Spatial Location and Microenvironment Engineering of Pt-CeO₂ Nanoreactors for Selective Hydrogenation of Cinnamaldehyde to Cinnamyl Alcohol

Abstract

More than 25% of chemical transformations involve at least one hydrogenation step. Selective hydrogenation of unsaturated aldehydes is an essential process in the industrial production of pesticides and pharmaceutical synthesis. Since CC hydrogenation with lower bond energy is thermodynamically favored over CO hydrogenation, the selective hydrogenation of cinnamaldehyde (CAL) to cinnamyl alcohol (COL) is relatively challenging. Herein, we report a series of Pt-CeO2 nanoreactors with different spatial locations and microenvironments of Pt nanoparticles (NPs) on hollow CeO2 that are active for the selective hydrogenation of CAL to COL. We show the effects of active metal spatial location, microenvironment, metal–support interactions, and Fe doping on the activity and selectivity within Pt-CeO2 nanoreactors. Pt@Fe-CeO2 shows excellent catalytic performance with an 88.9% selectivity for COL at a CAL conversion of 97.2%. The variations of the electronic and crystal structure after Fe doping, simultaneously, and the linear adsorption of CAL on the CeO2 hollow structure contribute to the high performance of selective hydrogenation to COL. Our findings might shed light on the rational design of the nanoreactors for catalytic organic transformations with desired selectivity.

Enhanced Activity of Alkali-Treated ZSM-5 Zeolite-Supported Pt-Co Catalyst for Selective Hydrogenation of Cinnamaldehyde

“…Moreover, owing to the conjugated C=O and C=C bonds, the selective hydrogenation of C=O bonds to cinnamyl alcohol (COL) was not thermodynamically favorable. Therefore, the highly selective hydrogenation of CAL to COL was still a conundrum [ 8 , 9 , 10 ].…”

Enhanced Selective Hydrogenation of Cinnamaldehyde to Cinnamyl Alcohol over Silica-Coated Pt–CoxOy Hybrid Nanoparticles

“…4,5 Great efforts for this reaction have been devoted to designing metal-based selective catalysts, including employing bimetallic alloys, 6 metal−support interaction, 7−9 and steric hindrance. 10−13 In general, noble metals, including Pt, 11,14 Pd, 7,15 and Au, 16 can efficiently catalyze hydrogenation of CAL, but the poor reserves limit their wide applications.…”

Defect engineering and spilt-over hydrogen in Pt/(WO3–TH2) for selective hydrogenation of CO bonds

“…[17][18][19] Selective hydrogenation of a,b-unsaturated aldehydes (for instance, cinnamaldehyde (CAL)) is not only an important chemical transformation in the field of fine chemicals, but also a useful model reaction to reveal the catalytic mechanism and competition adsorption behavior of CQO and CQC groups over the active sites. [20][21][22][23][24] The lower activation energy of CQC hydrogenation (615 kJ mol À1 ) compared with that of CQO hydrogenation (715 kJ mol À1 ) allows easy hydrogenation of the CQC band of CAL, leading to the lower selectivity towards cinnamyl alcohol (COL). 18,[25][26][27] Over the past two decades, tremendous efforts have been paid to develop efficient catalysts to enhance the hydrogenation selectivity towards COL.…”