Efficient hydrogen production from high-concentration aqueous formic acid over bio-based γ-Mo2N catalysts

Formic acid is regarded to be one of the most prospective hydrogen carriers. Effective screening of the fitting non-noble-metal-based heterogeneous catalysts to substitute the expensive noble-metal-based ones for FA dehydrogenation is considered as a key to the commercial application for hydrogen economics. Herein, dehydrogenation of liquid neat FA achieved a gas production value of 1753.5 mL/g_cat./h at 94 °C by using a biomass-derived γ-Mo₂N based catalyst synthesized from the earth-abundant molybdenum and soybean with a facile pyrolysis process. The effect of material ratio, pyrolysis temperature on the catalytic performance of FA dehydrogenation were studied in details. In particular, the catalyst obtained at a pyrolysis temperature of 700 °C, weight ratios of ammonium molybdate to soybean of 0.2/1 exhibited the highest activity. In addition, the catalytic activity increased with the increase of FA concentration, but conversely, the dehydrogenation selectivity decreased with the increasing FA concentration. Moreover, it was found that the Bio-Mo₂N catalyst was rather stable over the 40 h continuous reaction period.