The complementary relationship between Ru/Al2O3 and Ni/Al2O3 catalyst for dry reforming of methane

Abstract

We report a physical mixture of 1 wt% Ru/Al2O3 with 10 wt% Ni/Al2O3 obtained from the NiAl2O4 phase as a highly active, durable, and cost-effective catalyst for the dry reforming of methane (DRM). Since the presence of Ru facilitates the reduction of Ni oxides, resulting in not only enhanced CH4 conversion but also increased carbon deposits, the optimal formation of metallic Ni sites is a key factor for the mixed Ru-Ni catalyst. Here, we used a NiAl2O4/Al2O3 catalyst and reduced it with CH4 under reaction conditions for the limited formation of metallic Ni sites, depending on the reaction temperatures. As a result, this mixed catalyst showed higher performance for DRM than a Ru single catalyst with mild carbon deposits at both low (650 ℃) and high (800 ℃) temperatures taking advantage of improved cost-effectiveness, on top of that, the existence of a Ni catalyst compensated for the loss of activity of a Ru catalyst due to sintering. We also suggest different mechanisms for DRM over the Ru catalyst and Ni catalyst respectively from the results of temperature-programmed surface reaction and CH4/CO2 cycling experiments.