CO hydrogenation to methanol on Cu–Ni catalysts: Theory and experiment

We present density functional theory (DFT) calculations for CO hydrogenation on different transition metal surfaces. Based on the calculations, trends are established over the different monometallic surfaces, and scaling relations of adsorbates and transition states that link their energies to only two descriptors, the carbon oxygen binding energies, are constructed. A micro-kinetic model of CO hydrogenation is developed and a volcano-shaped relation based on the two descriptors is obtained for methanol synthesis. A large number of bimetallic alloys with respect to the two descriptors are screened, and CuNi alloys of different surface composition are identified as potential candidates. These alloys, proposed by the theoretical predictions, are prepared using an incipient wetness impregnation method and tested in a high-pressure fixed-bed reactor at 100bar and 250–300°C. The activity based on surface area of the active material is comparable to that of the industrially used Cu/ZnO/Al₂O₃ catalyst. We employ a range of characterization tools such as inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis, in situ X-ray diffraction (XRD) and in situ transmission electron microscope (TEM) to identify the structure of the catalysts.