A series of CuO-ZnO-TiO2-ZrO2 catalysts were prepared by a facile solid-state route, and the effects of adding citric acid or oxalic acid on the physicochemical properties and catalytic performance for CO2 hydrogenation to methanol were investigated. The catalysts were characterized by several techniques, including X-ray diffraction (XRD), N-2 adsorption, transmission electron microscopy (TEM), reactive N2O adsorption, X-ray photoelectron spectroscopy (XPS), atomic absorption spectroscopy (AAS), temperature-programmed reduction with H-2 (H-2-TPR), and adsorption of CO2 followed by temperature programmed desorption (CO2-TPD). The results reveal that the addition of assistant complexing agents can improve the CuO dispersion in the catalysts and increase the metallic Cu surface area, and consequently greatly increase the CO2 conversion and methanol yield, with oxalic acid being a more effective assistant complexing agent than citric acid. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.