High catalytic efficiency of Pd nanoparticles immobilized on TiO₂ nanorods‐coated ceramic membranes

Abstract

In this work, we designed and constructed an efficient and reusable membrane catalyst by loading palladium (Pd) nanoparticles on TiO2 nanorods (NRs)‐coated ceramic membrane. The morphology and structure analysis show that the TiO2 NRs with a width of 200 nm–1000 nm and a length of about 4000 nm can be successfully synthesized on the ceramic membrane by a two‐step hydrothermal method. The Pd nanoparticles with an average particle size of 4 nm can be uniformly distributed on the TiO2 NRs‐coated ceramic membrane. The catalytic performance evaluation highlights that higher catalytic activity and stability are observed for the Pd nanoparticles immobilized on the TiO2 NRs‐coated ceramic membrane compared to the ones loaded on the unmodified ceramic membrane in the liquid‐phase p‐nitrophenol hydrogenation. The TiO2 NRs can provide more areas for the deposition of Pd nanoparticles, and then more Pd nanoparticles with better dispersion can be loaded on the membrane, leading to superior catalytic activity. The interaction between Pd nanoparticles and TiO2 provides less leaching of Pd nanoparticles and higher catalytic stability.

Continuous and complete conversion of high concentration p‐nitrophenol in a flow‐through membrane reactor

“…TiO 2 nanorod arrays on sheet Al 2 O 3 ceramic membranes (circular, 3.2 cm in diameter, 1.6 mm in thickness and 30% in porosity) were obtained via the following two-step hydrothermal method. 26 Twenty mL of concentrated hydrochloric acid (Analytical Reagent, This article is protected by copyright. All rights reserved.…”

“…Greater than 90% of the PNP was reduced within 4 hours using a single reaction step, and deactivation was observed after consecutive catalytic cycles. Our group 26 successfully demonstrated that the use of TiO 2 nanorod-functionalized ceramic membranes is an effective approach for enhancing the loading amount of Pd and the corresponding catalytic activity. However, the catalytic membranes obtained when used directly in a batch reactor could not achieve continuous conversion of PNP.…”

One pot synthesis of nano Ag in calcium alginate beads and its catalytic application in p‐Nitrophenol reduction with kinetic parameter estimation and model fitting

“…To achieve this, noble metal nanoparticles can be used as highly efficient catalysts, and these nanoparticles were studied by several research groups. [ 23–26 ]…”

“…To achieve this, noble metal nanoparticles can be used as highly efficient catalysts, and these nanoparticles were studied by several research groups. [23][24][25][26] The current work describes the one-pot green synthesis of silver nanoparticles supported on calcium alginate (CA-Agnp) beads, the characterization of CA-Agnp, and the application as a catalyst for the reduction of p-nitrophenol (p-NP) to p-aminophenol (p-AP) using sodium borohydride as a reducing agent. There are two important ways of preparing CA-Agnp beads, as reported in the literature: (a) the absorption of Ag + ion in the previously prepared beads followed by reduction to silver nanoparticles (Agnp) by some external processes and (b) the preparation of colloidal solution of sodium alginate and Agnp followed by conversion into beads.…”

“…[6,7] Aromatic nitroarenes widely exist in industrial and agricultural wastewater as toxic organic compounds. [23,24] Among different aromatic nitroarenes, p-nitrophenol is the organic toxin that is most commonly found in the environment. To control pollution, the reduction of p-nitrophenol to a useful product (reduction product p-aminophenol is an important intermediate for the synthesis of pharmaceutical drugs) is an efficient method.…”