MOF-derived, carbon-mediated construction of a hierarchical rod-shaped MoO3/Co3O4 heterojunction towards efficient triethylamine detection†

Abstract

The efficient construction of a MoO₃-based heterojunction can contribute toward enhancing the triethylamine-sensing ability, yet considerable challenges remain. In this study, a novel hierarchical rod-like MoO₃/Co₃O₄ heterostructure was constructed through a metal–organic framework (MOF)-derived, carbon-mediated strategy. Benefiting from the specific structural characteristic (increased contents of adsorbed oxygen species and catalytic Co³⁺) and synergistic catalytic activity of two transition metal oxides (MoO₃ and Co₃O₄), the gas sensor based on this MoO₃/Co₃O₄ heterojunction exhibited superior selectivity and a good response (R_a/R_g = 174.5/100 ppm) to triethylamine (TEA), with a real detection limit as low as 0.1 ppm. This gas-sensing result is considerably higher those reported in many recent studies, indicating the competitive potential of this material for TEA-sensing application. Finally, an in situ DRIFTS analysis was conducted to reveal the possible intermediates (C₂H₄ and NH_x) and the reaction pathway of TEA over this MoO₃/Co₃O₄ surface. This work presents a new avenue for constructing multi-component heterostructures assisted by the in situ MOF-derived carbon.