Interplay between Copper Nanoparticle Size and Oxygen Vacancy on Mg-Doped Ceria Controls Partial Hydrogenation Performance and Stability

A series of CunCeMgOx catalysts with various copper nanoparticle sizes and surface defect densities were synthesized and tested for partial hydrogenation of 1,3-butadiene (1,3-BD). The data demonstrated a reaction pathway involving the dissociation of molecular hydrogen on the peripheral oxygen vacancies (O-v-Cu+) before reacting with 1,3-BD adsorbed on the corresponding Cu+ atoms. Analysis of the performance data indicated that the turnover frequency of these Cu+ sites is approximately five times higher than those of the surface Cu-0 sites. Among the catalysts considered, Cu0.5CeMgOx with the smallest copper nanoparticle size provided a stable performance for at least 15 h time-on-stream, while the others were easily deactivating because of carbon deposition. Furthermore, unlike the conventional copper-based catalysts, the Cu0.3CeMgOx catalyst achieved a complete suppression of total hydrogenation even at space velocities offering a complete 1,3-BD conversion. The findings offer a broad potential for the rational design of noble metal-free, highly selective, and stable copper-based partial hydrogenation catalysts for reactions that are prone to coke formation.

Automated summary

The study found that the Cu0.5CeMgOx catalyst showed the most stable performance, while the Cu0.3CeMgOx catalyst achieved complete 1,3-BD conversion with complete suppression of total hydrogenation. These findings offer new possibilities for designing noble metal-free, highly selective, and stable copper-based catalysts.