PHYSICOCHEMICAL PROPERTIES AND CATALYTIC ACTIVITY OF A 0.5% RH/13X CATALYST IN THE CO₂ HYDROGENATION REACTION

Abstract

A 0.5% Rh/13X catalyst was synthesized by incipient wetness impregnation, and its structural, physicochemical, and catalytic properties were investigated in the carbon dioxide hydrogenation reaction. The morphology, elemental composition, and phase composition of the catalyst were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction analysis. The surface adsorption properties were studied using CO₂ temperature-programmed desorption (CO₂-TPD), while the reduction behavior was examined by H₂ temperature-programmed reduction (H₂-TPR). Catalytic activity was evaluated in a fixed-bed flow reactor over the temperature range of 180–700 °C. It was established that rhodium deposition did not disrupt the crystalline structure of the 13X zeolite, while the active phase was characterized by high dispersion and the presence of readily reducible surface species. The catalyst was shown to contain basic sites of different strengths that facilitate carbon dioxide adsorption. Catalytic tests demonstrated that CO₂ conversion increased with temperature, reaching a maximum value of 93.5%. The obtained results confirm the potential of the 0.5% Rh/13X catalyst for CO₂ hydrogenation to methane.