A novel nano-sized Co3O4@C catalyst derived from Co-MOF template for efficient Hg0 removal at low temperatures with outstanding SO2 resistance

Co3O4 is a promising Hg0 removal catalyst for industrial application. Operating temperature and low sulfur resistance are two of the main problems that hinder its industrial application in Hg0 removal. Herein, a metal-organic framework (Co-BDC) was introduced as a sacrificial template to obtain the catalyst nano-sized Co3O4@C by calcination. Part of the organic ligands is carbonized during the calcination. Carbon wrapped Co3O4 and reduced metal agglomeration. The optimal Hg0 removal temperature of the existing cobalt oxide catalysts was always around 150 °C, but H2-TPR showed that the oxygen atoms on the Co3O4@C were more active than those on Co3O4, causing the Hg0 removal temperature window of Co3O4@C to shift to lower temperatures. The Hg0 removal efficiency of Co3O4@C could reach almost 100% even at 25 °C. In the meanwhile, Co3O4@C also showed a strong SO2 resistance at ambient temperature. Experimental results and characterization proved that SO2 did not compete with Hg0 on the surface of Co3O4 at low temperatures. On the contrary, it participated in the oxidation of Hg0. This is a great improvement for Co3O4 catalyst in Hg0 removal. It reduces the restrictions on the application of Co3O4 in Hg0 removal. Co3O4@C shows considerable potential as an Hg0 removal catalyst.