Intrinsic activity of interfacial sites for Pt-Fe and Pt-Mo catalysts in the hydrogenation of carbonyl groups

On‐the‐fly Catalyst Modification: Strategy to Improve Catalytic Processes Selectivity and Understanding

“…On‐the‐fly modification entails modification of catalyst metal surface by dopant(s) followed by the catalytic reaction that quantifies the effect of the modification. Nevertheless, we think methods such as atomic layer deposition (ALD), controlled surface reactions (CSR), and galvanic displacement can be easily adapted to performed similar on‐the‐fly modifications.…”

Valorization of Biomass‐derived Small Oxygenates: Kinetics, Mechanisms and Site Requirements of H2‐involved Hydrogenation and Deoxygenation Pathways over Heterogeneous Catalysts

“…The last point to note in regard to the support effect is that bifunctional catalysts comprised of metal particles and metal oxides (or zeolites) with strong Brønsted acidity have been found in many reports to offer greatly enhanced activity in HDO reactions; for example, in the case of acetone hydrogenation, Pt/H‐ZSM‐5 was found to be an order of magnitude more active than Pt/SiO 2 containing similarly sized Pt particles . This rate enhancement appears similar in magnitude as that observed with Pt‐FeO x and Pt‐MoO x catalysts, though it remains to be understood as to whether these effects share the same mechanistic origins.…”

“…In another contribution, the turnover rate of propanal hydrogenation (in batch and flow reactors) on a γ‐Al 2 O 3 ‐supported Ni−Pt catalyst was shown to be a factor of 5 greater than monometallic Pt and Ni, with the latter two exhibiting nearly identical activities . Similarly, the TOF (interfacial sites quantified by CO chemisorption) of acetone hydrogenation at 353 K and ambient pressure over Pt 1 Fe x /SiO 2 (x, atomic Fe/Pt ratio, varying between 0.025 and 0.2) prepared by controlled surface reaction were higher by 5–70 times than that over Pt/SiO 2 alone or a physical mixture of Pt/SiO 2 and Fe 0.2 /SiO 2 . For the same reaction, these authors found that similarly synthesized Pt 1 Mo x /SiO 2 (x=0.15, 0.30 and 0.45) catalysts were two orders of magnitude more active than Pt/SiO 2 alone and a physical mixture of Pt/SiO 2 and Mo 0.3 /SiO 2 .…”

“…Recent works on liquid‐phase hydrogenation of small aldehydes and ketones concern primarily bimetallic catalysts, with the majority of examples being based on a combination of Pt and a more oxophilic metal such as Mo, Fe, Ru, Ni and Ag –,. A better hydrogenation performance of bimetallic catalysts compared to the individual monometallic counterparts, in terms of both activity and selectivity to alcohol products without carbon losses and over‐hydrogenation, is usually observed.…”

“…On the other hand, oxidative treatment in O 2 /N 2 at room temperature for extended durations (48 and 96 h) increased the fraction of surface RuO x species, i. e., additional sites for C=O activation, without destroying the Pt−Ru alloy structure and changing the mean size of these alloy domains, thereby resulting in further rate enhancements. In the case of Fe, which usually is present in multiple phases and oxidation states, it has been noted that the promotional effect on the hydrogenation rate is greater for an aldehyde than a ketone ,…”