Maximizing the safety and sustainability of MXenes.

Safe and Sustainable by Design (SSbD) is a new regulatory concept guiding chemical and material innovation. The European Commission has recommended a two-stage SSbD framework and plan to revise it based on stakeholder feedback. The framework involves establishing key (re)design SSbD principles and assessment of the final innovation, however the applicability of the framework to advanced materials remains to be addressed. Here, we applied the SSbD framework on TiCT MXenes, an emerging advanced material, by (1) reviewing health, environmental and safety information; (2) characterizing MXenes transformation/dissolution in different media; (3) conducting (eco)toxicological experiments, and (4) completing a prospective life-cycle assessment. Our analysis suggests that TiCT is safe and sustainable when applying the SSbD framework. Further research is needed regarding long-term hazardous effects of TiCT and the sustainable production of the titanium precursor. Guidance is also needed on how much weight one should assign to the different lines of evidence in the overall SSbD assessment.