Preparation of Cu-Fe composite metal oxide loaded SBA-15 and its capacity for simultaneous catalytic oxidation of hydrogen sulfide and phosphine

Abstract

A series of CuX-SBA-15 and Cu45-FeY/SBA-15 catalysts were used for simultaneous removal of H2S and PH3. The materials were prepared by a wet impregnation method, and the roles of copper and iron were considered important factors in this study. Test results showed that the addition of moderate iron could dramatically improve the catalytic oxidation capacity of Cu45/SBA-15, and the Cu45-Fe8/SBA-15 sample could achieve the best simultaneous removal performance. The breakthrough adsorption capacities were identified as 31.86 mgS and 120.05 mgP per gram fresh catalysts, respectively. To investigate the relationship between activity and metal species, the materials were characterized through FT-IR, XRD, XPS, BET, TEM, NH3-TPD, in situ IR and ICP-OES methods. The results indicated that the excellent performance in simultaneous removal of H2S and PH3 is likely due to the levels of Cu-O groups, generation of Lewis acid sites and high dispersion of metal oxides. FTIR, XRD and XPS analysis showed that the removal capacity of catalysts depended on the number of Cu-O groups that came from Cu2(OH)3NO3. Moreover, NH3-TPD, TEM and XPS results indicated that iron species played an important role in generating Lewis acid sites and uniformly dispersing active components, which may prevent the aggregation of Cu species on the catalyst surface. BET results showed that the pore diameter distribution in the range of 5–6 nm and 14–19 nm may play an important role in improving the removal performance of H2S and PH3. In addition, the in situ IR analysis showed that the presence of iron species may hinder the accumulation of phosphate species. The pore structure was not the main factor in active performance, but the pore diameter distribution in the range of 11–19 nm may have a promoting effect on simultaneous removal of H2S and PH3. The deactivation cause can be attributed to the loss of CuO/Fe2O3 and accumulation of P/S/sulfate/phosphate.