Trace doping of cobalt oxide using lanthanum for effective catalytic oxidation of carbon monoxide

• Published in: New journal of chemistry Vol. 47; no. 21; pp. 1289 - 1295
• Main Authors: Zhicheng, Zhou, Tingting, Jiang, Tao, Liu, Shourong, Zheng
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 30.05.2023
• Subjects: Carbon monoxide; Catalysts; Catalytic activity; Catalytic oxidation; Chemical synthesis; Cobalt oxides; Doping; Hydrophobicity; Lanthanum; Oxidation resistance; Water resistance
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d3nj01005h

To improve the catalytic activity of Co 3 O 4 for CO oxidation, we synthesized a series of Co 3 O 4 catalysts ( x %La-Co 3 O 4 ) with different La doping amounts using the deposition-precipitation method and investigated their catalytic activities and water resistance. The results indicated that the trace doping of La ( i.e. , 1.0-3.0 atom%) significantly improved the catalytic activity of Co 3 O 4 for CO oxidation. The main reason was that the doped La increased the content of Co 3+ in Co 3 O 4 , which was the main active Co species for CO oxidation. In addition, doping with La improved the water resistance and catalytic stability of Co 3 O 4 under wet conditions. Pure Co 3 O 4 was dramatically deactivated within a short period (the CO conversion decreased by 80% in 1 h), while 2%La-Co 3 O 4 maintained a CO conversion of over 75% within 15 h. The improved water resistance of 2%La-Co 3 O 4 was mainly due to the reduced hydroxyl content on the Co 3 O 4 surface, which increased the surface hydrophobicity of Co 3 O 4 . This work is expected to provide a strategy for the preparation of water-resistant and highly active Co 3 O 4 catalysts for CO oxidation. Trace doping La into Co 3 O 4 enhanced the catalytic activity and water resistance for CO oxidation significantly.