Exploiting oxidative coupling of methane performed over La(CeMg)O catalysts with disordered defective cubic fluorite structure

• Published in: Catalysis science & technology 2021-07, Vol.11 (13), p.4471-4481
• Main Authors: Petrolini, Davi D, Marcos, Francielle F. C, Lucrédio, Alessandra F, Mastelaro, Valmor R, Assaf, José M, Assaf, Elisabete M
• Format: Article
• ISSN: 2044-4753; 2044-4761
• DOI: 10.1039/d1cy00187f

The oxidative coupling of methane reaction to produce C 2 compounds was studied using La 2 (Ce 1− x Mg x ) 2 O 7− δ catalysts with disordered defective cubic fluorite structures, varying the Mg content (0.0 ≤ x ≤ 1.0), CH 4 /O 2 ratio, temperature, and WHSV. The partial substitution of Ce by Mg in the structure modified the morphology, adjusted the reducibility, stabilized the Ce 3+ species, and provided different concentrations of basic sites, which allowed a 42% increase in the yield of C 2 , with ethylene as the major product. The catalyst with 0.4 Mg content in the structure provided C 2 selectivity of 52%, with CH 4 conversion of 28%, even under conditions richer in O 2 . The highest selectivity to C 2 (75%), with the highest selectivity to ethylene (39.1%), was achieved using a CH 4  : O 2 ratio of 8 : 1. In addition, it was possible to operate at milder temperatures (650 °C), with satisfactory CH 4 conversion (22%) and C 2 selectivity (54%). By decreasing the space velocity, the CH 4 conversion and C 2 selectivity decreased with an ethylene/ethane ratio of 3. The inhibitory effects of H 2 O and CO 2 were observed at lower space velocity. The oxidative coupling of methane reaction to produce C 2 compounds was studied using La 2 (Ce 1− x Mg x ) 2 O 7− δ catalysts with disordered defective cubic fluorite structures, varying the Mg content (0.0 ≤ x ≤ 1.0), CH 4 /O 2 ratio, temperature, and WHSV.