Emma Lovell

Ni-SiO2 Catalysts for the Carbon Dioxide Reforming of Methane: Varying Support Properties by Flame Spray Pyrolysis

Silica particles were prepared by flame spray pyrolysis (FSP) as a support for nickel catalysts. The impact of precursor feed rate (3, 5 and 7 mL/min) during FSP on the silica characteristics and the ensuing effect on catalytic performance for the carbon dioxide, or dry, reforming of methane (DRM) was probed. Increasing the precursor feed rate: (i) progressively lowered the silica surface area from ≈340 m2/g to ≈240 m2/g; (ii) altered the silanol groups on the silica surface; and (iii) introduced residual carbon-based surface species to the sample at the highest feed rate. The variations in silica properties altered the (5 wt %) nickel deposit characteristics which in turn impacted on the DRM reaction. As the silica surface area increased, the nickel dispersion increased which improved catalyst performance. The residual carbon-based species also appeared to improve nickel dispersion, and in turn catalyst activity, although not to the same extent as the change in silica surface area. The findings illustrate both the importance of silica support characteristics on the catalytic performance of nickel for the DRM reaction and the capacity for using FSP to control these characteristics.

A sea-change: manganese doped nickel/nickel oxide electrocatalysts for hydrogen generation from seawater

The practical implementation of electrolytic water splitting systems (especially those powered by renewable energy resources, such as solar and wind) requires active and stable catalysts for the hydrogen evolution reaction (HER). The development of catalysts that can compete with, or exceed, the performance of the exorbitant platinum (Pt)-based benchmark is highly desirable. Here, we demonstrate the development of a highly active HER catalyst electrode, exhibiting Pt-like performances in both neutral electrolytes and natural seawater. The catalyst was obtained by pyrolysing a manganese-based metal organic framework (Mn-MOF) on nickel foam (Ni-F). We discovered for the first time that nickel foam not only acts as the substrate for catalyst growth but also provides nickel species that interact with the Mn-MOF, resulting in the formation of Mn doped nickel oxide/nickel hetero-structures on Ni-F (Mn–NiO–Ni/Ni-F). The potential utilization of this catalyst electrode for commercial applications was demonstrated in a self-customized water electrolyzer pack powered by photovoltaic cells.