Syngas Production via CO2 Reforming of Methane over SrNiO3 and CeNiO3 Perovskites

Naushad Ahmad,Salim Manoharadas,Manawwer Alam,Basel Alrayes,Fahad Alharthi,Rizwan Wahab

doi:10.3390/en14102928

Abstract

The development of a transition-metal-based catalyst with concomitant high activity and stability due to its distinguishing characteristics, yielding an abundance of active sites, is considered to be the bottleneck for the dry reforming of methane (DRM). This work presents the catalytic activity and durability of SrNiO3 and CeNiO3 perovskites for syngas production via DRM. CeNiO3 exhibits a higher specific surface area, pore volume, number of reducible species, and nickel dispersion when compared to SrNiO3. The catalytic activity results demonstrate higher CH4 (54.3%) and CO2 (64.8%) conversions for CeNiO3, compared to 22% (CH4 conversion) and 34.7% (CO2 conversion) for SrNiO3. The decrease in catalytic activity after replacing cerium with strontium is attributed to a decrease in specific surface area and pore volume, and nickel active sites covered with strontium carbonate. The stability results reveal the deactivation of both the catalysts (SrNiO3 and CeNiO3) but SrNiO3 showed more deactivation than CeNiO3, as demonstrated by deactivation factors. The catalyst deactivation is mainly attributed to carbon deposition and these findings are verified by characterizing the spent catalysts.

Highlights

Dry, or carbon dioxide reforming of methane (DRM) has gained attention in recent decades, mainly due to the fact that DRM consumes prevalent greenhouse gases i.e., methane and carbon dioxide to produce synthetic gas, which serves as an important raw material for liquid hydrocarbon formation [1,2,3,4,5,6,7,8]
The Temperature-Programmed Reduction (TPR) profiles (Figure 4) aimed to find out the reduction behavior of the perovskites and it was evident that the reduction in oxides of nickel was easier for CeNiO3, while it became difficult in the case of SrNiO3 which is in agreement with the TG-DTG results (Figure 1)
The XRD patterns show that clear peaks of oxides and carbonates of strontium are found for SrNiO3 perovskite, which supports the hypothesis that nickel active sites are covered

Summary

Introduction

Carbon dioxide reforming of methane (DRM) has gained attention in recent decades, mainly due to the fact that DRM consumes prevalent greenhouse gases i.e., methane and carbon dioxide to produce synthetic gas, which serves as an important raw material for liquid hydrocarbon formation [1,2,3,4,5,6,7,8]. The catalytic activity and stability are mainly dependent on the choice of a suitable catalyst [14]. The bottlenecks associated with Ni-based catalysts include the loss of active metal surface area due to sintering and carbon formation during. Many researchers have reported that ceria and its modified supported catalysts provide a promising platform for endothermic DRM processes due to their basicity, to promote CO2 adsorption, and their high oxygen storage capacity/oxygen vacancy for CO2 activation or the gasification of different kinds of carbon precursors [20,21,22,23]. Perovskites have shown excellent performance in catalytic and photovoltaic industries and Ni-based perovskites are favored for DRM as perovskites offer high metal dispersion and thermal stability [24,25]. Several factors contribute to the catalytic performance of a perovskite [28], (a) the choice of element(s) for B-site cation,

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