A modeling strategy investigation for selective hydrodeoxygenation biomass upgrading of vanillin via metal supported on pyridinic and pyrrolic nitrogen-doped carbon catalysts

To extend the practical application of biomass upgrading conversion to liquid fuel, it is crucial to develop highly catalytic and reversible nonprecious metal catalysts. Herein, we propose a high-throughput density functional theory (DFT) approach to design a high-efficiency catalyst for the selective electrocatalytic upgrading of vanillin via hydrodeoxygenation (HDO). The optimal pyridinic and pyrrolic nitrogen carbon transition metal (TM)-based monolayers exhibit excellent activity for producing 2-methoxy-4-methylphenol (MMP) from vanillin. The pyridinic and pyrrolic nitrogen carbon substrates can provide unique sites to support TM atoms, and TM-pyridinic or pyrrolic N moieties serve as catalytic activity sites for the electrocatalytic upgrading of vanillin. Our DFT calculations suggest that the pyridinic N@TM (TM = Zr, Ru, Rh, Os and Ir) and pyrrolic N@TM (TM = Rh and Os) catalysts possess high activity for MMP synthesized from vanillin, and they have a relatively small limiting potential (U_L) of the rate-determining step. A new route reaction path was used to explore the activity of metal nitrogen-doped carbon catalysts, finding that a single metal atom through strong electron correlation between metal and N₄C₈ sites can improve the activity of the vanillin HDO process. Our results show that pyridinic N@ Ir and pyrrolic N@Rh with limiting potential (U_L) of 0.04 and 0.29 V are the most preferable candidate catalysts for the vanillin HDO process. The high stability and relatively low |U_L| for vanillin electrocatalytic upgrading are the best candidate electrocatalysts. This work proposes new ideas for designing and developing novel catalysts for selective HDO of biomass under real conditions.