Copper–iron catalyst supported on oxygen vacancy–containing titanium dioxide for deep ambient-temperature desulfurization

Abstract

Efficient H2S removal from gas streams is essential for mitigating environmental pollution, preventing catalyst poisoning, and reducing equipment corrosion. Consequently, the corresponding catalysts, particularly those enabling room-temperature desulfurization, are highly sought after. To address this need, we herein prepared a copper (Cu)–iron (Fe) catalyst supported on titanium dioxide with oxygen vacancies (Cu-Fe/Vo-TiO2) via incipient wetness coimpregnation and evaluated its H2S removal ability under ambient conditions. The results of Brunauer–Emmett–Teller analysis, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analyses revealed the presence of oxygen vacancies, Cu(NO3)2, and FeOOH, which synergistically enhanced catalytic activity. Specifically, oxygen vacancies facilitated electron transfer and hydroxyl radical generation, nitrate groups promoted the oxidation of H2S to elemental sulfur and sulfate, and FeOOH enhanced the redox properties of the catalyst, promoted sulfur oxidation, and formed stable sulfur intermediates. Cu-Fe/Vo-TiO2 exhibited desulfurization capacities of 56.1 and 161.6 mg S g−1 at H2S concentrations of 10 and 100 mg L−1, respectively, and achieved nearly quantitative removal within 10 min. Calcination and chloride precursor control experiments revealed that nitrate group removal decreased NO release and desulfurization efficiency, confirming the active role of these groups in the reaction mechanism. Thus, this work highlights the potential of Cu-Fe/Vo-TiO2 as a highly efficient and sustainable catalyst for H2S removal, eliminating the need for external energy inputs, addressing the limitations of conventional desulfurization methods, and facilitating the development of advanced multimetal catalysts for industrial desulfurization and air purification.