Renewable hydrogen production by a mild-temperature steam reforming of the model compound acetic acid derived from bio-oil

In this study, steam reforming of acetic acid over Ni/La2O3 catalyst for hydrogen generation was investigated. The experiments were carried out by varying the reaction conditions such as Ni content, reaction temperature, liquid hourly space velocity (LHSV) and steam-to-carbon ratios (S/C), to evaluate the influences of these parameters on the steam reforming reactions for getting the best catalytic performances. The results showed that the Ni/La2O3 catalyst with the Ni loading of 20 wt.% presented the superior activity and selectivity. The reaction temperature, LHSV and S/C strongly influenced the reforming reactions. At T = 623 K, LHSV = 5.1 h−1 and S/C = 7.5:1, the catalyst exhibited the best performances, acetic acid was converted completely, and selectivity to hydrogen exceeded 93%. Moreover, the catalyst presented rather stable performances for the 100 h time-on-stream without any deactivation. Besides, the reaction pathways were also discussed, methyl species was the important intermediate in the reforming reactions, which was the precursors for the formation of the gaseous products, while hydroxyl species was another important intermediate that was important for the formation of hydrogen and elimination of the by-products.

Graphical abstractAt 623 K, Ni/La2O3 catalyst was very active and stable for low-temperature steam reforming acetic acid. Hydrogen selectivity exceeded 90% and CO was presented in trace amount, which was of significance for the use of acetic acid as the promising fuel for proton exchange membrane fuel cells (PEMFC).Figure optionsDownload full-size imageDownload high-quality image (115 K)Download as PowerPoint slideHighlights► Low-temperature steam reforming of acetic acid was investigated over Ni-containing catalysts. ► The reaction parameters have quite different effects on the production of hydrogen. ► Ni/La2O3 had the highest catalytic activity compared to Ni/ZnO, Ni/CeO2 and Ni/ZrO2. ► Methyl species and hydroxyl species played different roles for the formation of the products.