Highly selective hydrogenation of CO2 into formic acid on a nano-Ni catalyst at ambient temperature: Process, mechanisms and catalyst stability

The hydrogenation of CO2 with gaseous hydrogen is currently believed to be the most commercially feasible synthetic method to resolve the serious worldwide greenhouse gas effects. However it is suffering from several disadvantages, such as expensive complex catalysts, and high energy consumption. In this study, a novel method for the hydrogenation of CO2 into formic acid with nano-Ni catalyst is developed. The effects of various parameters on the capability of the catalyst for CO2 conversion were investigated. Furthermore, the HCO3- reduction process on the catalyst was rationalized theoretically with density functional theory simulations. The prepared nano-Ni was demonstrated to be an available catalyst for CO2 conversion into formic acid by employing H-2 as a hydrogen source at ambient temperature and almost constant pressure. Moreover, the nano-Ni catalyst displayed good tolerance with pH variations in CO2 reduction. The formation of formic acid from CO2 reduction on nano-Ni particles was enhanced with an increase NaHCO3 concentration and catalyst dosage. Additionally, theoretical analysis elucidated that the hydrogenation of CO2 into formic acid on nano-Ni catalyst was favorable over attacking the C of HCO3- by the active H and hydroxyl group. (C) 2017 Elsevier Ltd. All rights reserved.