A bifunctional POM‐based Cu‐viologen complex with mixed octamolybdate clusters for rapid oxidation desulfurization and effective photogeneration of hydrogen

Abstract The design and synthesis of catalysts for the oxidation desulfurization and production of hydrogen are extremely important for solving environmental pollution and energy shortage. Herein, a novel bifunctional [α‐Mo 8 O 26 ] 4− /[β‐Mo 8 O 26 ] 4− ‐based Cu‐viologen complex H 4 [Cu 2 I Cl 2 (Hbcbpy) 4 ][α‐Mo 8 O 26 ][β‐Mo 8 O 26 ]·H 2 O (BHU‐2, Hbcbpy = 1‐(4‐carboxybenzyl)‐4,4’‐bipyridinium) was synthesized and characterized by single‐crystal X‐ray diffraction (XRD), infrared radiation spectra, powder X‐ray diffraction (PXRD) and X‐ray photoelectron spectroscopy (XPS) spectra. The structural characteristic of BHU‐2 is the presence of two types of octamolybdate clusters [α‐Mo 8 O 26 ] 4− /[β‐Mo 8 O 26 ] 4− and a new binuclear Cu I ‐Hbcbpy complex linked by Cl‐bridges [Cu 2 I Cl 2 (Hbcbpy) 4 ] 4+ . BHU‐2 as a heterogeneous catalyst exhibits excellent activities to the oxidation desulfurization and photocatalytic hydrogen production. At room temperature, BHU‐2 can catalyze 96% conversion of methyl phenyl sulfide with 98% selectivity, and the process obeys the pseudo‐first‐order reaction kinetic with the half‐life of 9.6 min. The notorious 2‐chloroethyl ethyl sulfide can achieve 99% conversion with 98% selectivity within only 1 min at the presence of BHU‐2, and the turnover frequency (TOF) is up to 7400 h −1 . BHU‐2 also exhibits high catalytic activity for the oxidation of other aromatic and aliphatic thioethers within short time at room temperature. Furthermore, BHU‐2 shows a high catalytic activity for visible‐light‐driven hydrogen evolution with an H 2 evolution rate of 1677.85 µmol·g −1 ·h −1 within 10 h. Moreover, the catalytic activities do not decrease evidently after three cycles, revealing the prominent structural stability and recyclability.