Green Chemistry: Boosting the Catalytic Performance of Ru Nanoparticles on the Cleavage of β-O-4 Linkage in Lignin by Doping Mo
Puyi Lei, Jiali Zhang, Wenzhuo Shen, Min Zhong and Shouwu Guo*
Abstract：Ru nanoparticles doped with Mo on reduced graphene oxide (RuMo/rGO) are prepared through synchronous reductions of RuCl3, MoCl5, and graphene oxide in the work. The compositions, morphologies, and structures of as-prepared RuMo/rGO composites are fully characterized. Their catalytic properties in oxidative cleavages of β-O-4 linkages in lignin model compounds and lignin are explored. It is illustrated that with O2 as oxidant the RuMo/rGO show overall better catalytic performance in the oxidative cleavage of β-O-4 linkage than the catalysts, such as Ru/rGO and RuCo/rGO reported in our previous work. The catalytic mechanism is elaborated through experiments and density functional theory (DFT) calculation. Pronouncedly, we show that the as-doped Mo can effectively boost the molecular oxygen activation process and the adsorption of β-O-4 model compounds on Ru nanoparticle surface on rGO, and thus enhance the catalytic activity. It is demonstrated meanwhile that the RuMo/rGO can catalyze the depolymerization of organosolv birch lignin yielding 17.1% aromatic compounds under relatively mild conditions (100 °C, 0.3 MPa O2, 12 h, pH = 12).
https://doi.org/10.1039/D4GC00294F
