Highly efficient photocatalytic Cr(VI) reduction and organic pollutants degradation of two new bifunctional 2D Cd/Co-based MOFs

Two new 2D metal-organic frameworks (MOFs), [Cd(bpy)(H2O)L](n) (BUC-66) and {Co(bpy)(H2O)L]center dot H2O}(2n) (BUC-67), (H2L = cis-1,3-dibenzyl-2-imidazolidone-4,5-dicarboxylic acid, bpy = 4,4 '-bipyridine), have been synthesized under hydrothermal conditions. These two 2D MOFs were used to carry out photocatalytic Cr(VI) reduction and organic pollutants degradation. The results revealed that both BUC-66 and BUC-67 displayed outstanding photocatalytic Cr(VI) reduction performances with reduction efficiency more than 98% within 30 min under UV light irradiation, much better than that of commercial P25 (24%). Also, BUC-66 and BUC-67 could photocatalytically decompose organic dyes. These two MOFs exhibited considerable photocatalytic activities in the Cr(VI)/organic dyes matrix. Upon UV light illumination for 30 min, the Cr(VI) reduction efficiency reached 100%, along with the organic dye (methyl orange) degradation efficiency being 85% (BUC-66) and 100% (BUC-67). Finally, a possible photocatalytical reaction mechanism have been proposed and verified in detail. (C) 2018 Elsevier Ltd. All rights reserved.