Modification of Cu3(BTC)2 with Cobalt Ion for Adsorption and Visualized Detection of Formaldehyde Gas

In this paper, cobalt ion was employed to modify Cu 3 (BTC) 2 to improve the adsorption property for formaldehyde gas. The cobalt ion was doped during the synthesis of Cu 3 (BTC) 2 to form a product of CuCo-BTC. As the optimization assay indicated, when the molar ratio of the Co 2+ /Cu 2+ was 3/17, the adsorption amount for formaldehyde gas achieved the maximum, which is 1.6-fold to that of Cu 3 (BTC) 2 . ICP-MS, XPS, XRD, FT-IR, SEM and N 2 adsorption–desorption were used to investigate the structure and property of the CuCo-BTC. Subsequently, the adsorption kinetic process of the CuCo-BTC was assessed, the result suggests it coinciding to the pseudo first-order kinetic model which belongs to the physical adsorption process. The further assays indicated the CuCo-BTC possessing higher and faster colorimetric response to formaldehyde with indicator than other metal organic framework materials or common indicators. Therefore, it was utilized to fabricate a functional paper chip to perform the visualized detection of formaldehyde gas. The result displayed a sensitive response to formaldehyde gas in the concentration range of 0.02 ~ 0.08 mg/m 3 . Besides, the whole colorimetric assay merely takes 150 s, suggesting a favorable application prospect in the on-site test of detrimental gas.