Long-term stable catalyst for dry reforming of Methane: Ni-Nanocluster embedded in silica

Abstract

Dry reforming of methane (DRM) is a fascinating catalysis to convert greenhouse gases into valuable syngas; however, the catalyst deactivation due to coking and sintering has posed a significant obstacle to practical use. Here, we introduce a novel synthetic approach for creating Ni nanoclusters (similar to 2 nm) embedded inside silica (NiES), without using any catalytic metal promoters. Compared to conventional Ni-SiO2 catalysts, the NiES catalyst could fully utilize unique Ni-O-Si bonding within a bimodal silica matrix. This leads to exceptional reactivity and long-term stability for DRM without noticeable deactivation over 500 h of operations. Notably, characterizations revealed that Ni nanoclusters maintained their particle size even after this extended operation, significantly contributing to their resistance against carbon coking. These Ni clusters appeared to efficiently promote CH4 decomposition, while the continuously regenerated OH groups from dissociative adsorption of CO2 assisted in oxidizing carbon species. This study will substantially contribute to the swift implementation of the catalytic DRM process.