Self-organized macroporous thin carbon films for supported metal catalysis

An easy one step and scalable process for the synthesis of multilayer macroporous polymer and carbon films is demonstrated by using spin coated thin films of polyacrylonitrile (PAN) in N,N-dimethyl formamide (DMF) solvent followed by their carbonization. The interconnected porous carbon films were characterized by various techniques including SEM, HRTEM, Raman, XRD, BET and AFM. Phase-separation/dewetting in sub-micrometer thick films spontaneously produced a macroporous (pore diameter > 50 nm) polymer films with hole density in the range of 108–109 per cm2 and BET area of ~175 m2/g. Increased porosity can be tailored under the conditions that favor greater destabilization of the spin coated films such as reduced film thickness, higher evaporation rate and lower viscosity. Further, Ag/carbon hybrid films were prepared by incorporation of a silver salt in the solution prior to spin coating. The Ag/carbon porous films show good activity in the reduction of para-nitrophenol to para-aminophanol with sodium borohydride.