Exceptional control of carbon-supported transition metal nanoparticles using metal-organic frameworks

Synthesis of Zn-MOF incorporating titanium-hydrides as active sites binding H2 molecules

“…This was in contrast to HCC-1/Ti(Cy) 3 showing the amount of the Ti species as 3.5 wt. %, thereby validating the successful PSM, as suggested previously [12,[16][17][18].…”

“…In addition, the bulk crystal phases of HCC-1 was also retained after the PSM, as demonstrated by the XRD pattern of HCC-1/Ti(Cy) 3 showing the diffracted peaks located at almost identical position as that of the parent HCC-1 (Fig. 2b) [12,[16][17][18]. The decrease in the intensity of peaks, however, was observed in HCC-1/Ti(Cy) 3 , as compared with that of the parent HCC-1, which is likely due to the geometrical dependency of Zn-MOFs on the kind and the presence of guest molecules (i.e., Ti(Cy) 3 ) occupying its pores [33,34].…”

“…This occupation was also evidenced by the N 2 physisorption of this intermediate (HCC-1/Ti(Cy) 3 ) showing the decreased value of S BET as 2160 m 2 g -1 after the PSM. This was due in part to the presence of the Ti species inside the mesopores of HCC-1, thereby limiting the accessibility of N 2 molecules [12,[16][17][18]. Most importantly, to further demonstrate the coordination of Ti(Cy) 3 to -OH functionality innate to HCC-1, we employed IRMOF-16 as a control material since this Zn-MOF is iso-structural to HCC-1 except it does not impart -OH functionality [13].…”

“…This renders the use of Zn-MOFs as reactive supports since these functionalities were post-synthetically modified using organic/inorganic precursors to provide properties beneficial for the target applications [16,17]. Notably, the ability of these Zn-MOFs site-isolating active metal sites [1,16,18] suggested their usage as adsorbents interacting with H 2 molecules via Kubas-type interaction [19,20]. This interaction is defined as a chain reaction through an electron donation from an σ-orbital of H 2 to an empty d-orbital of transition metal and the subsequent electron back donation from the d-orbital of transition metal to an empty σ * -orbital of H 2 , where transition metal can be Ti, V, and Sc [21].…”

In Situ Formation of Metal Carbide Catalysts

“…It is also observed that molybdenum oxide biomass catalysts must first undergo carburization before conversion occurs . Some research indicates that it may be the combination of the oxide and carbide forms of the metal catalysts that most efficiently react with the biomass . Many reaction pathways also specify that surface carbon plays a role in the formation of final products.…”