Advantages of Yolk Shell Catalysts for the DRM: A Comparison of Ni/ZnO@SiO2 vs. Ni/CeO2 and Ni/Al2O3

Abstract

Encapsulation of metal nanoparticles is a leading technique used to inhibit the main deactivation mechanisms in dry reforming of methane reaction (DRM): Carbon formation and Sintering. Ni catalysts (15%) supported on alumina (Al2O3) and ceria (CeO2) have shown they are no exception to this analysis. The alumina supported catalysts experienced graphitic carbonaceous deposits, whilst the ceria showed considerable sintering over 15 h of DRM reaction. The effect of encapsulation compared to that of the performance of uncoated catalysts for DRM reaction has been examined at different temperatures, before conducting longer stability tests. The encapsulation of Ni/ZnO cores in silica (SiO2) leads to advantageous conversion of both CO2 and CH4 at high temperatures compared to its uncoated alternatives. This work showcases the significance of the encapsulation process and its overall effects on the catalytic performance in chemical CO2 recycling via DRM.

In Situ X-ray Microscopy Reveals Particle Dynamics in a NiCo Dry Methane Reforming Catalyst under Operating Conditions

“…In recent years, various studies focused on the development of late 3d transition metal-based systems as an alternative to costly noble metals for DMR catalysis. − , Within this context, nickel (Ni)-based catalysts are promising candidates due to their relatively high activity and earth abundance. Nevertheless, the major drawback of monometallic Ni-based catalysts when compared to noble metal-based catalysts is their lower activity and higher susceptibility to deactivation due to coke formation via either methane cracking or the reverse Boudouard reaction. − In order to increase catalyst activity and stability, researchers have implemented various approaches including (i) depositing the catalytic active phase on different support materials, , (ii) reducing the catalyst, particle size, , (iii) developing bimetallic catalysts based on transition metals, − and (iv) transition metal-based core–shell nanoarchitectures. − It has been shown that core-shell systems have the ability to prevent metal sintering and decrease carbon formation, while the production of bimetallic catalysts has been very successful in increasing the catalyst activity, stability, and selectivity. Among 3d transition metals, the addition of cobalt (Co) to Ni-based DMR catalysts results in the highest increase in activity.…”

Precise Modulation of Triple‐Phase Boundaries towards a Highly Functional Exsolved Catalyst for Dry Reforming of Methane under a Dilution‐Free System

“…Remarkably, the conversions last for more than 1000 hours without deactivation, an unprecedented world record. Some recent studies have been conducted to approach high conversion rates without dilution gases, but they have only been able to operate for a short period of time (< 100 hours) and some suffer from severe deactivations [40][41][42][43][44] (Figure 3g). After the long-term stability test, the presence of carbon coking and particle agglomeration is analyzed with TGA-DSC and EDS.…”

Engineering heterogenous catalysts for chemical CO2 utilization: Lessons from thermal catalysis and advantages of yolk@shell structured nanoreactors

“…However, the literature concentrates largely on the use of Ni and SiO 2 with minimal variation from this combination. Several works concerning the use of Ni@SiO 2 YS materials for the DRM reaction have been reported in recent years [276,311,[315][316][317], demonstrating a high level of effectiveness for this material combination. Notably, Lu et al [311] detail a simple synthesis for a multicore YS material that displayed no sign of deactivation over 50 hours of continuous exposure to the DRM reaction, though their technique produced a wide distribution of particle sizes.…”

“…12(b), traditional catalysts collapsed after a few hours of reaction while the encapsulated materials remain stable. Our seminal works [316,317] serve as a proof of concept to showcase the efficiency of Ni@SiO 2 catalysts for gas-phase CO 2 recycling via DRM. Nevertheless, we observed the formation of well-defined carbon nanotubes (Fig.…”