Facile Synthesis of Well‐Dispersed Pd Nanoparticles on Ti‐Doped CeO₂ Nanosheets and Their Use as Catalyst in the Hydrogenation of 4‐Nitrophenol

Abstract

We report a facile preparation method of Ti-doped CeO 2 nanosheets and their use as supports for palladium (Pd) deposition. The nanosheets were fabricated by the coordination-precipitation method, and Pd nanoparticles were placed on the surfaces in situ. The obtained Pd-loaded nanosheets Ti x Ce 1-x O 2 -Pd were applied as catalysts in the hydrogenation of 4-nitrophenol (4-NP). While the catalyst supported by pure CeO 2 nanosheets exhibited a 4-NP conversion of 40 % in 10 min, doping a small amount of Ti into the support led to a [a]

Preparation of Highly Uniform Polyurethane Microspheres by Precipitation Polymerization and Pd Immobilization on Their Surface and Their Catalytic Activity in 4-Nitrophenol Reduction and Dye Degradation

“…The reusability of Pd@PUN was explored under the following experimental conditions: 4-NP, 0.067 mM; NaBH 4 , 13.33 mM; Pd@PUN, 1.00 mg/mL; reaction time of 1 min. The results given in Figure suggest that catalytic activity of Pd@PUN obviously deteriorated even in the first four cycles of reuse, with more than 95% of 4-NP reduced within 1 min, a reusability comparable to those previously reported. ,,, However, a more distinct decrease in the catalytic performance was observed at the fifth reuse, where 87.3% of 4-NP was reduced within 1 min, or 3 min was required for a full reduction of 4-NP, although this catalytic performance was still better than some of the reported results. ,,,,,− The catalytic activity of Pd@PUN was sharply decreased thereafter. Only 57.3% of 4-NP was reduced in 1.0 min for the seventh reuse, or as long as 11 min were needed to reach the full reduction of 4-NP.…”

“…It is well understood that the k value is closely linked to the amount of the Pd catalyst used, the larger is the Pd catalyst used, the greater is the k value. In comparison with these reported constant k ’s (Table S2), it was found that the k value obtained in this study (4.96 min –1 with Pd/4-NP = 0.47) was the highest among all the values listed, even for the cases where a much higher amount of the Pd catalyst was used, ,,,,,− indicating a significantly high performance of this Pd@PUN catalyst. PUN is rich in O and N atoms, both the atoms contain lone pair electrons, which can coordinate with transition metals through strong interactions of complexation, facilitating therefore homogeneous Pd distribution on the surface of PUN microspheres and preventing their coalescing and leaching away.…”

“…The results given in Figure 6 suggest that catalytic activity of Pd@PUN obviously deteriorated even in the first four cycles of reuse, with more than 95% of 4-NP reduced within 1 min, a reusability comparable to those previously reported. 41,45,47,48 However, a more distinct decrease in the catalytic performance was observed at the fifth reuse, where 87.3% of 4-NP was reduced within 1 min, or 3 min was required for a full reduction of 4-NP, although this catalytic performance was still better than some of the reported results. 8,32,35,40,41,44−48 The catalytic activity of Pd@PUN was sharply decreased thereafter.…”

“…This meant that 4-NP reduction was catalyzed by Pd@PUN, followed the pseudo-first-order kinetics, with a kinetics constant k of 4.96 min –1 . Many studies have been reported on 4-NP reduction with Pd-supported catalysts using a great variety of supports, including different inorganic composites, magnetic materials, and in particular various polymer supports. ,,,,,− The rate constant k was given in a large number of these studies (Table S2). It is well understood that the k value is closely linked to the amount of the Pd catalyst used, the larger is the Pd catalyst used, the greater is the k value.…”

Solid‐State Synthesis of Silver Nanoparticles and Their Catalytic Application in Methylene Blue Reduction

“…. Noble metal NPs such as silver, gold, platinum or palladium, act as an effective catalyst in nitrophenols and organic dye reduction . A lot of interest has been devoted to noble metal clusters and nanoparticles as a catalyst for redox reactions of 4‐nitrophenol and methylene blue .…”