Trimetallic catalyst

The activity results clearly indicate that both Sn and Re significantly improves the activity of platinum in the hydrogenolysis of AcOBu. As seen in Figure 4 the specific activity (rSn+Re, mol/molpr0moterxh) of trimetallic catalysts has a maximum in the function of promoter concentration (Sn+Re) at 70 mmol/goataiyst (0.75 wt. % Re). 

Figure 5 shows the specific reaction rate has a maximum at Re/(Re+Sn+Pt) concentration ratio of 0.5. The trimetallic catalysts at concentration ratio of 0.4-0.6 are almost twice as active than the 0.3Sn0.3Pt(b) catalyst and the... 

Trimetallic catalysts try to combine the individual advantages in a single system. However, there are controversial positions on whether they are more cost-effective than the use of stacked-bed reactors. Several formulations are offered in the market CoNiMo, CoNiW, and NiMoW, so far they are seldom employed. 

The SECM capacity for rapid screening of an array of catalyst spots makes it a valuable tool for studies of electrocatalysts. This technique was used to screen the arrays of bimetallic or trimetallic catalyst spots with different compositions on a GC support in search of inexpensive and efficient electrocatalytic materials for polymer electrolyte membrane fuel cells (PEMFC) [126]. Each spot contained some binary or ternary combination of Pd, Au, Ag, and Co deposited on a glassy carbon substrate. The electrocatalytic activity of these materials for the ORR in acidic media (0.5 M H2S04) was examined using SECM in a rapidimaging mode. The SECM tip was scanned in the x—y plane over the substrate surface while electrogenerating 02 from H20 at constant current. By scanning... 

Hydrotreated naphthas (combined) were then reformed over a 0.6% Pt on A1203 catalyst at 500°C, 500 psig, 3 LHSV, and 5 M scf H2/bbl. This simple catalyst was chosen in preference to the more advanced bi- and trimetallic catalysts because of its probably lower sensitivity to heteroatom poisoning. The reformates were analyzed by gas chromatography... 

The reductive homocoupling of chlorobenzene to biphenyl is efficiently catalyzed by a recyclable, heterogeneous trimetallic catalyst in the presence of PEG 400 in H2O (Scheme 14.81) [164]. Bismuth is believed to trap the surplus hydrides and retard undesired side-reactions. A ternary metal redox system, BiCl3-Al-NiCl2(bpy), mediates the reductive coupling of /flirornoslyrene [165]. 

Chloro- or bromoarenes undergo an Ullmann-like reductive homocoupling to the respective biphenyls in the presence of PEG-400 (PT catalyst) and a trimetallic catalyst consisting of 4% Pd, 1% Pt, and 5% Bi on carbon with either hydrogen, formate and water, or zinc and water. Simple dehalogenation, a side reaction, can be minimized (Eq. 5). 

A trimetallic catalyst of Ba/Mg/Al used in the synthesis of HTSBR will be described and its living polymerization characteristics will be considered in some detail. Copolymerization reactivity ratios and styrene sequence distribution of HTSBRs will be compared with emulsion SBRs. This section will conclude with the crystallization behaviour of HTSBRs. Technological properties will be discussed in Sections 4.6 and 4.7. 

There has been a wide interest in the biomimetic hydrolytic activity of bimetallic and trimetallic catalysts [5], In the frame of this research line, caUxarenes have been extensively used as molecular scaffolds to connect ligands for metal cations. 

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