Embedding Single Platinum Atoms Into Nickel Nanoparticles Affords Highly Selective Catalysts for Lignin Conversion

Lignin is an abundant biomass source that can be converted into value-added aromatic platform chemicals. Due to the highly complex polyphenolic-structure of lignin, depolymerisation without a prior chemical treatment is challenging, and new, superior catalysts are required. Atomically dispersed catalysts containing isolated atoms are able to maximize the atomic efficiency of noble metals in a catalytic process, simultaneously providing an alternative strategy to tune the activity and selectivity by alloying with other abundant metal supports. Herein, we report a highly active and selective catalyst comprising monodispersed (single) Pt atoms on Ni nanoparticles supported on carbon (denoted as Pt1Ni/C where Pt1 represent single Pt atoms), designed for the reductive depolymerization of lignin. Selectivity towards 4-n-propylsyringol and 4-n-propylguaiacol, in which the aromatic rings are preserved, exceeds 90%. The activity and selectivity of the engineered Pt1Ni/C catalyst in the reductive depolymerization of lignin may be attributed to synergistic effects between the Ni nanoparticles that promote dissociation of H2 and supply the absorbed hydrogen to the single Pt atoms where cleavage of the C-O bonds takes place.