Enhanced Hydrogenation Properties of Pd Single Atom Catalysts with Atomically Dispersed Ba Sites as Electronic Promoters

Abstract

Precise adjustment of the electronic structure of heterogeneous catalysts is an effective strategy to improve their catalytic properties. By preparing Pd1Ba1/Al2O3 double atom catalysts with a ball milling method as a model catalyst, we demonstrate an interfacial electronic effect of Pd species induced by Ba single atoms (SAs) as electronic promoters. The introduction of Ba SAs promotes the transfer of electrons from Ba atoms to Pd atoms, forming electron-rich Pdδ+ species. During catalysis, Pd species with the modification of Ba SAs lower apparent activation energy and promote H2 dissociation, which dramatically enhances the catalytic properties in several typical hydrogenation reactions under mild conditions.

Enlarging the Ni–O Bond Polarizability in a Phosphorene-Hosted Metal–Organic Framework for Boosted Water Oxidation Electrocatalysis

“…In contrast to BP NSs, the P 2p orbital in the NiMOF/BP-240 exhibits a −0.2 eV energy shift, also verifying the intimate stacked NiMOF/BP interface with a charge transfer from NiMOF to BP NSs. , The deconvolution of the Ni 2p XPS spectrum of NiMOF/BP-240 (Figure d and Table S2) can be divided into two doublets of Ni 2p 1/2 (874.11 eV, Ni 2+ ; 870.05 eV, Ni δ+ ) and Ni 2p 3/2 (856.41 eV, Ni 2+ ; 852.75 eV, Ni δ+ ) . The Ni 2+ peak in NiMOF/BP-240 demonstrates a +0.6 eV energy shift compared with that in the NiMOF sample, confirming the electron-donating behavior of NiMOF . Such a new Ni δ+ state is found only in the NiMOF/BP heterostructures prepared with Ni-inserted BP NSs as the substrate (Figures S17 and S18).…”

“…50 The Ni 2+ peak in NiMOF/BP-240 demonstrates a +0.6 eV energy shift compared with that in the NiMOF sample, confirming the electron-donating behavior of NiMOF. 51 Such a new Ni δ+ state is found only in the 3d). 54 From the XANES data, the average Ni valence in NiMOF/BP-240 was calculated as +1.61, suggesting the Ni δ+ of the cationic state rather than Ni 0 (supplemental note for Figure S20).…”

Mechanochemistry-Induced Strong Metal–Support Interactions Construction toward Enhanced Hydrogenation

“…From the time- and temperature-dependent catalytic activity results (Figure S20), the enhanced hydrogenation activity of Pd/TiO 2 -SMSI-30 over the Pd/TiO 2 precursor was demonstrated over the tested reaction temperatures in terms of TOF (Figure S21). For example, at 10 and 50 °C, the corresponding activity of Pd/TiO 2 -SMSI-30 was 1.3 and 12.6 s –1 , respectively, whereas that of Pd/TiO 2 was 0.5 and 10.2 s –1 , demonstrating the enhanced catalytic hydrogenation performance being achieved by Pd/TiO 2 -SMSI-30. Figure D displayed the hydrogenation activity in the form of Arrhenius plots with the apparent activation energy values ( E a ), in which E a of Pd/TiO 2 -SMSI-30 (42.9 kJ mol –1 ) was much lower than the Pd/TiO 2 precursor (56.6 kJ mol –1 ), demonstrating the enhanced H 2 activation capability after the NaBH 4 -assisted mechanochemical treatment.…”

Highly Dispersed Ru Nanoclusters Anchored on Hexagonal Boron Nitride for Efficient and Stable Hydrogenation of Aromatic Amines to Alicyclic Amines

“…12,13 For instance, Zhang et al prepared a series of Pd@h-BN composite materials using modified BN as the carrier to achieve a suitable hydrogen overflow and successfully used benzaldehyde in a hydrogenation reaction. 14 Sun et al obtained boron nitride nanosheets by stripping h-BN and prepared a Pd-BNNS catalyst that showed excellent activity and recyclability in the hydrogenation of nitroaromatic. 15 In addition, hexagonal boron nitride contains alkaline sites, which can effectively replace liquid alkali.…”

“…For instance, h-BN has been utilized in the oxidation of alcohols, benzene hydrogenation of nitroaromatic amines, selective hydrogenation of α-β-unsaturated aldehydes, and semihydrogenation of alkynes . Additionally, the two-dimensional structure h-BN has proven to be a fitting support for supported metal catalysts. , For instance, Zhang et al prepared a series of Pd@h-BN composite materials using modified BN as the carrier to achieve a suitable hydrogen overflow and successfully used benzaldehyde in a hydrogenation reaction . Sun et al obtained boron nitride nanosheets by stripping h-BN and prepared a Pd-BNNS catalyst that showed excellent activity and recyclability in the hydrogenation of nitroaromatic .…”