Regulatory role of Lewis acid sites on Cu species in Cu/ZnO/Al2O3 sorbent and their effect on thiophene removal performance

Abstract

In the deep desulfurization of coke oven gas, a systematic understanding of how alumina Lewis acid sites regulate the structure of supported Cu species and their synergistic interaction remains lacking. Based on this, this study proposes a simple yet effective strategy: thermally treating the alumina support at different temperatures to modulate the distribution and strength of its surface Lewis acid sites, followed by the preparation of Cu/ZnO/Al₂O₃ sorbents via the deposition–precipitation method. Their desulfurization performance is systematically evaluated in a fixed-bed reactor to elucidate the impact of Lewis acid sites on the structural evolution of Cu species and their desulfurization behavior. The results indicate that Cu migrates toward Lewis acid sites during deposition, where it is more effectively anchored and dispersed. The electronic interaction between Cu and Lewis acid sites significantly enhance thiophene adsorption and activation, leading to improved desulfurization performance. In the desulfurization performance evaluation, the CZA-2 sorbent exhibited the superior performance at 200 ℃ and 5500 h⁻¹, achieving a breakthrough sulfur capacity of 43.3 mg/g, approximately 34 % higher than that of sorbents using commercial alumina supports.