Pt Decorated Cofe2o4/Co3o4 Nanosheets Derived from 2d Fe-Co Mof for Enhanced Hcho Detection

Abstract

Highly sensitive and selective detection of volatile organic compounds (VOCs) is of great significance, and designing a suitable microstructure and constructing heterostructures are two main effective strategies for gas-sensing materials to achieve this goal. Herein, Pt nanoparticles decorated CoFe2O4/Co3O4 nanosheets were prepared by solution method for highly accurate detection of formaldehyde (HCHO), where the CoFe2O4/Co3O4 nanosheets were derived from two-dimensional Fe-Co metal-organic framework (MOF). The response (Rg/Ra) of ternary Pt/CoFe2O4/Co3O4 composite to 100 ppm HCHO at 280 °C can be calculated as 95.5, and it still exhibits a very high response to low concentration of HCHO (1.26 to 50 ppb gas) and a ultra-low limit of detection (LOD) of 6 ppb. The ternary composite also presents excellent reproducibility, selectivity and long-term stability. The first-principles calculations demonstrate that the Pt/CoFe2O4/Co3O4 model presents the most stable structure and the strongest adsorption capacity for HCHO. The high sensitivity of Pt/CoFe2O4/Co3O4 to HCHO can be mainly ascribed to the formation of multi-heterojunctions and the catalytic effect of Pt nanoparticles. This work provides a facile preparation of MOF-derived multi-heterojunction materials, and highlights superior gas-sensing performance to VOCs.

Keywords: Pt/CoFe2O4/Co3O4, nanosheets, Heterojunction, Gas sensing