Comprehensive study of H sub(2)S selective catalytic oxidation on combined oxides derived from Mg/Al-V sub(10)O sub(28) layered double hydroxides

• Published in: Applied catalysis. B, Environmental Environmental, 2015-10, Vol.176-177, p.130-138
• Main Authors: Zhang, Xin, Tang, Yuyin, Qiao, Nanli, Li, Yang, Qu, Siqiu, Hao, Zhengping
• Format: Article
• Language: English
• Subjects: Aluminum; Catalysis; Catalysts; Distortion; Durability; Oxidation; Oxides; Vanadium
• ISSN: 0926-3373
• DOI: 10.1016/j.apcatb.2015.03.057

A series of Mg sub(2)Al-V sub(10)O sub( 28)-LDH (named V-LDH) were synthesized using ion-exchange method, and the derived oxides were investigated for H sub(2)S selective oxidation. The physicochemical properties of the catalysts were assessed by various methods. It was observed that vanadium species existed mainly in the form of isolated V super(5+) in distorted [VO sub(4)], Mg sub(3)V sub(2)O sub(8), and Mg sub(2)V sub(2)O sub(7). Moreover, there was a large amount of V super(4+) species (>25%), mainly formed with vanadyl bonds. Significantly, the catalysts exhibited excellent catalytic performances at relatively low reaction temperatures (100-200 [degrees]C). Furthermore, the catalyst containing 10.6 wt% vanadium (8V-LDO) was highly durable at a relatively low temperature (160 [degrees]C) and a high gas hourly space velocity (GHSV, 24,000 h super(-1)), which can proceed consecutively for 100 h without notable deactivation. In the reaction process, the gradually produced sulfate species reacted with V super(4+) species to form less active VOSO sub(4) species, which improved the redox property of V super(5+). The catalysts obeyed a step-wise mechanism for H sub(2)S selective catalytic oxidation. The excellent durability can be ascribed to the fact that the content of moderate basic sites was kept and the redox property of V super(5+) was improved.