Comparative life cycle assessment of Ni-based catalyst synthesis processes

Ni-based catalysts supported on ceramics are particularly suitable for industrial applications, for instance reforming of hydrocarbons to produce synthesis gas or hydrogen and production of carbon nanofibers. Conventional synthesis processes for all metal/ceramic catalysts are impregnation, precipitation, co-precipitation and others. The authors have previously developed a novel process for the synthesis of Ni-based catalysts supported on reticulated ceramic foams, including impregnation of foams with ultrasonically generated aerosols of dissolved metal chlorides. By using appropriate multi-criteria analysis methods, the authors concluded that the novel process for the synthesis of Ni-based catalysts was superior in terms of economic and technological aspects. The aim of this research was to compare the novel synthesis processes for a Ni-Pd/Al2O3 catalyst and for other Ni-based catalysts by performing life cycle assessment and evaluating the environmental impacts of each synthesis process. Characterisation results showed that the dominant environmental impact results from production of palladium (II) chloride for the Ni-Pd/Al2O3 catalyst synthesis process, while the other catalyst synthesis process had large environmental impacts associated with high energy consumption. The final outcome, obtained from comparison of normalisation results, indicates that the novel Ni-Pd/Al2O3 catalyst synthesis process had the smallest environmental impact.