Production of CO-Free H2 by Formic Acid Decomposition over Mo2C/Carbon Catalysts

The vapor phase decomposition of formic acid was studied over supported Mo2C catalysts in a flow system. Mo2C deposited on silica is an effective catalyst for both the dehydrogenation of formic acid to yield H-2 and CO2, and its dehydration to yield H2O and CO. The extent of the decomposition approached 100% at 623 K. Preparation of the Mo2C catalyst by the reaction of MoO3 with a multiwall carbon nanotube and carbon Norit, however, dramatically altered the product distribution. Dehydrogenation became the dominant process. In optimum case, the selectivity for H-2, expressed in terms of the ratio CO2/CO + CO2, was 98-99%, even on total conversion at 423473 K. The addition of water to the formic acid completely eliminated CO formation and furnished CO-free H-2 on Mo2C/carbon catalysts at 373-473 K. Another feature of the Mo2C catalyst is its high stability. No changes in activity or selectivity were observed within 10 h.