Acid washing-assisted synthesis of porous Co3O4 nanosheet catalyst featuring efficient benzene oxidation performance

Abstract

Co-based catalysts exhibit considerable catalytic activity in oxidative reactions, yet challenges remain in synthesizing Co₃O₄ materials featuring both large surface area and high activity. Here, ultrathin La_0.029CoO_x nanosheets were post-treated with various concentrations of dilute nitric acid to obtain the two-dimensionally geometric Co₃O₄-H nanosheets catalysts. Among them, the resultant Co₃O₄-0.1H catalyst disclosed significantly enhanced catalytic activity, enabling to achieve 100 % conversion of benzene at 230 °C under an ultrahigh weight hourly space velocity (WHSV) of 60,000 mL·g⁻¹·h⁻¹. Additionally, the catalyst also displayed excellent catalytic durability and well catalytic stability over 5 cyclic tests and 45 h of long-period operation. A thorough characterization results revealed that the superior catalytic performance of Co₃O₄-0.1H was attributed to its distinct nanosheet morphology, high specific surface area and abundant surface defect sites. This work highlights the effectiveness and simplicity of acid washing treatment strategy in improving the catalytic oxidation activity of transition metal oxide catalysts.