A Study on the Effect of pH Value of Impregnation Solution in Nickel Catalyst Preparation for Methane Dry Reforming Reaction

Abstract

The nickel particle size, distribution and interaction with support are crucial to the catalytic performance in dry reforming of methane reaction (DRM). Despite numerous literatures on dry reforming catalysis, the effect of solution pH on the catalytic performance is not well studied. Herein, we designed a series of Ni/SiO 2 catalysts with different Ni particle sizes. The Ni particle size was controlled with altering the pH of the Ni nitrate solution via the addition of HNO 3 or NH 4 OH. X-ray diffraction (XRD) revealed that NH 4 OH promoted Ni/SiO 2 catalysts present smaller NiO nanoparticles, and enhanced metal-support interaction was evidenced from X-ray photoelectron spectra (XPS) and H 2 temperature-programmed reduc-tion (H 2 -TPR) analyses. In addition, according to thermogravimetric analysis and differential scanning calorimetry (TG-DSC) and transmission electron microscopy (TEM) results, the spent catalysts produced less carbon deposition and maintained Ni nanoparticles in smaller size after DRM reaction. Catalysts with nearly uniform and small particle size demonstrated a satisfying resistance to aggregation and carbon deposition, while realizing a high CH 4 , CO 2 and C total conversion (74.5, 83.7 and 79.7%, respectively). The present study provides a simple but effective way to change the metal-support interaction and metal particle size.

A Well‐Defined Core–Shell‐Structured Capsule Catalyst for Direct Conversion of CO2 into Liquefied Petroleum Gas

“…The corresponding adsorption/desorption isotherms and pore size distribution curves are shown in Figure . The SiO 2 support and the Pd/SiO 2 , Pd/SiO 2 ‐S, Pd/SiO 2 –SZ, and Pd/SiO 2 –SZP catalysts exhibited a typical mesoporous structure with a small number of micropores, indicating that the structure of SiO 2 was well preserved during the zeolite hydrothermal preparation process . In contrast to SiO 2 (323.3 m 2 g −1 , 1.12 cm 3 g −1 ), both the surface area and pore volume on Pd/SiO 2 (273.9 m 2 g −1 , 0.92 cm 3 g −1 ) were slightly decreased owing to the introduction of Pd nanoparticles into the SiO 2 pore channel.…”

Formaldehyde Oxidation of Ce0.8Zr0.2O2 Nanocatalysts for Room Temperature: Kinetics and Effect of pH Value

“…On the other hand, ZrO 2 can have special catalytic effects when interacting with specific active components in the system because of its extensive surface oxygen vacancies and significant ion exchange capability [ 11 ]. Several previous papers have investigated the effect of precipitation pH on catalytic efficacy [ 12 , 13 , 14 ]. Clearly, pH is a critical parameter in the design of catalysts.…”