Influence of different configurations of Pt supported on Al^V-rich ASA on their catalytic performance in chemoselective hydrogenation evaluated by DFT modeling and experimental validation

The structure of metal nanocatalysts based on single metal atoms (SA), subnanoclusters (NC), and nanoparticles (NP) plays a vital role in governing their catalytic performance. Here, we investigated the effect of different structural configurations of Pt (Pt_SA, Pt_NC, and Pt_NP) supported on penta-coordinated Al (Al^V)-enriched amorphous silica–alumina (ASA) on the selective hydrogenation of aromatic saturated and unsaturated ketones and aldehydes. The predictive information gained by spin-polarized density functional theory (DFT) calculations of the reaction pathways was validated by pertinent catalytic reaction tests. Based on the calculated apparent energy barriers and reaction pathways, a qualitative prediction of the suitability of the different structural configurations of Pt is given for the hydrogenation of specific ketones and aldehydes. For the hydrogenation of aromatic saturated ketones, acetophenone and butyrophenone, the order of the activity is NP > SA > NC. For the saturated aldehydes, benzaldehyde and phenylacetaldehyde, the corresponding order is NP > NC > SA, and for the α,β-unsaturated aldehydes, cinnamaldehyde and benzylideneacetone, it is SA > NC > NP. Pt_NP favors C═O bond over the C═C bond hydrogenation but exhibits low selectivity to the unsaturated alcohol due to consecutive hydrogenation. The validation of the theoretically predicted results by corresponding experimental tests indicates good qualitative agreement between theoretical and experimental results. The combined strategy based on predictive DFT analysis and experimental validation offers an interesting approach for designing and optimizing catalysts.

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