Evaluating the Contributions of Properties in Doping-modified Co-based Oxides to Oxidation of Volatile Organic Compounds

Abstract

Doping-modification is extensively employed to enhance the catalyst activity for VOCs oxidation. However, the specific interactions between doped metals and different VOC components remain unclear. This method can positively or negatively influence various catalyst properties, yet their contributions to catalytic activity remain unverified. Herein, the Co₃O₄ was doped with Ce, Mn, or Cu. The relative contributions of their properties to the catalytic performance for three typical VOCs (toluene, butyl acetate and acetone) were quantified by Analysis of Variance. The F-value followed the order as Co³⁺_/ Co²⁺> O_latt-s > O_ads > crystal size(Cs) ≈ BET specific surface area(S_BET) for all VOCs. The Co³⁺_/ Co²⁺ exhibited the prominent influence on the catalytic activity, followed by active oxygen species. Ce doping with the most significant positive effect on Co³⁺_/ Co²⁺, O_ads, S_BET and Cs exhibited the optimal catalytic performance for all VOCs. It achieved the low temperature for 90% VOC conversion(T₉₀), with 242℃ for toluene, 190℃ for butyl acetate and 187℃ for acetone, and maintained activity for over 5600 min. Mn doping with the most significant positive effect on O_latt-s, also promoted the catalytic activity, particularly for the oxygen-containing VOCs. In contrast, Cu doping with the inferior Cs and S_BET, slightly enhanced active oxygen species and almost unvarying Co³⁺_/ Co²⁺ could only slightly promote the catalytic activity for toluene and acetone. The established relationship between the doped metals, catalyst properties and the VOCs components, and the quantified contribution will provide strategy for the targeted modification of catalysts to efficiently oxidize VOCs.