Modifications in the Composition of CuO/ZnO/Al₂O₃ Catalyst for the Synthesis of Methanol by CO₂ Hydrogenation

Renewable methanol, obtained from CO₂ and hydrogen provided from renewable energy, was proposed to close the CO₂ loop. In industry, methanol synthesis using the catalyst CuO/ZnO/Al₂O₃ occurs at a high pressure. We intend to make certain modification on the traditional catalyst to work at lower pressure, maintaining high selectivity. Therefore, three heterogeneous catalysts were synthesized by coprecipitation to improve the activity and the selectivity to methanol under mild conditions of temperature and pressure. Certain modifications on the traditional catalyst Cu/Zn/Al₂O₃ were employed such as the modification of the synthesis time and the addition of Pd as a dopant agent. The most efficient catalyst among those tested was a palladium-doped catalyst, 5% Pd/Cu/Zn/Al₂O₃. This had a selectivity of 64% at 210 °C and 5 bar.