Au–Pd/C catalysts for glyoxal and glucose selective oxidations

Molybdenum Oxoanions as Dispersing Agents in the Preparation of Pd/C Catalysts for the Selective Oxidation of Glyoxal

“…The results obtained were by far better than with reference monometallic Pd/C catalysts (Table 1), and compared very well with bimetallic Bi-Pd/C catalysts, whose performance were reported earlier [44][45][46]. The results obtained here are similar to Pd/C catalysts prepared by the optimized adsorption method [28], but obviously not as good (at t = 20 h) as the Au-promoted optimized Pd/C systems [29,30]. A Pd-free catalyst prepared following the same procedure, but introducing only the Mo precursor, was checked to be completely inactive (Y AGLY \ 1%).…”

“…By contrast with previously reported results with Bi-Pd/C catalysts, where it had been identified at 24 h [45], the maximum yield in glyoxalic acid is here not yet attained after 48 h, but it is still in constant augmentation. The yield in glyoxalic acid obtained (after 48 h) is thus superior (or equal) to all former results obtained so far with the best catalysts for this reaction [28][29][30][44][45][46][47][48]. This is particularly obvious when comparing the yields in glyoxalic acid normalized with respect to the amount of active metal (Pd) [28][29][30][44][45][46][47][48], Table 2.…”

“…In consequence, we have been looking for alternative promoters for this reaction, which would not leach, but maintain the required high selectivity and activity. Ruthenium and gold were found to be promising candidates [29,30,47,48], but the former had a mitigate action that seemed to be highly dependent on the preparation procedure, while the latter did not solve the economical constraint.…”

“…We have shown that the so-called 'Strong Electrostatic Absorption' (SEA) method developed by Regalbuto et al [27] has its limits for depositing Pd(II) on carbon, because the large pH-window for maximum surface absorption corresponds to the existence of neutral Pd species in solution, thus precluding an electrostatic mechanism from taking place [28][29][30]. The goal of the present study is to take advantage of the charged nature of Mo POMs to interact electrostatically with the surface and serve as intermediate for the adsorption of Pd on carbon, for catalytic application in glyoxal selective oxidation.…”

Preparation and catalytic properties of composites with palladium nanoparticles and poly(methacrylic acid) microspheres

“…Especially, they have outstanding catalyst activity in many organic reactions such as deoxygenation of fatty acids [8], Heck reaction [9], formic acid electro-oxidation [10], and selective oxidation of organic compounds [11]. In most reactions, the catalysts are homogeneous nanoparticles complexed by ligands including carbene, phosphine, amine, and dibenzylidene acetone.…”