CO 2 Hydrogenation to Methanol via In‐situ Reduced Cu/ZnO Catalyst Prepared by Formic acid Assisted Grinding

Methanol is an essential chemical raw material and potential alternative energy source. In this paper, Cu based catalyst was prepared by the noble solid phase grinding method for CO 2 hydrogenation to methanol. The influence of chelating agent, heating rate, calcination temperature and calcination period of the precursor on catalyst performance were studied in depth. The catalyst precursor with formic acid as a chelating agent was reduced in‐situ when calcined in nitrogen (N 2 ) at 573 K. The formic acid was decomposed, releasing the reducing agents, CO and H 2 , resulting in continuous in‐situ CuO reduction to metallic Cu 0 . XRD, XPS, BET, TG‐DSC, H 2 ‐TPR and other characterization techniques were employed to analyze the catalyst properties. Results revealed that CuO was successfully reduced in‐situ to Cu 0 during calcination process in a nitrogen atmosphere without further reduction. The catalyst prepared by formic acid grinding (F/I−Cu/ZnO) showed highest catalytic activity compared with the conventional catalyst which was further reduced by 5% H 2 (F/H−Cu/ZnO). CO 2 conversion and methanol selectivity reached 33.44% and 84.26%respectively.