Photocatalytic reforming of glycerol to H₂ in a thin film Pt‐TiO₂ recirculating photoreactor

BACKGROUND: With an increase in global bioenergy production, the ‘biorefinery concept’ has now become a significant focus of research. The desire to achieve efficient conversion of biomass material into both energy and value-added products requires a combination of technologies and processes. As such, the photocatalytic reforming of feedstocks such as glycerol to hydrogen (H₂) has a lot of potential.

RESULTS: Reported here is the first example of a thin film-based photocatalytic system capable of achieving H₂ evolution using a glycerol feedstock. Using a titania (TiO₂) sol–gel, glass columns were coated with a thin TiO₂ layer before using photodeposition to add platinum (Pt) as a co-catalyst. The coated columns were assembled into a simple yet effective recirculating system which used low power UV irradiation. Under optimum conditions (two coated columns and a 40 mL min⁻¹ flow rate), a steady state of 0.9 μmol min⁻¹ H₂ with a photonic efficiency [η_photon (%)] of 10.22 % was achieved. Furthermore, only one column showed flaking and loss of coating whereas the remaining columns were stable for the duration of the study, which equated to > 100 h of experimental testing including replicates and determining optimal parameters.

CONCLUSION: H₂ evolution via photocatalytic glycerol reforming in a Pt-TiO₂ thin film catalyst recirculating system has been demonstrated under UV irradiation and ambient conditions. The system developed highlights that it is both catalyst development and reactor engineering that are required to continue to advance the field of photocatalysis.