Dawson-Type Polyoxometalates Functionalized Porphyrin-Based Covalent Organic Frameworks for Visible-Light-Driven Oxidation of Sulfides and Detoxification of Mustard Gas Simulants

Photocatalytic oxidation of sulfides to sulfoxides and detoxification of mustard gas simulant 2-chloroethyl ethyl sulfide (CEES) to nontoxic 2-chloroethyl ethyl sulfoxide (CEESO) is an area of great interest in green chemistry. Herein, two hybrids based on Dawson-type polyoxometalate anions and porphyrin-based covalent organic frameworks, P 2 W 18 –COF ( 1 ) and P 2 Mo 18 –COF ( 2 ), (COF = porphyrin-based covalent organic frameworks), were synthesized via hydrothermal reaction and characterized by infrared spectroscopy, X-ray photoelectron spectroscopy (XPS) spectroscopy, ultraviolet–visible (UV–vis) diffuse reflectance spectra (DRS), etc. With powerful visible-light harvesting properties of porphyrin-based covalent organic frameworks (COFs) and abundant photocatalytic active sites provided by Dawson-type polyoxometalate, these hybrids exhibit outstanding photocatalytic activity in the oxidation of sulfides and in the detoxification of CEES under 10 W white light-emitting diode (LED) light irradiation with O 2 as an oxidant. Notably, P 2 W 18 –COF shows unparalleled photocatalytic efficiency, in which the conversion of methyl phenyl sulfide is 99% in 18 min and the degradation of CEES is 99% in 10 min. In addition, P 2 W 18 –COF can be recycled 12 times without decreasing the photocatalytic efficiency, marking the excellent durability of P 2 W 18 –COF as a heterogeneous catalyst. The photocatalytic mechanism reveals that O 2 •– arising from the electron transfer process and 1 O 2 resulting from the energy transfer process are present in the photocatalytic reaction.