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.

Graphical Abstract

XP spectra of MoO3 in the course of the formation of 1%Mo2C on carbon Norit in the flow of H2 at different temperatures.