Unraveling the Dependence of Critical Active Sites of WO_x on Rh/WO_x Catalysts in Tetrahydrofurfuryl Alcohol Hydrogenolysis

Taking the background of the ambiguous role of oxophilic metal oxide in metal-acid bifunctional catalysts for the important field of tetrahydrofurfuryl alcohol (THFA) hydrogenolysis, a linear relationship between the W═O/W-OH content in sub-nano-Rh-supported WO_x and 1,5-pentanediol (1,5-PeD) yields from THFA hydrogenolysis has been established. It reveals that the higher reduction temperature promotes the surface Rh/W ratio. Thus, hydrogen spillover is facilitated, leading to more surface W═O structures and thereby more in-situ-reduced W-OH generation. W-OH structures work as the active sites to provide in situ Brønsted acid, resulting in enhanced selective activation for secondary C-O bonds of THFA. This discovery reveals the unique role of the surface structure on oxophilic metal oxide in chemoselective hydrogenolysis of the secondary C-O bond in polyols.