Activation of Cu3(MoO4)2(OH)2 with the hydrazine-driven cation reduction into a highly efficient catalyst for the reduction of organic dyes and heavy metals ion

Monoclinic lindgrenite (Cu 3 (MoO 4 ) 2 (OH) 2 )-like CuMoOS oxysulfide catalyst with high catalytic activity in the dark was synthesized by a facile method. Hydrazine reduced cations to increase Cu + and Mo 4+ proportions, sulfur doping was used to diminish the problem of poor stability caused by the excessive deviations of the catalyst from electric neutrality due to the high Cu + and Mo 4+ concentrations. The ratios of Cu + /Cu 2+ and Mo 4+ /Mo 6+ ions affected the catalytic activity of CuMoOS catalysts. The CuMoOS with a Cu + /(Cu + +Cu 2+ ) ratio of 0.708 showed abundant oxygen vacancies and the best catalytic reduction effect. Through controlling the Cu + content of the catalyst, its defective structure, and electron transfer resistance, the reduction reaction with NaBH 4 can be effectively adjusted. CuMoOS-3 catalyst shows a complete catalytic reduction of 4-NP (50 ppm) within 4 min 50 ppm MB, RhB and MO organic dyes were completely reduced within 4 min, 6 min, and 8 min, respectively. At the same time, Cr 6+ , as a model heavy metal ion , was completely reduced in 12 min, and its pseudo-first-order reaction kinetic constant reached 0.1709 min −1 . Good stability was kept after six cycling experiments. Therefore, the high-efficiency CuMoOS catalyst synthesized by green procedures displays the potential for industrial application.