Resource utilization of waste V2O5-based deNOx catalysts for hydrogen production from formaldehyde and water via steam reforming

The harmless disposal of abandoned and toxic V2O5(WO3)/TiO2 (VWT) deNOx catalysts has become a worldwide great demand, a new resource path for hydrogen production from steam reforming of formaldehyde and water using the waste VWT deNOx catalysts as catalyst carriers was proposed. The waste V2O5-based catalysts supported NiO (N/VWT) catalysts prepared by impregnation method were comparatively studied for hydrogen production. The H2 and CO selectivity of the optimum N/VWT separately reached 100% and 72.5%, and the formaldehyde conversion of the N/VWT reached 86.3% at 400 ℃ and higher than 93.0% at 450–600 ℃. Analysis showed that the hydroxyl species played the most important role, and its richness determined the catalytic performance directly. The high acid sites and excellent redox properties were beneficial to enhance the catalytic performance. The in situ DRIFT study verified that the hydrogen bonds between formate species and hydroxyl groups reduced reaction steps, which accelerated the progress of the reaction. The adsorbed formaldehyde transformed to formate species firstly, and then produced H2 and CO2 (or CO) by dehydrogenation. Ultimately, the resource utilization path not only completely solved the harmless problems of the waste V2O5-based deNOx catalysts and formaldehyde, but also contributed to the hydrogen production.