Interaction of formic acid with Fe2O3 powders under different atmospheres:an XPS and FTIR study

The interaction between haematite powder and formic acid has been studied a t atmospheric pressure by FTIR and under high-vacuum conditions by X-ray ph otoelectron spectroscopy (XPS) and mass spectroscopy (MS). At room temperat ure formic acid is adsorbed mainly molecularly whereas dissociative chemiso rption is prevalent at higher temperatures. Heating to >500 K causes decomp osition of the formate with the formation of carbon monoxide, carbon dioxid e, hydrogen and water. Suggestions are made concerning the surface acid sit es in connection with the chemisorption and the reaction pathway. The resul ts obtained are compared with those previously achieved by the chemisorptio n of methanol on iron oxide.