

Abstract

Reducing the size of noble metal catalysts is one of the key goals in designing catalytic systems with maximum efficiency. Sensitisation of metal oxides with noble metals in a form of single-atoms or a few-atoms-cluster is hence of great interest in various fields including photocatalysis and catalytic conversions [1][2]. With this respect, we employed single atom-anchored shredded carbon nitride nanosheets (Pt-MCN) as a catalyst that can work as both dual-sensitizer and a morphological modifier of tin oxide nanofibers (SnO2 NF). Through electrospinning followed by a calcination process, it is possible to synthesize metal oxide nanofibers uniformly functionalized with Pt-MCN. Thermally stable carbon nitride survives through the calcination step and forms heterojunctions with tin oxide, hence acts as a dual-sensitizer together with the atomic scale Pt, and at the same time, induces the formation of peculiar nano-fiber-in-tubes (FIT) instead of nanofibers. Atomic scale Pt strongly bound on MCN experiences only a minor degree of agglomeration even after calcination, and the majority remains in singly dispersed state, as confirmed by HAADF-STEM analysis. This structure demonstrates an excellent sensing performance toward formaldehyde gas, and in particular, showing an extremely low experimentally determined limit of detection (LOD = 50 ppb).