Precious or Base Metals? A Sustainability Assessment of Catalytic Strategies in Chemical Synthesis

The widespread use of precious-metal catalysts has enabled highly efficient fine chemical syntheses but has also intensified concerns over critical raw material dependence, catalyst cost, and the environmental burdens associated with their production. Although catalyst recycling and substitution with base metals are increasingly proposed as circularity strategies, their economic and environmental trade-offs have rarely been evaluated at the process level. Here, we develop an integrated techno-economic assessment (TEA) and life-cycle assessment (LCA) framework to compare three catalyst-management strategies: conventional precious-metal catalysis, precious-metal catalysis with catalyst recycling through organic solvent nanofiltration, and base-metal catalysts. Five industrially relevant fine chemical syntheses encompassing pharmaceutical active ingredients and high-value intermediates were selected as representative case studies. Catalyst recycling reduced catalyst demand while requiring only a moderate increase in capital expenditure and lowering operating costs and environmental impacts relative to conventional precious-metal catalysis. Base-metal substitution delivered the largest overall improvements, decreasing average capital expenditure by ca. 8%, operating costs by up to 28%, and carbon emissions by 25%, mitigating planetary-boundary and endpoint environmental impacts. Thus, base-metal catalyst substitution emerged as the preferred long-term strategy for advancing catalyst circularity. Importantly, sensitivity analysis identified catalytic performance as a decisive design parameter: base-metal substitution remained advantageous when catalytic activity is maintained within approximately 15% of the precious-metal benchmark, whereas larger activity losses could shift the preferred strategy toward recycling the precious-metal catalyst. These results establish a process-level framework for catalyst circularity and show that recycling and base-metal substitution are complementary rather than competing strategies.