Preparation of Cu1conox Catalysts by Co-Precipitation Method for Catalytic Oxidation of Toluene

Abstract

Volatile organic compounds (VOCs) have been idemtified as a significant environmental concern, as well as a potential human health. Consequently, it is of practical significance to diminish VOCs emissions. In this work, a series of Cu1ConOx (n=1, 2, 4, 8, 12) bimetallic oxide catalysts with varying Cu/Co ratios are synthesised via the co-precipitation method. Among these catalysts, the Cu1Co8Ox catalyst exhibits the best catalytic performance for the catalytic oxidation of toluene, with T20 = 178°C and T90 =202°C, at a toluene concentration of 1,000 mg/m3 and a weight hour space velocity of 30,000 mL/(g·h). Moreover, the Cu1Co8Ox catalyst demonstrates the smallest apparent activation energy (Ea = 33.7 kJ/mol) for the catalytic oxidation of toluene. In addition, the stability of the Cu1Co8Oxcatalyst is investigated, which shows excellent stability in both 5 cycle stability test and 25 h long-term stability test. Meantime, the physicochemical properties of the catalysts are investigated using XRD, FT-IR, SEM, EDS, BET, TG, O2-TPD, H2-TPR and XPS. These results indicate that the doping of moderate amount of Cu, which results in the formation of strong Co-Cu interactions on the catalysts, improves the physicochemical properties of the Cu1Co8Ox catalysts, e.g., resulting in more oxygen vacancies, richer surface active oxygen species, better low-temperature redox properties, higher Co3+/Co2+ and higher Oads/OLatt ratios. This work describes a non-precious metal catalyst with significant potential for application in the removal of VOCs.

Keywords: Catalytic oxidation, non-precious metal catalysts, Toluene, Cobalt Tetraoxide, Co-precipitation Method