Preparation of Ni/ZnCo₂O₄@ZnO composite metal oxide adsorbent and its adsorption desulfurization and regeneration performance

Metal Co was introduced into ZnO by co-precipitation to form composite metal oxides as the desulfurization agent with different Co contents, with which the desulfurization activity and regeneration performance were investigated. The systematic characterization of the structure and properties of the desulfurization agent using XRD, TEM, N₂ adsorption and desorption, XPS and H₂-TPR confirmed that the composite metal oxide desulfurization agent had the Ni/ZnCo₂O₄@ZnO structure. The formation of ZnCo₂O₄ in the composite metal oxides desulfurization agent facilitated the particle size reduction, dispersion enhancement and specific surface area increase of the desulfurization agent, which also acted as an adsorbent for H₂S indicated by the XRD analysis, improving the sulfur adsorption capacity of the desulfurization agent. The desulfurization performance of all the composite metal oxide desulfurization agents was higher than that of Ni/ZnO, in which the desulfurization agent NZCo-3 with a molar ratio of Zn∶Co of 1∶1 exhibited the optimal desulfurization performance, and the desulfurization rate was 100% at a reaction temperature of 300 ℃, a hydrogen pressure of 3 MPa, a mass-air velocity of 2.2 h⁻¹, and a hydrogen-oil ratio of 300, and the excellent desulfurization performance was maintained after 6 cycles. The results of this study provide new ideas for the rational design of Ni/ZnO desulfurization agent to improve its desulfurization and regeneration performance.