Keele Research Repository

The utilisation of biogas as an energy source or as a feed stock for the chemical industry would help to lower the present wasteful and environmentally unfriendly venting of greenhouse gases to the atmosphere. One obstacle to this becoming a reality include finding a catalyst that is active towards carbon dioxide reforming of methane as well as resistance to carbon deposition and sulphur poisoning.

As a potential alternative to supported nickel catalysts, a nickel doped perovskite has been produced via a hydrothermal synthesis method for reforming biogas. The selected perovskite, SrZrO3, was doped with 4 mol % nickel into the structure and shown to be phase pure by XRD. This material was rigorously tested catalytically using a range of biogas conditions.

4 mol% Ni doped SrZrO3 was shown to be resistant to carbon deposition under high temperature, methane rich biogas reforming conditions with no observable trend between the amount of carbon formed and the time on stream. This catalyst showed high activity and selective towards the formation of the desired products, an equimolar mixture of hydrogen and carbon monoxide.

As naturally derived biogas is not a pure mixture of methane and carbon dioxide, studies into the effect that two of the other important components of biogas, water and sulphur containing compounds, were carried out. The perovskite material was seen to be stable towards continued dry reforming of methane irrespective of the inclusion of water, and at elevated reaction temperatures was able to convert the water into the required products of hydrogen and carbon monoxide.

The effect of hydrogen sulphide was studied and the perovskite material was seen to be susceptible to sulphur poisoning. However the extent and the recovery from this type of deactivation was an improvement on that seen by Ni/YSZ and 5% ceria doped Ni/YSZ