Promoted chemoselective crotonaldehyde hydrogenation on zirconia-doped SiO2 supported Ag catalysts: Interfacial catalysis over ternary Ag–ZrO2–SiO2 interfaces

Highly Selective Catalysts for the Hydrogenation of Unsaturated Aldehydes: A Review

“…Several methods have been developed to enhance the synergetic effect between the metal and MO x . One method is to use additives, such as zirconia, to modify the MO x . ,, Ruppert and Paryjczak reported that zirconia inhibited the excessive migration of TiO x onto the Pt surface; thus, more metal-MO x interfacial sites were generated for the hydrogenation of CO and thereby higher selectivity and hydrogenation activity were obtained. The catalyst preparation method also affected the synergetic effect.…”

“…The hydrogenation of UAL to UOL is the first step of a consecutive reaction, and a very high conversion at the initial period of reaction would lead to the subsequent hydrogenation of UOL. Thus, many catalysts exhibited a constant or even increased selectivity with the time on stream (TOS). ,,,,,,, However, some researchers have reported that the selectivity to UOL decreased with the TOS over the catalysts of PtZn/CeO 2 , Pt/Ce x Zr 1–x O 2 , Au/CeO 2 , and Pt/CeO 2 -M. ,,, It seems that these catalysts are all supported on the Ce-contained oxide, but the in-depth mechanism remains unclear. Some researchers proposed that the decrease in selectivity might be ascribed to the structure change of the catalyst or the poisoning of the active sites …”

Zirconium phosphate supported-silver nanoparticles for selective hydrogenation of nitrobenzene into azoxybenzene compounds

“…This coordination interaction enabled restraining the Ag particle growth during NaBH 4 reduction. 25 Furthermore, the surface acidity of the 1%Ag/ZrP-R catalyst was further decreased after NaBH 4 treatment, suggesting that NaBH 4 could neutralize the surface phosphate group via an acid–base reaction. Conversely, the absence of moderately and strongly acidic sites on the 1%Ag/ZrO 2 -R catalyst (Fig.…”

“…24 Besides, their surface acidity and basicity were closely associated with functional groups over supports, which contributed to their catalytic activity. [25][26][27] For example, it was reported that the introduction of N elements in molybdenum oxide regulated the electronic structure of Mo, leading to an enhancement of acidity, which favored the adsorption of NB. 28 Additionally, NiCoB catalyst showed an outstanding performance in selective hydrogenation of p-chloronitrobenzene into p-chloroaniline after modification with W or La atoms.…”