Synthesis of graphene with different layers on paper-like sintered stainless steel fibers and its application as a metal-free catalyst for catalytic wet peroxide oxidation of phenol

Different layers of graphene (Gr) films are prepared on the paper-like sintered stainless steel fibers (PSSF) support with three-dimensional structure by CVD method. The effects of acetylene flow rate, deposition time, and deposition temperature on the properties of PSSF-Gr are investigated by EDS, AFM, SEM, TEM, and Raman spectroscopy, respectively. Then, the catalytic performances of PSSF-Gr with different layers of Gr films as metal-free catalysts for catalytic we peroxide oxidation (CWPO) of phenol are assessed in the continuous fixed-bed reactor. The catalytic results demonstrate that the PSSF-Gr catalyst with single layer graphene film achieves the best catalytic performance (phenol and TOC removal efficiency reach 99% and 73%, respectively) after continuously operating for 6 h. Under the treatment of the PSSF-Gr catalyst with single-layer graphene, total phenol oxidation and excellent TOC removal (maintain about 71%) have been achieved for the long-term operation (38 h). Moreover, the phenol conversion of blank experiment (without catalyst) and PSSF are around 40%, which are caused by thermal degradation and thus, the excellent catalytic activity of PSSF-Gr is ascribed to graphene. Like other Fenton's catalysts, the catalytic mechanism of PSSF-Gr catalyst in phenol degradation is also a center dot OH mechanism.