Catalytic behaviors of combined oxides derived from Mg/Al x Fe 1−x –Cl layered double hydroxides for H 2 S selective oxidation

• Published in: Catalysis science & technology 2015, Vol.5 (11), p.4991-4999
• Main Authors: Zhang, Xin, Wang, Zhuo, Tang, Yuyin, Qiao, Nanli, Li, Yang, Qu, Siqiu, Hao, Zhengping
• Format: Article
• Language: English
• ISSN: 2044-4753; 2044-4761
• DOI: 10.1039/C5CY00689A

A series of Mg 2 Al x Fe 1−x LDH compounds was synthesized by a one-step method. The structural and chemical properties were studied by various methods and the derived oxides were tested for H 2 S selective oxidation. It was observed that the iron species existed mainly in the form of isolated Fe 3+ species, α-Fe 2 O 3 , γ-Fe 2 O 3 and Fe 3 O 4 . Moreover, the nature of the iron oxides was varied with the rise in the iron content. Significantly, the catalysts exhibited high catalytic activity and reasonable durability at a relatively lower temperature and higher GHSV. The catalysts obeyed the step-wise mechanism for H 2 S selective catalytic oxidation. And the chemically adsorbed oxygen on the oxygen vacancies participated in the H 2 S selective oxidation reaction and played a key role in the H 2 S selective oxidation into elemental sulfur. The catalyst deactivation was due mainly to the deposit of elemental sulfur. Additionally, the small amount of the formed less active Fe 2 (SO 4 ) 3 species also led to catalyst deactivation.