CF₄, one of the Perfluorocompounds (PFCs), also known as a greenhouse gas with high global warming potential. In this study, Zr/γ-Al₂O₃ catalysts were developed for CF₄ decomposition. The addition of Zr onto γ-Al₂O₃ achieves a high CF₄ conversion efficiency of 85% at 650 °C and maintain its activity for more than 60 h, which is obviously higher than that of bare γ-Al₂O₃ (50%). The mechanism involved in CF₄ decomposition over the Zr/γ-Al₂O₃ are clarified that the surface Lewis acidity sites are the main active center for CF₄ directly adsorbing and decomposing. The results of NH₃-TPD and FT-IR analyses suggest that the amount of Lewis acidity sites on catalyst surface increases significantly after the introduction of Zr, thereby enhancing the activity of catalyst for CF₄ decomposition. The results of XPS analyses confirms the electrons transfer from Zr to Al, which contribute to the increase in Lewis acidity sites. The results of this work will help the development of more effective catalysts for CF₄ decomposition.

CF₄ has a global warming potential of 6500 and possesses a lifetime of 50,000 years. In this study, we modified the HZSM-5 catalyst with Ce and sulfuric acid treatment. The S/Ce/HZSM-5 catalyst achieves 41% of CF₄ conversion at 500 °C, which is four times higher than that over Ce/HZSM-5, while the HZSM-5 exhibits no catalytic activity. The effects of modification were studied by using NH₃-TPD, FT-IR of pyridine adsorption, and XPS methods. The results indicated that the modification, especially the sulfuric acid treatment, strongly increased the Lewis acidic sites, strong acidic sites, and moderate acidic sites on catalysts, which are the main active centers for CF₄ decomposition. The mechanism of acidic sites increases by modification and CF₄ decomposition is clarified. The results of this work will help the development of more effective catalysts for CF₄ decomposition.

Resource utilization of SO₂ from flue gas is a key challenge for the green development of the smelting industry. Recovery of sulfur resources in the form of elemental sulfur (S⁰), which has a high market demand and is a current focus in the field of SO₂ treatment, can reduce the solid waste from desulfurization. In this study, it was found that Pb as a cathode material had good catalytic activity for the electrochemical reduction of SO₂ and good selectivity towards elemental sulfur. However, the cathode suffers from sulfur poisoning. The problem was resolved by introducing surfactant, specifically sodium dodecyl benzene sulfonate (SDBS), which significantly lowered the sulfur content ratio on the surface of the electrode from 31.82% to 2.17%. Through the optimization of electrocatalytic parameters, this method enables efficient conversion of SO₂ to S⁰, achieving a selectivity of 83% at pH = 0.25 and E = −0.8 V (vs. SCE).

This paper reports on a novel method to remove Hg⁰ in the wet scrubbing process using defect-rich colloidal copper sulfides for reducing mercury emissions from non-ferrous smelting flue gas. Unexpectedly, it migrated the negative effect of SO₂ on mercury removal performance, while also enhancing Hg⁰ adsorption. Colloidal copper sulfides demonstrated the superior Hg⁰ adsorption rate of 306.9 μg·g⁻¹·min⁻¹ under 6% SO₂ + 6% O₂ atmosphere with a removal efficiency of 99.1%, and the highest-ever Hg⁰ adsorption capacity of 736.5 mg·g⁻¹, which was 277% higher than all other reported metal sulfides. The Cu and S sites transformation results reveal that SO₂ could transform the tri-coordinate S sites into S₂²⁻ on copper sulfides surfaces, while O₂ regenerated Cu²⁺ via the oxidation of Cu⁺. The S₂²⁻ and Cu²⁺ sites enhanced Hg⁰ oxidation, and the Hg²⁺ could strongly bind with tri-coordinate S sites. This study provides an effective strategy to achieve large-capability adsorption of Hg⁰ from non-ferrous smelting flue gas.