Hydrogen production from formaldehyde steam reforming using recyclable NiO/NaCl catalyst

The harmless treatment of formaldehyde and co-produce of hydrogen has drawn a lot of interest in the field of both energy and environmental science. Herein, NiO supported on NaCl (NiO/NaCl) was designed as catalyst to produce hydrogen via formaldehyde steam reforming (FSR). At 450 °C, the optimal 3 wt% NiO/NaCl catalyst had 102.8% H₂ selectivity, close to 100% formaldehyde conversion and 48-hour stability. The used catalysts can be easily regenerated and recycled by washing with water and acid. The regenerated 3% NiO/NaCl catalyst had comparable catalytic performance as the fresh one. Since the specific surface area of the NiO/NaCl catalysts was as low as 1.3 m²·g⁻¹, the FSR reaction should be a fast surface reaction process. The reaction was further investigated by in situ DRIFTs, H₂-TPR and XPS. The excellent catalytic activity can be attributed to the interaction between the NiO active component and NaCl support, which can activate the surface hydroxyl groups and promote the adsorption and oxidation of the reactants.