Calcination temperature as a key lever for product selectivity in CO2 hydrogenation to methanol over Re/TiO2

• The calcination of the Re/TiO₂ catalyst enhance methanol selectivity from 53% to 73%. • Calcination generates smaller Re clusters, which are crucial for high methanol selectivity. • In situ synchrotron XRD and Raman reveal that calcination decomposes the NH₄ReO₄ precursor into ReOx species. • The presence of a rutile phase in the TiO₂ support is shown to be detrimental to methanol synthesis from CO₂. • The optimized Re/TiO₂ catalyst achieves a rate of methanol of 16 mol·mol Re ⁻¹ ·h⁻¹ at 200 °C and 100 bar.