Engineering non-noble Ni/WOx-ZrO2 towards boosted fuels production by catalytic upcycling of polyethylene at mild conditions.

Moderate WO x surface density of Ni/WO x -ZrO 2 with higher Brønsted/Lewis acid sites ratio enhances LDPE hydrocracking and obtains the maximum liquid yield. [Display omitted] • The non-noble Ni catalysts achieves the LDPE hydrocracking process under a mild condition. • The Ni/WO x -Zr catalysts achieves 100 % LDPE conversion with 76.9 % liquid yield. • The WO x surface density shows a volcanic-shape relationship with the B/L ratio of catalyst. • The LDPE hydrocracking performance has a linear relationship with the B/L ratio of catalyst. Chemical upcycling through catalytic hydrocracking to fuels has potential to mitigate the serious environmental issues caused by plastic waste. Herein, non-noble tungstate-zirconia supported nickel catalyst (Ni/WO x -ZrO 2) with tunable Brønsted/Lewis (B/L) ratio was firstly proposed for the hydrocracking of low-density polyethylene (LDPE), which achieves hydrogenation/dehydrogenation on Ni sites and cracking/isomerization on WO x -ZrO 2 , respectively. Excellent 100 % LDPE conversion with 76.9 % liquid yield was achieved, which is comparable to noble Ru-based and Pt-based catalysts. Quantitative linear relationship between B/L ratio and hydrocracking performance was established, and the key to boost performance was keenly controlling the volcanic-shape relationship between surface WO x density and B/L ratio of catalyst. Moderate WO x surface density with higher B/L ratio enhances LDPE hydrocracking, and inhibits the hydrogenation of the primary products. However, excessive WO x polymerized and formed WO 3 crystals, compensating acid sites and inhibiting LDPE hydrocracking. This work is of prime scientific and industrial significance to the rational design of catalysts for industrial plastic hydrocracking. [ABSTRACT FROM AUTHOR]