Facile synthesis of Au embedded CuOx-CeO2 core/shell nanospheres as highly reactive and sinter-resistant catalysts for catalytic hydrogenation of p-nitrophenol

Abstract

Exploring cost-effective catalysts with high catalytic performance and long-term stability has always been a general concern for environment protection and energy conversion. Here, Au nanoparticles (NPs) embedded CuO x-CeO 2 core/shell nanospheres (Au@CuO x-CeO 2 CSNs) have been successfully prepared through a versatile one-pot method at ambient conditions. The spontaneous auto-redox reaction between HAuCl 4 and Ce(OH) 3 in aqueous solution triggered the self-assembly growth of micro-/ nanostructural Au@CuO x-CeO 2 CSNs. Meanwhile, the CuO x clusters in Au@CuO x-CeO 2 CSNs are capable of improving the anti-sintering ability of Au NPs and providing synergistic catalysis benefits. As a result, the confined Au NPs exhibited extraordinary thermal stability even at a harsh thermal condition up to 700 C. In addition, before and after the severe calcination process, Au@CuO x-CeO 2 CSNs can exhibit enhanced catalytic activity and excellent recyclability towards the hydrogenation of p-nitrophenol compared to previously reported nanocatalysts. The synergistic catalysis path between Au/CuO x /CeO 2 triphasic interfaces was revealed by density functional theory (DFT) calculations. The CuO x clusters around the embedded Au NPs can provide moderate adsorption strength of p-nitrophenol, while the adjacent CeO 2-supported Au NPs can facilitate the hydrogen dissociation to form H* species, which contributes to achieve the efficient reduction of p-nitrophenol. This study opens up new possibilities for developing high-efficient and sintering-resistant micro-/nanostructural nanocatalysts by exploiting multiphasic systems.

Green synthesis of crystalline bismuth nanoparticles using lemon juice

“…4a). 8,27,29 The reaction rate almost follows pseudo-rst-order kinetics agreeing with the Langmuir-Hinshelwood mechanism; in which two reactants react aer adsorption on the solid surface, and then the product desorbs. The rate constant (k) was determined from the plot of ln(A/A 0 ) vs. time (Fig.…”

“…4b) according to the previous reports. 7,8,28,29 The k value of 0.0134 min À1 (activity factor ¼ 0.1 s À1 g À1 ) is lower than previously reported PVP-coated bismuth nanodots (6.033 s À1 g À1 ) 8 and starch coated BiNPs (0.02751 s À1 ). 7 The lower catalytic rate of our BiNPs can be attributed to the electrostatic repulsion of 4-nitrophenolate ions with negatively charged BiNPs (zeta potential value ¼ À31.7 mV) in the reaction mixture.…”

Insight into the Morphology‐Dependent Catalytic Performance of CuO/CeO2 Produced by Tannic Acid for Efficient Hydrogenation of 4‐Nitrophenol

“…We have employed the Vienna Ab initio Simulation Package (VASP) [44] to carry out all DFT calculations within the generalized gradient approximation (GGA) using the Perdew‐Burke‐Ernzerhof (PBE) [45] functional. The GGA+U correction (U−J) was applied for Ce and Cu to be 4.5 and 4.0, respectively [46] . The projected augmented wave (PAW) potentials [47] were utilized to present the ionic cores and take valence electrons into account using a plane‐wave basis set with a kinetic energy cutoff of 400 eV.…”

The Synergistic Effect of Oxygen Vacancy and Carbon Interface Engineering in Hollow Cerium Oxide to Achieve Enhanced Oxygen Reduction Performance

“…As one of the most significant rare earth oxides with abundant reserves, cerium oxide (CeO 2 ) has attracted increasing attention owing to its high oxygen storage ability, reversible conversion from Ce 4+ to Ce 3+ , and inherently decent conductivity. , The (111) facet of CeO 2 is the most stable low index surface. , Ce 3+ appears in large quantities that can generate oxygen vacancies and also can adsorb oxygen. Therefore, it is easy to produce superoxide O 2 – on the surface of CeO 2 (111). − At present, a few CeO 2 -based electrocatalysts have been reported for oxygen reduction, but the catalytic efficiency seems to be insufficient and the catalytic mechanism is still unclear . In recent years, the design and synthesis of hollow nanostructures have become important research fields in chemistry and materials science.…”