Exploiting the multifunctionality of a designed vanadium-doped ZnO hybrid for selective catalytic reduction of NOx and electrochemical applications

Abstract

This study concerns the fabrication of zinc oxide enriched with vanadium, and evaluation of its performance in SCR process and as an electrode component for electrochemical applications. The material’s preparation was optimized in terms of the concentration (10–25 wt%) and type of the vanadium precursor (NaVO3 or NH4VO3). The effectiveness of ZnO/V synthesis was proved by the results of EDS and XRF analysis, which confirmed the expected percentage contribution of zinc, vanadium and oxygen, as well as FTIR spectra, which contained bands corresponding to vibrations of Zn–O, VO and V–O–V bonds. Increasing the concentration of vanadium up to 10 wt% resulted in an increase in the material’s surface area, which reached a maximum value of 75 m2/g for ZnO/V 9:1. Irrespective of the amount and type of vanadium precursor used, all samples exhibited a crystalline hexagonal wurtzite structure similar to pristine zinc oxide. Moreover, the incorporation of vanadium into the ZnO structure caused a significant reduction in the zeta potential at particular pH values for all tested samples. The material’s multifunctionality was verified in SCR catalysis and in electrochemical tests. In the catalytic tests, ZnO/V with a ZnO:V ratio of 3:1 attained the highest nitrogen oxides conversion rate, which reached 67% at 450 °C. In turn, cyclic voltammetry tests not only showed the presence of peaks corresponding to the vanadium oxide, but also indicated the possibility of using the obtained hybrid as a feed material in a lithium-ion cell.