In this work, GdMnO3 material is successfully prepared using sol-gel method and GdMn2O5/GdMnO3 materials are in-situ generated by acid treatment. These materials are investigated and applied as catalysts for oxygenated VOC complete oxidation. The evaluation results show that GdMn2O5/GdMnO3-1.00 exhibits a remarkable increase in catalytic activity (T-50% = 198 degrees C and T-90% = 225 degrees C) of 2-ethoxyethanol oxidation when compared with the initial sample GdMnO3 (T-50% = 223 degrees C and T-90% = none). Characterization analyses show that acid treatment can result in the significant improvement of specific surface area from 20.502 m(2).g(-1) to 67.952 m(2).g(-1), abundant surface Mn4+ content and active oxygen, excellent reducibility at low temperature in GdMn2O5/GdMnO3-1.00 sample. In-situ DRIFTS results point out that the main functional groups such as v(as)(OCO), v(as)(COO), v(s)(C-O) are formed in the process of 2-ethoxyethanol oxidation over GdMn2O5/GdMnO3-1.00 sample and some by-products including ethanol, 2-ethoxyethyl acetate, acetic acid, carbonic acid, 2-ethoxyethyl 2-methoxyethyl ester, ethane and 1,1'-oxybis[2-methoxy-] can be produced at a reaction temperature of 200 degrees C. Additionally, in-situ DRIFTS studies indicate the presence of gas-phase O-2 plays a vital role in facilitating 2-ethoxyethanol deep oxidation to final products. (C) 2020 Elsevier Inc. All rights reserved.