Effective production of formic and acetic acid via CO2 hydrogenation with hydrazine by using ZrO2 catalysts

Abstract

Amorphous ZrO2 and Mn addition to ZrO2 catalysts were studied for CO2 hydrogenation to formic acid and acetic acid via an indirect hydrogen source, i.e., hydrazine monohydrate. The amorphous ZrO2 was synthesized by the precipitation method and the Mn addition was carried out by two different methods, namely, the physical mixing method (Mn+ZrO2) and the co-precipitation method (Mn-ZrO2). The XRD and XPS results show that the enhanced metal-support interaction in the co-precipitation method leads to the stabilization of Mn in its higher oxidation state. The physical mixing method leads to the stabilization of Mn in its lower oxidation state and/or metallic form, which improves hydrogen production from hydrazine and thus CO2 hydrogenation. Optimization of reaction parameters was investigated with changes in reaction conditions such as reaction time, CO2 pressure and catalyst weight.