Abstract In this study, activity, selectivity and stability of vanadium catalysts supported on zirconia, hafnia, and alumina were examined in the oxidation of methanethiol and methanol to formaldehyde. The 3 wt-% vanadia–alumina catalyst with low VOx surface density showed the highest activity in the formaldehyde production. However, during the stability test, this catalyst deactivated due to the change in the oxidation state of vanadium from V5+ to V4+, decrease the amount of surface vanadium species and the formation of sulphates on the material surface. Zirconia and hafnia supported catalysts with high VOx surface density demonstrated better stability in the reaction conditions, but their activity in the formaldehyde production was lower. One reason for the lower activity might be the formation of metal-mixed oxide phases between vanadia and the support, which could also explain the decreased sulphur deposition on zirconia and hafnia after vanadium impregnation.

中文翻译：

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钒催化剂在挥发性有机化合物排放生产甲醛中的活性、选择性和稳定性

摘要 本研究考察了以氧化锆、铪和氧化铝为载体的钒催化剂在甲硫醇和甲醇氧化制甲醛过程中的活性、选择性和稳定性。具有低 VOx 表面密度的 3 wt-% 钒-氧化铝催化剂在甲醛生产中表现出最高的活性。然而，在稳定性测试过程中，由于钒的氧化态从 V5+ 变为 V4+，该催化剂失活，减少了表面钒物质的数量和材料表面硫酸盐的形成。具有高 VOx 表面密度的氧化锆和铪负载催化剂在反应条件下表现出更好的稳定性，但它们在甲醛生产中的活性较低。