Predicting the optimal chemical composition of functionalized carbon catalysts towards oxidative dehydrogenation of ethanol to acetaldehyde

A significant challenge in developing ideal carbon-based catalysts for oxidative dehydrogenation of ethanol to acetaldehyde is to correlate the catalytic efficiencies with the multiple functional sites on the catalysts qualitatively and quantitatively. By making a series of two-dimensional carbon catalysts with varied oxygen and nitrogen functional sites and testing the catalytic performances, we show the roles the specific functional groups played in the catalytic conversion process. Moreover, a map that includes the quantitative ratio of different active sites and the acetaldehyde yield is provided, which can be used to predict the ideal structure of a potential catalyst. The resulted catalyst showed the ethanol conversion rate of 54 %, the acetaldehyde selectivity of 84 %, and the attractive yield of acetaldehyde up to 45 %, surpassing the performances of the majority of reported carbon-catalysts tested under a similar condition. Our prediction reveals that the ideal balance of surface pyridinic-N/ graphitic-N in a carbon catalyst should be in the range of ~0.7–1.0 while the C-O/ CO is ~0.7–0.8, which could be very useful to the researches in this field. The combination of experiments, theoretical simulations, and especially the quantitative prediction deepens the understanding of the catalysts and the catalytic reactions, which is expected to be extended to the study of other catalytic processes. A method is established to predict the subtle balance of nitrogen and oxygen functional sites in a carbon catalyst, which results in the high selectivity of direct oxidative dehydrogenation of ethanol to acetaldehyde. [Display omitted] •A 2D O-N-containing polymer nanosheet material (ONPNs) was synthesized via a controllable chemical crosslinking reaction.•Acetaldehyde selectivity was significantly enhanced by optimizing the chemical component of a carbon catalyst.•The N species promote the dissociation and adsorption, while the O species facilitate the dehydrogenation process.•The specific functional groups correlated with catalytic activities to form a map which could predict the ideal structure.