Excellent photoreduction performance of Cr(vi) over (WO4)2−-doped metal organic framework materials†
Abstract
A new conductive metal–organic-framework (MOF) photocatalyst, (WO4)2−-doped bismuth terephthalate (referred to as nNa2WO4BiBDC), was synthesized and characterized by varying the precursor molar ratio (n = 0.1, 0.3, 0.4, and 0.5) of Na2WO4/Bi(NO3)3 in the presence of terephthalic acid through a one-pot solvothermal process. This study found that doping (WO4)2− into BiBDC enhanced the separation of photo-generated carriers, improved the photocatalytic properties of bismuth terephthalate (BiBDC), and enabled the application in Cr(VI) reduction under UV light irradiation with the synergic effect from citric acid acting as a hole scavenger. Among all the precursor ratios of Na2WO4/Bi(NO3)3 used, 0.4Na2WO4BiBDC has the optimum performance, leading to triple gain in reduction efficiency for undoped BiBDC. The synthetic strategy to dope (WO4)2− into a layered MOF as a viable option for modification of MOFs was demonstrated in this study. Finally, the photoreduction of Cr(VI) by (WO4)2-doped bismuth terephthalate enables a new promising wastewater treatment option.