Ir–Re alloy as a highly active catalyst for the hydrogenolysis of glycerol to 1,3-propanediol

Abstract

We report for the first time the synthesis of a Ir–Re alloy catalyst, which exhibits significantly improved activity in glycerol hydrogenolysis and enhanced resistance against particle sintering compared with a Ir–ReOx structured catalyst.

Ir@Pt bimetallic overlayer catalysts for aqueous phase glycerol hydrodeoxygenation

“…Following impregnation all catalysts were dried in an oven overnight. The iridium parent and the Ir-Pt bimetallic catalyst were calcined in near stagnant air at 500°C for 3 h [21], while pure Pt catalyst was calcined at 400°C for 3 h [17]. The catalysts were then reduced under 60 sccm H 2 flow at calcined temperatures for 3 h.…”

“…The close covalent radius of iridium (1.41 Å) relative to platinum (1.36 Å) [20] is expected to result in a higher platinum coverage of Ir@Pt than Ni@Pt and Co@Pt, due to a lower degree of atomic size mismatch (compared to Pt on Ni or Co). Also, iridium was observed to be selective in catalyzing C-O bond cleavage relative to C-C bond cleavage in producing 1,3-propanediol from glycerol hydrogenolysis [21,22]. Therefore, a platinum overlayer atop iridium is predicted to display higher reactivity and selectivity for the production of renewable fuels from APH compared to pure Pt, as well as result in a relatively high platinum overlayer coverage.…”

Influence of Impregnation Processes on Ruthenium–Molybdenum Carbon Catalysts for Selective Hydrodeoxygenation of Biomass‐Derived Sorbitol into Renewable Alkanes

“…Further calcination treatment would strengthen the interactions between Mo 6 + and support and decrease the reducibility and mobilityo fM os pecies. [18] Thef inal reduction process would reduce the Ru 3 + to Ru 0 and help partially reduce Mo species to form MoO x .O nt he basis of the experimental results and catalyst characterization, this process would ensure the higher coverage ratio of MoO x on the Ru surface or vicinity,w hich would enhance the efficiency of H 2 spillover and interaction between Ru and MoO x .A ccording to the existing literature,t he dehydration of polyol requires high reaction temperature,b ut it favors the CÀCc racking by retroaldol reaction via dehydrogenation of the substrates,e specially in the presence of Ru. [1a,b,4f, 5, 7b,18b] Therefore, our finding is very important to help find an effective methodt op repare effective Ru-MoO x /C catalysts to produce renewable alkanesa nd lowC ÀCc racking products from biomass-derived feedstocks.…”

Hydrogen Doping into MoO3 Supports toward Modulated Metal–Support Interactions and Efficient Furfural Hydrogenation on Iridium Nanocatalysts

“…As shown in Figure c, four peaks can be deconvoluted from the Ir 4f profiles, along with one assigned to Mo 4s at 66.8 eV. The peaks at 61.6 and 64.6 eV were ascribed to 4f 7/2 and 4f 5/2 of Ir δ+ , respectively, and those at 60.8 and 63.8 eV were associated with Ir 0 . On the sample obtained at 200 °C, dominant Ir δ+ and negligible Ir 0 species were observed, which is a result of insufficient reduction at this temperature.…”

“…After a typical impregnation with H 2 IrCl 6 solution, a reduction by using 5 vol % H 2 /Ar at different temperatures (200–600 °C) was conducted to simultaneously generate Ir NPs and H−MoO x supports. Hydrogen temperature‐programmed reduction (H 2 ‐TPR) analysis clearly identified the reduction of Ir 4+ species to metallic Ir on the MoO 3 surface at around 192 °C, and the following hydrogen consumption at 218 °C could be ascribed to the H doping into MoO 3 supports (Figure a) . The easier reduction of MoO 3 at such low temperature, in comparison with that for bare MoO 3 at around 496 °C, can be ascribed to the H 2 spillover from Ir NPs onto the MoO 3 surface.…”