An up-and-coming youngster engaged in collagen modification: Zirconium halide perovskite nanocrystals as chromium-free tanning agent.

Green and sustainable approach is crucial for current and future leather industry. Chrome tanning agents have always been considered as the key materials for turning raw hides into leather by crosslinking collagen fiber. However, the low utilization rate (60-70 %) and potential risks of Cr3+ oxidation to Cr6+ in chromium may make it a past celebrity. In this research, Cs2ZrCl6 nanocrystals (NCs) were applied in tanning process. Zirconium ions integrating with organic ligands in Cs2ZrCl6 NCs allow for a born self-masking structure to give the uniform distribution of Zr4+ form the fresh side to grain side in crust leather with the shrinkage temperature (Ts) of 72.8 °C. Cs2ZrCl6 NCs tanning not only improved the thermal properties, the physical-mechanical and organoleptic properties of tanned leather but also ideal environmental impact assessments. All the effort was devoted to promoting the development of collagen modification and opening up new perspectives on the research of halide perovskites.