a: Reaction conditions: PPE (100 mg), 200 ºC, 5 h, catalyst (20 mg), isopropanol (20 ml), stirring at 400 rpm. b: Raney nickel was commercial purchased. c: Ni@C was prepared by pyrolyzing the D-glucosamine hydrochloride at 800 °C, the generated sample was co-pyrolyzed with nickel acetate and melamine. d: Ni@NC was prepared by the same method as the Ni@N-C SAC except that melamine was absent. e: Ni@AC was prepared by immobilizing Ni species on the commercial purchased AC via a wet impregnation method. f: Pd/C was commercial purchased and the Pd loading was 5 wt%. ND: No detected.
The DFT and molecular dynamic stimulation were employed to investigate the reason why Ni@N-C SAC is superior to Ni@NC in cleavage of the C-O bond. Based on the XANES and EXAFS results, the optimized models of Ni@N-C SAC and Ni@NC were established using VASP software (Figure 5).