Evaluating redox reactivity of CuO-based oxygen carriers synthesized with organometallic precursors

Abstract

The highly efficient CuO-based oxygen carrier is prospectively applied in chemical-looping combustion process. The metal precursors and synthetic methods greatly affect the performance of the synthetic CuO-based oxygen carriers. The inorganic precursors are commonly used to synthesize CuO-based oxygen carriers, while the organometallic precursors are scarcely adopted. In this work, the organometallic copper precursor [copper (II) acetate] and three other different organometallic support precursors (magnesium l-lactate hydrate, silicon tetraacetate and magnesium acetate) were adopted to produce CuO-based oxygen carriers via the methods of wet-mixing and spray-drying, respectively. It is found that the synthetic oxygen carriers incorporated with inert supports (MgO and SiO2) exhibit remarkably stable redox reactivity, compared to the pure CuO. Moreover, the redox reactivity of the MgO-incorporated CuO-based oxygen carriers is superior to that of the SiO2-incorporated CuO-based oxygen carriers. It is mainly attributed to the higher Tammann temperature of MgO (1549 K) compared to that of SiO2 (937 K), which more effectively contribute CuO to inhibit particle growth and agglomeration due to sintering. Additionally, the MgO-incorporated CuO-based oxygen carriers prepared via scalable spray-drying method also exhibit the relatively high redox reactivity. It indicates that the spray-dried, synthetic CuO-based oxygen carriers from organometallic precursors possess the potential to be industrialized amplification.