Biomass has attracted much attention as a carbon-neutral resource with the potential to reduce both the rapid consumption of fossil fuels and the vast quantity of CO 2 emissions associated to that consumption. [1] Recent increases in the demand for biodiesel as an alternative fuel have also led to the production of large quantities of glycerol, which is generated as a byproduct of the biodiesel manufacturing process. For this reason, there is currently much interest in developing methods for the chemical transformation of this abundant feedstock into value-added chemicals. Among these methods, [2][3][4][5] the hydrogenolysis of glycerol to 1,3-propanediol (1,3-PDO) is one of the most promising transformations because 1,3-PDO is a useful building block in the production of a wide range of valuable polymers. [6] The production of 1,3-PDO from glycerol has the potential to serve as a viable alternative to the current industrial-scale production of 1,3-PDO from petroleum feedstocks. Many research groups have explored efficient catalytic systems for the selective hydrogenolysis of glycerol to 1,3-PDO. [3] The best system reported to date was developed by Tomishige and co-workers, who described how SiO 2 -supported Ir-ReOx nanoparticles (NPs) produce high yields of 1,3-PDO in aqueous reaction solutions. [3j] Lee and co-workers have also reported the selective synthesis of 1,3-PDO, using sulfated ZrO 2supported platinum NPs, employing 1,3-dimethyl-2-imidazolidinone as solvent. [3d] However, these catalytic systems produced insufficient yields of 56 %, and still required the use of acidic additives and/or organic solvents, and so the development of more efficient catalytic systems for the selective conversion of glycerol to 1,3-PDO remains a challenge.Recently, our group developed a reusable Pt-AlOx/WO 3 catalyst for the selective hydrogenolysis of glycerol to 1,3-PDO in water, [7] with yields greater than those previously reported for organic-solvent-and additive-free catalyst systems. The AlOx plays a crucial role in this selective synthesis of 1,3-PDO because it preferentially combines with the primary OH groups of glycerol to form Al-alkoxides. This allows the subsequent selective hydrogenolysis of the unbound secondary OH group of the glycerol by Pt NPs supported on the WOx, leading to the synthesis of 1,3-PDO. This finding inspired us to design a new catalyst consisting of monohydroxy aluminum oxide (boehmite; AlOOH), which has numerous Al-OH groups on its surface, as a support for Pt NPs and WOx species. Our hypothesis was that the many Al-OH groups of the boehmite support would promote the formation of Al-alkoxide species from the primary OH groups of glycerol, leading to the highly efficient and selective synthesis of 1,3-PDO.Herein, we report that the newly synthesized boehmite-supported Pt NPs/WOx material (Pt/WOx/AlOOH) does indeed act as a highly efficient catalyst for the selective hydrogenolysis of glycerol to 1,3-PDO in aqueous solution without the use of additives. The catalytic activity is superior t...