Honeycomb carbon monoliths with different textural properties and surface chemistry were obtained from by stereolithography 3D printing of tannin-based resins. These new, architected materials have shown interesting performance as catalysts for the ozonation of oxalic acid and as catalyst supports for the hydrogenation of bromate ions in solution. They thus highlight the potential of 3D carbons for heterogeneous catalysis as an alternative to macro-structured carbonaceous catalysts.

Abstract

The remediation of polluted water is a major concern for public health and the environment. Catalytic removal of model organic and inorganic pollutants in water using carbon catalysts has shown promising results. In the present work, stereolithographically 3D-printed bio-based carbon monoliths with different textural and surface chemistry properties were used as catalysts for oxalic acid oxidation and catalyst supports for bromate reduction in continuous systems. A significant synergistic effect between ozone or dihydrogen and carbon catalyst was evidenced by mineralization of 14–25 % of oxalic acid or reduction of 15–45 % of bromates in the steady state, respectively. The best results were achieved with samples with the highest mesoporous surface area or, in the case of lower surface area, with samples having the strongest basic character. As materials with great potential, optimizing the textural properties of architected carbon monoliths will enable them to compete with other macro-structured carbon catalysts.