Fabrication of highly dispersed nickel in nanoconfined spaces of as-made SBA-15 for dry reforming of methane with carbon dioxide

The dry reforming of CH₄ (DRM) with CO₂ has received much attention due to the utilization of two green-house gases for the production of syngas. Nickel-containing catalysts have been applied widely in DRM due to their considerable catalytic activity and relative affordable cost, and the activity of catalysts relies on the dispersion of Ni species. Here we developed a nanoconfinement strategy to facilitate the dispersion of NiO in nanoconfined spaces provided by as-made SBA-15 (AS) occluded with the template. The Ni precursor can be inserted into the nanoconfined spaces between silica walls and template in AS by grinding, and in subsequent calcination for NiO formation, aggregation that takes place in conventional calcined SBA-15 (CS) without template can be effectively avoided. Our results show that a high amount of NiO (4 mmol/g, 23 wt%) can be well dispersed in the material from AS (denoted as NiAS), while serious aggregation occurs for the material from CS with the same NiO loading (denoted as NiCS). We also demonstrate that NiAS samples exhibit distinctively higher catalytic activity in DRM with CO₂ compared with their NiCS analogues. For the typical 3NiAS catalyst containing 3 mmol/g NiO, the conversions of CO₂ and CH₄ are 64.2% and 53.7% at 750 °C respectively, which are evidently higher than that of CO₂ (40.7%) and CH₄ (29.0%) over 3NiCS. Furthermore, the NiAS materials present good coking-resistance, while their NiCS counterparts suffer from serious coking.