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

Abstract

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 H2 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 H2, expressed in terms of the ratio CO2/CO + CO2, was 98–99%, even on total conversion at 423–473 K. The addition of water to the formic acid completely eliminated CO formation and furnished CO-free H2 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. XP spectra of MoO3 in the course of the formation of 1%Mo2C on carbon Norit in the flow of H2 at different temperatures.