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Catalytic conversion of polyolefins to value-added products offers an alternative route to capture value from plastic waste. Here we initially examine reactions of a polyethylene model (hexatriacontane, C36H74) on a Pt/SiO2 catalyst under typical hydrogenolysis and hydrocracking temperatures, which leads to irreversibly adsorbed surface hydrocarbons identified after extraction of hexatriacontane with excess hot toluene. The IR spectra of these catalysts after extraction reveal only aliphatic C–H stretches. SiO2 alone leads similar hydrocarbon adsorption on the surface where extended extraction fails to fully remove the adsorbed hydrocarbons from neat silica. The amount of hydrocarbon irreversibly adsorbed increases nearly 10-fold when the reactant is changed from hexatriacontane to polyethylene (Mn = 4000 Da), but the adsorbed quantity is insensitive to reaction temperature (200–300 °C). These results demonstrate significant, nonextractable hydrocarbon deposition on catalyst support surfaces without dehydrogenation catalyst present at temperatures typical of catalytic deconstruction of polyolefin waste, which may limit catalyst turnover and impact the product distribution. 

Abstract Let $$G$$ be a connected semisimple real algebraic group. For a Zariski dense Anosov subgroup $$\Gamma <G$$, we show that a $$\Gamma $$-conformal measure is supported on the limit set of $$\Gamma $$ if and only if its dimension is $$\Gamma $$-critical. This implies the uniqueness of a $$\Gamma $$-conformal measure for each critical dimension, answering the question posed in our earlier paper with Edwards [13]. We obtain this by proving a higher rank analogue of the Hopf–Tsuji–Sullivan dichotomy for the maximal diagonal action. Other applications include an analogue of the Ahlfors measure conjecture for Anosov subgroups. 

We present a quantitative isolation property of the lifts of properly immersed geodesic planes in the frame bundle of a geometrically finite hyperbolic $$3$$ -manifold. Our estimates are polynomials in the tight areas and Bowen–Margulis–Sullivan densities of geodesic planes, with degree given by the modified critical exponents.