Impact of preparation method on nickel speciation and methane dry reforming performance of Ni/SiO2 catalysts

Abstract

The methane dry reforming reaction can simultaneously convert two greenhouse gases (CH4 and CO2), which has significantly environmental and economic benefits. Nickel-based catalysts have been widely used in methane dry reforming in past decade due to their low cost and high activity. However, the sintering and coke deposition of catalysts severely limit their industrial applications. In this paper, three Ni/SiO2 catalysts prepared by different methods were systematically studied, and the samples obtained by the ammonia evaporation method exhibited excellent catalytic performance. The characterization results such as H2-TPR, XPS and TEM confirmed that the excellent performance was mainly attributed to the catalyst with smaller Ni particles, stronger metal-support interactions, and abundant Ni-O-Si units on the catalyst surface. The anti-sintering/-coking properties of the catalyst were significantly improved. However, the Ni/SiO2-IM catalyst prepared by impregnation method had uneven distribution of nickel species and large particles, and weak metal-support interactions, showing poor catalytic performance in methane dry reforming. Since the nickel species were encapsulated by the SiO4 tetrahedral network, the Ni/SiO2-SG catalyst prepared by sol-gel method could not expose more effective active sites even if the nickel species were uniformly dispersed, resulting in poor dry reforming performance. This study provides guidance for the preparation of novel anti-sintering/-coking nickel-based catalysts.

Recent Advances in Ni-Based Catalysts for CH4-CO2 Reforming (2013–2023)

“…The catalyst exhibited better low-temperature reforming performance compared to the conventional impregnation method. Chen et al [82] prepared three Ni/SiO 2 catalysts using impregnation, sol-gel, and ammonia evaporation methods, respectively, to investigate the relationship between catalyst preparation methods and catalytic performance. The catalyst obtained by the ammonia evaporation method demonstrated good catalytic performance.…”

Metal–support interactions for heterogeneous catalysis: mechanisms, characterization techniques and applications

“…Furthermore, Ni/SiO 2 catalysts prepared by various methods were tested by Chen et al , and the samples attained by ammonia evaporation had outstanding catalytic property. 53 Based on the characterization results, in addition to SMSIs, the catalyst had undersized Ni particles and an abundance of Ni–O–Si units, which contributed to its excellent performance. Significant improvements were observed in the anti-sintering/coking properties of the catalysts.…”

Confinement effects over Ni-based catalysts for methane dry reforming

“…So far, many research strategies have been developed to address the issue of carbon deposition and agglomeration in nickel-based catalysts, such as optimization of catalyst preparation methods, 34,63 doping with additives, 54,64–66 creating core–shell structure, etc. 67–70 However, there are few reviews on the confinement effects in Ni-based catalysts for MDR.…”

“…Nevertheless, Ni-based catalysts face prominent problems of sintering and coking in MDR reactions. [32][33][34][35][36][37][38] Therefore, how to develop and design Ni-based catalysts with anti-sintering and anti-coking properties has become one of the hot topics in this field.…”

“…45,[60][61][62] In addition, enhanced interaction between the nickel species and the catalyst support can also improve Ni-based catalysts' anti-sintering. 27,33 So far, many research strategies have been developed to address the issue of carbon deposition and agglomeration in nickel-based catalysts, such as optimization of catalyst preparation methods, 34,63 doping with additives, 54,[64][65][66] creating core-shell structure, etc. [67][68][69][70] However, there are few reviews on the confinement effects in Ni-based catalysts for MDR.…”