DFT Insights into Adsorption and Oxidation of H2S/PH3 on CuO(111)

Abstract Industrial emissions of H2S and PH3 from submerged arc furnaces significantly hinder CO resource recovery and ecological environmental protection. While CuO-based catalysts exhibit positive removal performance toward these toxic contaminants, the atomic-level adsorption behaviors and underlying catalytic oxidation mechanisms remain poorly understood. This study employs density functional theory (DFT) calculations to systematically examine the reaction system. The results show that PH3 exhibits preferential adsorption at the Cu3f active site with a highest binding energy (-42.96 kJ/mol) , surpassing those of H2S (-36.53 kJ/mol) and O2 (-34.43 kJ/mol). Transition state calculations uncover distinct reaction pathways: H2S is oxidized to H2SO4 through hydroxyl (-OH) and sulfite (-SO3 ) intermediates, while PH3 is converted to H3PO4 via hydrogen transfer and P-O bond formation. Notably, although PH3 adsorbs more strongly on the catalyst surface, its catalytic oxidation process is associated with a higher activation energy barrier (113.8 kJ/mol) compared to H2S (86.3 kJ/mol). These findings elucidate the fundamental surface reaction processes and provide theoretical support for developing high-efficiency Cu-based catalysts for simultaneous desulfurization and dephosphorization in industrial off-gas treatment.