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

Harmless disposal of formaldehyde for hydrogen production is attractive in energy and environmental science. Herein, hydrogen production from formaldehyde steam reforming (FSR) using recyclable NiO/NaF was investigated, and the optimized 4 wt% catalyst exhibited 100% formaldehyde conversion, 104.9% H₂ selectivity and excellent stability at 400 °C. The used catalysts can be easily recycled by water washing and pickling, and the activity of the regenerated catalyst is comparable to that of fresh one. We confirmed that FSR was a rapid surface reaction process, and the special contribution of NaF ensured the high activity of NiO/NaF with low specific surface areas. F ions in the carrier could activate the surface OH–, which promoted adsorption and oxidation to reactants. Furthermore, the in situ DRIFTs study revealed that formate species (HCOO–) was the key intermediate in formaldehyde steam reforming. Formaldehyde was first oxidized to HCOO– and then decomposed into CO₂ and –H.