A series of Pd−WO x /Al 2 O 3 catalysts with different contents of WO x were prepared by stepwise incipient wetness impregnations. The influence of WO x on the physicochemical properties of Pd−WO x /Al 2 O 3 catalysts, as well as their catalytic performance for the hydrogenolysis of glucose to 1,2-propanediol (1,2-PDO), was investigated. At low surface W density (0.3−2.1 W nm −2 ), distorted isolated WO x and oligomeric WO x are present on the Pd−WO x /Al 2 O 3 catalysts. Furthermore, isolated WO 4 are the dominating species on the Pd−WO x (5%)/Al 2 O 3 catalyst. When the W density increased to 3.1 W nm −2 , polymeric WO x species are dominant on the Pd−WO x (30%)/Al 2 O 3 catalyst. The Pd surface area decreased while the acid amount increased with increasing W density. Furthermore, increased Lewis acid sites are provided by isolated WO 4 and oligomeric WO x species whereas increased Brønsted acid sites exist on polymeric WO x species. Lewis acid sites promote glucose isomerization to fructose, which is an intermediate in glucose hydrogenolysis to 1,2-PDO. Metal sites catalyze CO hydrogenation and C−C hydrogenolysis, which avoid the coke formation on catalysts. 1,2-PDO selectivity is dependent on the synergy of Lewis acid and metal sites; however, Brønsted acid sites have no contribution to the 1,2-PDO production. Typically, the Pd−WO x (5%)/Al 2 O 3 catalyst possessing the optimal balance of Lewis acid and the metal site shows a 1,2-PDO selectivity of 60.8% at a glucose conversion of 92.2% and has a lifetime of over 200 h.

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A synergistic effect normally exists in bimetallic catalysts, which can greatly improve the catalytic performance in comparison with monometallic catalysts. However, the N-doped carbon-supported bimetallic catalysts, especially for noblebased bimetallic catalysts prepared by one-pot pyrolysis at high temperatures are scarcely reported. Herein, a novel sustainable Ru−MoO x bimetallic catalyst was successfully prepared by one-pot pyrolysis of biowaste (chitin) and metal salts, which exhibited great improvement in catalytic activity and could be stable up to 5 cycles for the direct hydrogenation of furfural (FAL) to tetrahydrofurfuryl alcohol (THFA). On the basis of series of catalyst characterizations, it was found that there was a strong interaction between Ru and MoO x particles, behaving as the main contributor to the enhanced catalytic performance.