Selective oxidation of glycerol with oxygen in base-free solution over MWCNTs supported PtSb alloy nanoparticles

Promoting role of bismuth on carbon nanotube supported platinum catalysts in aqueous phase aerobic oxidation of benzyl alcohol

“…Furthermore, owing to the positive effect of Bi avoiding Pt from oxidizing, the deactivation of PtBi/CNT (with 2% selectivity and 9% conversion decrease) is much slower than that of Pt/CNT (with 8% selectivity and 39% conversion decrease) after six reaction cycles. PtBi/CNT catalyst was proved as a remarkably effective catalyst with high stability for the aerobic oxidation of benzyl alcohol.Bismuth as an excellent promoter of p-electron metal has attracted extensive attention in heterogeneous catalysis within both fundamental research and industrial applications.Significantly enhanced catalytic performance was obtained on Bi-promoted Pt-or Pd-based catalysts in the selective oxidation of alcohols with molecular oxygen as the oxidant in aqueous solutions [1][2][3][4][5][6][7][8][9]. In the early 1990s, Mallat et al firstly reported the Bi-promoted carbon and alumina supported Pd catalysts with improved conversion and selectivity in the oxidation of 1-methoxy-2-propanol to 1-methoxy-2-propanone [10].…”

Promoting Role of Bismuth on Hydrotalcite-Supported Platinum Catalysts in Aqueous Phase Oxidation of Glycerol to Dihydroxyacetone

“…The selectivity of DHA is comparable to that (ca. 80%) observed on the Pt-Bi supported on carbon-based materials with high BET surface areas [19][20][21][22], in which Bi species were observed in the form of Bi2O2CO3 or Bi2O3 and Bi meal, and the geometric blocking effect of active sites by bismuth adatoms was proposed for the high selectivity of DHA. Owing to the difference in Bi species among the Pt-Bi/HT and Pt-Bi/carbon-based materials, herein, the increase in catalytic activity and selectivity for DHA upon introduction of Bi species could be possibly attributed to the strong hydrogen bond between BiOCl on the surface of HT and glycerol molecule, which enormously enhances the adsorption ability of the catalyst towards glycerol.…”

“…In the case of Pt-Bi-based catalysts used for the selective oxidation of glycerol towards DHA, three chemical states of Bi including Bi (0), Bi2O3, Bi2O2CO3 and BiO(OH) [17][18][19][20] are often found. Various interpretations for the role of promoters, such as the geometric blocking effect of active sites [17,20,33] and the formation of a complex among Pt, Bi, and substrate [34], have been proposed.…”

“…BiOCl could not be completely reduced to zero-valence Bi by NaBH4, as was confirmed by XPS. It should be noted that Bi species generally existed in the form of Bi2O2CO3 or Bi2O3 and Bi (0) meal for Pt-Bi-based catalysts [17][18][19][20], to which the hydrochloric acid was applied to improve the solubility of BiCl3 during the Bi loading process. For Pt-Bi/HT catalysts in our study, the Bi loading procedure was carried out in the absence of hydrochloric acid with BiCl3 as precursor of Bi, that maybe leads to the hydrolysis of BiCl3 to BiOCl.…”

Catalytic Oxidation Pathways for the Production of Carboxylic Acids from Biomass

“…On a Pt/C catalyst, glyceric acid was still the main product (55 % selectivity); but the deposition of bismuth on platinum particles orientates the selectivity toward the oxidation of the secondary hydroxyl group to yield dihydroxyacetone with a selectivity of 50 % at 70 % conversion [ 6 ]. The optimization of the bimetallic Pt-Bi At the same time, dihydroxyacetone was relatively "stable" over the homogenous Pt-Sb alloy nanoparticles, which depressed the cleavage of C-C bond [ 13 ]. Other than Pt catalysts, an Au nanoparticle catalyst was also used for the selective oxidation of glycerol.…”