Preparation, characterization and catalytic performance of high stability of LaCoO 3 @CuO composite with core-shell structure for methanol steam reforming

The CuO modified LaCoO 3 @CuO-x catalysts were prepared through sol-gel method, and applied for methanol steam reforming (MSR). The catalysts were characterized by means of XPS, XRD, SEM, BET, TEM and EDS techniques. XPS and XRD analyses show that the synthesized catalysts are the combination of LaCoO 3 and CuO. The results of XPS also demonstrated that the Co ion in perovskite exhibits a mixed valence state of Co 3+ and Co 2+ , and the presence of Co 2+ contributes to the reduction of Cu 2+ to copper and also promotes the formation of hydrogen. The results of SEM and TEM show that LaCoO 3 @CuO-0.2 catalyst with core-shell type has porous structure, which contributes to expedite the contact between the reaction medium and the catalyst surface, therefore, improving the catalytic performance. The results of the pore size show that LaCoO 3 @CuO-0.2 exhibits remarkably large pores compared with other catalyst samples. The MSR experimental results illustrate that LaCoO 3 @CuO-0.2 has the optimal catalytic performance, and the methanol conversion of LaCoO 3 @CuO-0.2 is 100%. In addition, the stability of LaCoO 3 @CuO-0.2 was evaluated under the optimum operating parameters (the catalytic temperature, LHSV and W/M are 873 K, 20 h −1 and 4:1, respectively). The results show that the developed LaCoO 3 @CuO-0.2 has excellent stability within 50 h without deactivation. Graphical abstract The LaCoO 3 @CuO-0.2 developed in this study with core-shell structure has outstanding catalytic performance and excellent stability. The presence of Co 2+ proves the existence of oxygen vacancies on the surface of the catalyst, which is helpful for the reduction of Cu 2+ to copper and promotes the MSR reaction.