Control of Ni/Ce1-xMxOy catalyst properties via the selection of dopant M = Gd, La, Mg Part 1. Physicochemical characteristics

Abstract

To elucidate the role of support composition in autothermal reforming of ethanol (ATR of C₂H₅OH), a series of Ni catalysts (Ni content 2–15 wt.%) supported on different ceria-based oxides (Ce_1-xGd_xO_y, Ce_1-xLa_xO_y and Ce_1-xMg_xO_y; x = 0.1–0.9) were prepared. The synthetized materials were tested in ATR of ethanol at 200–700 °C. It was established that supports themselves show catalytic activity in ATR of C2H5OH and provide 10–15% yield of H₂ at 700 °C. Upon the increase of Ni content from 2 to 15 wt.% the temperature of 100% ethanol conversion decreases from 700 tо 300 °С, hydrogen yield increases from 25 to 60%, the inhibition of С₂-С₃ by-products formation, as well as the promotion of decomposition of acetaldehyde occur. The enhancement of catalyst performance in ATR of C₂H₅OH has been observed in the next series of supports: Ce_1-xMg_xO_y < Ce_1-xGd_xO_y < Ce_1-xLa_xO_y and with a decrease of x to an optimal value that correlates with the improvement of Ni active component reducibility. At 600 °C on 10Ni/Ce_0.8La_0.2O_1.9 catalyst the H₂ yield of 50% was achieved at C₂H₅OH conversion of 100%. Stable and high performance of developed catalysts in ATR of C₂H₅OH indicates the promise of their use in the production of hydrogen.