Photocatalytic hydroxylation of benzene to phenol with dioxygen using sodium decatungstate

Copper-containing POM-based hybrid P2Mo22V4Cu4 nanocluster as heterogeneous catalyst for the light-driven hydroxylation of benzene to phenol

The current traditional phenol production process has many shortcomings, and the efficient and clean photocatalytic one-step oxidation to phenol is gradually attracting attention. Heteropolyacids (PMo10V2) with high-density Lewis acid active sites and excellent photoelectron transfer ability are ideal choices for catalytic reactions. In this study, a copper-modified isolated dimeric hybrid nanocluster, [Cu(pyim)2]2[Cu(pyim)2(P2MoVI20MoV2VIV4O82)]2·(H2O) (pyim = [2-(pyridin-2-yl)imidazole]), was synthesized by a convenient hydrothermal method. The structural analysis demonstrated that the compound was composed of metal-organic complexes containing pyim ligands, Keggin-type heteropolyacids, and transition metal copper ions. Remarkably, this not only solves the difficulty that the heteropolymeric acid cannot be recovered by dissolving in the solvent but also introduces the copper atom as a second active center. The catalyst exhibited a benzene conversion of 15.6% and a selectivity of 85.2% in a mixed solution of acetonitrile and acetic acid under optimal reaction conditions. After four catalytic cycles, the PXRD pattern proved that the catalyst was still stable. This study provides a good idea for photocatalytic reactions and other environmental applications.

Tungsten Catalysts for Visible Light Driven Ofloxacin Photocatalytic Degradation and Hydrogen Production

Some tungsten catalysts of interest that are synthesized are bismuth tungstate (BT) and Tetrabutylammonium decatungstate (TBADT), using two consolidated procedures. BT is used as a photo-catalyst for the simulated solar light degradation of ofloxacin (OFL) antibiotic under relevant real conditions (µg L−1, fresh water) with the limit of 0.05 g L−1 of catalyst. A quantitative drug decomposition occurred following a bi-exponential first-order law, with an efficiency comparable with the most used P25 TiO2 catalyst. The photocatalytic profiles of OFL at µg L−1 and mg L−1 were monitored by high-pressure liquid chromatography (HPLC) coupled with fluorescence (FD) and ultraviolet (UV) detectors. Additionally, the main photoproducts were identified by high-pressure liquid chromatography coupled to electrospray ionization in tandem with mass spectrometry (HPLC-ESI-MS/MS). The catalyst Tetrabutylammonium decatungstate (TBADT) was used as a catalyst to produce hydrogen from glucose and 2-propanol in aqueous solution, providing hydrogen gas evolution up to 10 µmol g−1 h−1.