Low-temperature catalytic oxidation of formaldehyde over Co₃O₄ catalysts prepared using various precipitants

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• 作者：Zeyun Fan ; Zhixiang Zhang ; Wenjian Fang ; Xin Yao ; Guchu Zou ; Wenfeng Shangguan ; ^{shangguan@sjtu.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Formaldehyde oxidation ; Catalysis ; Cobalt oxide ; Precipitation method ; Potassium ion
• 刊名：Chinese Journal of Catalysis
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：37
• 期：6
• 页码：947-954
• 全文大小：741 K

文摘

Co₃O₄ catalysts prepared with different precipitants (NH₃·H₂O, KOH, NH₄HCO₃, K₂CO₃ and KHCO₃) were investigated for the oxidation of formaldehyde (HCHO). Among these, KHCO₃-precipitated Co₃O₄ (KHCO₃-Co) was the most active low-temperature catalyst, and was able to completely oxidize HCHO at the 100-ppm level to CO₂ at 90 °C. In situ diffuse reflectance infrared spectroscopy demonstrated that hydroxyl groups on the catalyst surface were regenerated by K⁺ and CO₃^2–, thus promoting the oxidation of HCHO. Moreover, H₂-temperature programmed reduction and X-ray photoelectron spectroscopy showed that employing KHCO₃ as the precipitant increased the Co³⁺/Co²⁺ molar ratio on the surface of the Co₃O₄ catalyst, thus further promoting oxidation. Structural characterization revealed that catalysts precipitated with carbonate or bicarbonate reagents exhibited greater specific surface areas and pore volumes. Overall, these data suggest that the high activity observed during the Co₃O₄ catalyzed oxidation of HCHO can be primarily attributed to the presence of K⁺ and CO₃^2– on the Co₃O₄ surface and the favorable Co³⁺/Co²⁺ ratio.