Surface enrichment of lanthanum on Co3O4 for stable chemical looping combustion

This study introduced a durable oxygen carrier with surface enrichment of lanthanum on Co3O4 for chemical looping combustion. It employed the surface enrichment in order to optimize the usage of rare earth lanthanum with secured stability of oxygen carriers. The formation of LaCoO3 perovskite on the Co3O4 surface imparts strong durability and overcomes deactivation of Co3O4 while maintaining CO2 selectivity due to its enhanced sintering resistance. Lanthanum dopants were optimized at 10 wt%. Co3O4 with 10 wt% of lanthanum had 93.1% and 95.4% average CO2 selectivity and CH4 conversion at 800 °C for 50 cycles, respectively. The surface enrichment provides not only resistance to sintering but also high oxygen storage capacity for long-term cyclic chemical looping combustion. [Display omitted] •Surface-enriched La on Co3O4 is introduced to obtain the durable oxygen carrier (OC).•Enhanced stability of OC in CLC is attributed to the optimized amount of La.•Trade-off exists between thermal stability and reaction activity according to La amount.•10 wt% of La on Co3O4 has stability with high CH4 conversion and CO2 selectivity.