N-doped nanoporous carbon as efficient catalyst for nitrobenzene reduction in sulfide-containing aqueous solutions

Metal-free N-doped porous carbon (NC) materials have been demonstrated to be promising catalysts in contaminated environment remediation. Two NC materials (NC-I and NC-2) were prepared by sal-gel routes. Their catalytic properties were investigated for the reduction of nitrobenzene (NB) in sulfide containing aqueous solution. Both NC-1 and NC-2 can efficiently catalyze the reduction of NB to aniline (AN) under ambient conditions, but also can be reused for more than 5 times. The reaction fits excellently to the pseudo-first-order kinetic. Compared with NC-1 material, NC-2 shows much higher removal efficiency (rate constant kobs: 0.283 h(-1) vs. 2.50 h(-1)). The important features of NC material, including high specific surface area, suitable surface functional groups (especially nitrogen-containing groups), and enhanced electron transfer ability, should be mainly factors for its excellent catalytic activity. This work demonstrates that N-doped carbon materials have great potential for degradation of NB to AN in the natural aquatic environment. (C) 2016 Elsevier Inc. All rights reserved.