Deciphering the imperative role of ruthenium in enhancing the performance of Ni/Nd₂O₃.Gd₂O₃ in glycerol dry reforming

Abstract

Glycerol dry reforming (GDR) turns glycerol and CO₂ into valuable syngas. The present work aims to decipher the imperative role of Ru metal in enhancing the performance of Ni/Nd₂O₃.Gd₂O₃ in GDR. The unpromoted 15%Ni/Nd₂O₃.Gd₂O₃ and promoted 3%Ru-Ni/Nd₂O₃.Gd₂O₃ catalysts are synthesized via the ultrasonic-assisted impregnation method while XRD, FESEM-EDX, H₂-TPR and CO₂-TPD analyses are used to characterize the catalysts. In this study, the influence of reaction variables such as temperature and the CO₂ to glycerol ratio (CGR) was investigated. In accordance with XRD and FESEM-EDX analyses, the promoted catalyst exhibited a more refined morphology and more uniform Ni dispersion than the unpromoted catalyst. From the reaction study, the promoted 3%Ru-15%Ni/Nd₂O₃.Gd₂O₃ gives higher glycerol conversion (91%), H₂ yield (65%) and CO yield (80%) at a reaction temperature of 800 °C and CGR of 1. This is due to the higher number of available active sites as well as the excellent diffusion of Ni metal across the surface of the catalyst. However, as Ni metal is susceptible to carbon formation and is easily sintered, the production of carbon is unavoidable for the catalysts. The XRD and TPO analyses shown that the addition of Ru reduces the amount of carbon that accumulates on the site of the catalyst, which in turn reduces the rate of deactivation.

Keywords:

• Glycerol dry reforming
• hydrogen
• lanthanide support
• Ni-based catalyst
• Ru promoter
• syngas

Acknowledgement

The authors would like to acknowledge the Ministry of Higher Education, Malaysia for awarding the FRGS research grant vote RDU190197 (FRGS/1/2018/TK02/UMP/02/12) and Universiti Malaysia Pahang (RDU1803118 and PGRS200361) for financial support.