Dual resistance to alkali metals and SO2: vanadium and cerium supported on sulfated zirconia as an efficient catalyst for NH3-SCR

Abstract

Vanadium and cerium supported on sulfated zirconia is an efficient SCR catalyst with dual resistance toward both potassium and SO₂ poisoning. To the best of our knowledge, no examples of catalysts with a tolerance to both alkali metals and SO₂ have been reported. Herein, the catalyst with a Ce : V molar ratio of 1 : 1 showed the highest activity (>97%) in the presence of potassium and SO₂. The formation of thermally stable Ce₂(SO₄)₃ disrupted the Ce(IV)/Ce(III) redox cycle, resulting in a significant deactivation of the CeSZ catalyst (93% to 63% in 400 min). Addition of a vanadium additive led to the transformation of CeO₂ to CeVO₄, thereby cutting off the reaction between CeO₂ and SO₂ and retaining the reactivity of the active sites. In addition, vanadium weakened the adsorption/oxidation of SO₂ on the catalysts and thereby enhanced the tolerance toward SO₂ by inhibiting the formation of ammonium bisulfate (NH₄HSO₄).