Controlling the selectivity of the hydrogenolysis of polyamides catalysed by ceria-supported metal nanoparticles.

Wu, XinBang; Lee, Wei-Tse; Turnell-Ritson, Roland C; Delannoi, Pauline C L; Lin, Kun-Han; Dyson, Paul J · Nat Commun · 2023

basic_science · Level V

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Abstract

Catalytic hydrogenolysis is a promising approach to transform waste plastic into valuable chemicals. However, the transformation of N-containing polymers, such as polyamides (i.e. nylon), remains under-investigated, particularly by heterogeneous catalysis. Here, we demonstrate the hydrogenolysis of various polyamides catalysed by platinum-group metal nanoparticles supported on CeO<sub>2</sub>. Ru/CeO<sub>2</sub> and Pt/CeO<sub>2</sub> are both highly active but display different selectivity; Ru/CeO<sub>2</sub> is selective for the conversion of all polyamides into water, ammonia, and methane, whereas Pt/CeO<sub>2</sub> yields hydrocarbons retaining the carbon backbone of the parent polyamide. Density functional theory computations illustrate that Pt nanoparticles require higher activation energy for carbon-carbon bond cleavage than Ru nanoparticles, rationalising the observed selectivity. The high activity and product selectivity of both catalysts was maintained when converting real-world polyamide products, such as fishing net. This study provides a mechanistic basis for heterogeneously catalysed polyamide hydrogenolysis, and a new approach to the valorisation of polyamide containing waste.