Synergistic Effect of a Ni/Al2O3+YSZ Nanocomposite for the Steam Reforming of Biogas in the Presence of Electric Fields

Abstract

There is an increasing interest in using biogas as a renewable energy source to produce green hydrogen via steam reforming. The high-energy consumption associated with this process has motivated the pursuit of alternative approaches to process raw biogas at lower operating temperatures and without the need for large amounts of steam to prevent catalyst deactivation. The present study discusses the results obtained for the steam reforming of raw biogas in the presence of electric fields, using a nanocomposite catalytic material prepared by physically mixing yttria-stabilized zirconia and a Ni/Al₂O₃ catalyst. The experiments are conducted using a parallel plate capacitor reactor operated at 700 °C and 1 atm. The results indicate that by applying an external electric field (EEF) with a DC voltage of 1.9 kV and a current of 9 mA, a substantial increase in the rates of reaction can be attained. The conversions obtained for CH₄ and CO₂ are higher than the equilibrium values calculated in the absence of an EEF by 23% and 17%, respectively. This shift in the equilibrium is attributed to internal electric fields (IEFs) resulting from the interaction between YSZ and Ni/Al₂O₃, which leads to the creation of an interfacial nanopore structure that could increase the local IEF strength.