Preparing and Optimization of Cerium-Lanthanum-Cobalt Ternary Mixed Oxide as Catalyst for SO₂ Reduction to Sulfur

Abstract

In this work, various ternary cerium oxide/lanthanum oxide/cobalt oxide (Ce/La/Co) nanocatalysts were synthesized by co-precipitation method based on response surface methodology (RSM). The optimum predicted surface area was found to be 67.6 m 2 g −1 at calcination temperature of 650℃, La content of 10.0 wt%, and Co content of 8.0 wt%. Average crystal size of optimum ternary Ce/La/Co catalyst was estimated 11.4 nm. The confirmation tests revealed that experimental data can be predicted well by the model. Furthermore, the prepared catalysts were evaluated by Brunauer-Emmett-Teller (BET), Barrett-Joyner-Halenda (BJH), X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) and NH3 temperature programmed desorption (NH3-TPD) analyses. The characterization results confirmed that ternary Ce/La/Co catalysts were successfully synthesized. Also, the NH3-TPD result showed that total active sites of optimum ternary Ce/La(10)/Co(8) catalyst with La content of 10.0 wt% and Co content of 8.0 wt% was greater than that of single cerium oxide catalyst. The optimum synthesized catalyst was tested for SO2 reaction by methane to sulfur. SO2 conversion and selectivity of catalysts at various temperatures were determined. The better performance of Ce/La/Co optimum catalyst at different temperatures was obtained for SO2 reduction. Also the selectivity of the optimum catalyst for production of sulfur is better than other catalysts.

Reduction of SO2 to Elemental Sulfur in Flue Gas Using Copper-Alumina Catalysts

“…Catalysts for the reduction of SO 2 to elemental sulfur using CH 4 have included bauxite [18], alumina [19][20][21], metal oxides, and sulfdes supported on alumina and activated carbon [22][23][24][25][26], along with transition metal sulfdes [27], ferromanganese nodules [28], and cobalt oxide on diferent supports [29]. Cerium oxide has also demonstrated signifcant catalytic activity in this context [30][31][32][33][34][35]. Te application of plasma for catalytic reduction of sulfur dioxide using FeS/Al2O3 has also been subject to investigation [17].…”