Catalytic production of anilines by nitro-compounds hydrogenation over highly recyclable platinum nanoparticles supported on halloysite nanotubes

Valorization of Waste Tires via Catalytic Fast Pyrolysis Using Palladium Supported on Natural Halloysite

“…Halloysite nanotube (HNT) was prepared using our previously reported method. 25 The preactivated HNT (0.1 g) was dispersed in 50 mL of distilled water and sonicated for 10 min. Then, appropriate volumes of Na 2 PdCl 4 (9.6 mmol L −1 ) and NaOH (1.0 mmol L −1 ) solutions were added and stirred for 4 h. Subsequently, 10 mL of freshly prepared aqueous NaBH 4 (50 mmol L −1 ) solution was added, and the mixture was stirred for another 1 h to completely reduce the metal precursor.…”

“…The negatively charged [PdCl 4 ] 2− ions can be strongly anchored onto the inner surface by ligand exchange with Al−OH/Al−O − providing the preferential deposition of the Pd NPs inside of the halloysite after the reduction process. 25 In PdHout, the Pd NPs were mainly distributed on the outer surface of the support with a particle size of 1.6 ± 0.1 nm (Figure 2b). According to the ATR-FTIR characterization, we suggest that the selective external chemical modification of the support provide the formation [PdCl 4−x (NH 2 −H-APTMS) x ] x−2 species, which assisted the Pd NP deposition as well as their homogeneous distribution on the external surface of the carrier.…”

“…21 preferentially immobilized on the outer surface of the tube, in line with our previously reported results. 25 Metal loading in the Pd-based catalysts was confirmed by ICP-MS, and the results are shown in Table 2. The similarity of experimental and nominal metal contents indicates that all the metal precursor was deposited on the support during synthesis and confirms the metal loading of the as-prepared catalysts.…”

“…26 This trend is in line with our previous reported results for the APTMSassisted deposition of noble metals in nanotubular supports. 25 The main advantage of this synthetic strategy is the control of the metal NP size distribution by the chemical interaction between the metal precursor and −NH 2 surface functional groups.…”

Enhanced Magnetorheological Behavior of a Carbonyl‐Iron‐Based Fluid via Addition of Fe3O4/Halloysite‐Nanotube Composite Particles

“…They can be conveniently suspended in solutions or polymeric base liquids and have been used in various fields for preparing catalysts, carriers, and adsorbents. [24][25][26] The addition of HNTs to MRFs improves their stability, but weakens their MR properties. [27] Magnetic composites with HNTs have not yet been reported as additives for MRFs.…”