Combustion synthesis of lanthanum oxide supported Cu, Ni, and CuNi nanoparticles for CO2 conversion reaction

The reverse water gas shift (RWGS) process is considered a feasible method for lowering greenhouse gas emissions by utilizing CO2 and converting it to CO. Herein, we evaluated the catalytic conversion of CO2 through the RWGS reaction over transition metal nanoparticles supported on lanthanum. Catalysts of selected active metals (Cu, Ni, and CuNi) on lanthanum oxide support were investigated in a packed bed tubular reactor within a temperature range of 100–600 °C to assess their catalytic activity and selectivity towards CO. The results of the catalyst's activity and stability experiments showed maximum CO2 conversions of 57%, 68% and 74% for Cu–La2O3, Ni–La2O3, and CuNi–La2O3, respectively, at 600 °C and excellent stability over a 1440-min time on stream (TOS) with a carbon deposition rate of less than 3 wt%. However, among all investigated catalysts, only the 1 wt% Cu–La2O3 catalyst displayed a CO selectivity of 100% at all the studied temperatures, whereas the nickel-containing catalysts showed selectivity for methane along with carbon monoxide. Furthermore, the morphological properties of the support and catalysts, as well as the effect of the reaction conditions on the catalysts surface, were studied using a variety of techniques, including XRD, TEM, SEM-EDX and TPR. The results showed promising potential for the application of transition metal catalysts on lanthanum oxide support for RWGS that could be extended to other hydrogenation reactions.