Sponge-like carbon monoliths: Porosity control of 3D-printed carbon supports and its influence on the catalytic performance

Sponge-like carbon monoliths with tailored channel architecture and porosity were prepared by combining sol-gel polymerization and 3D printing technology. The pore size distribution (PSD) and macropore volume were controlled by varying the water concentration used in the synthesis. The size and interconnection degree of primary particles, and consequently the pore width and macropores volume, increases by increasing the water concentration. However, a more heterogeneous PSD was detected at high water concentration, due to the better defined spheres-like morphology of primary particles which leaves voids and corners between fused spheres together with bigger macropores leaves by the coral-like structure. The role of this porosity control on the CuO/CeO2 catalytic performance was pointed out in the CO-PrOx reaction. The CuO/CeO2 dispersion and distribution along the carbon network increases by increasing the water concentration, i.e. the pore width and macropore volume, enhancing the catalytic activity. However, this improvement is not observed at high water concentration in which preferential flow pathways are created favored by the heterogeneous PSD. This manifest that the porosity control plays an important role in the catalytic performance of monolithic catalysts and thus, the monolithic support must be specifically designed to optimize the catalytic performance of active phases for each application.

Automated summary

Sponge-like carbon monoliths with tailored channel architecture and porosity were prepared using sol-gel polymerization and 3D printing technology. The size and interconnection degree of primary particles, pore width, and macropores volume can be controlled by varying the water concentration used in the synthesis. Higher water concentration enhances the dispersion and distribution of CuO/CeO2 on the carbon network, increasing catalytic activity. However, a more heterogeneous pore size distribution at high water concentration leads to preferential flow pathways and hinders the improvement in catalytic performance.