The electrochemical reduction behavior of nitrobenzene on platinum electrode was studied with cyclic voltammetry(CV)

chronoamperometry(CA)

constant-potential electrolysis and in-situ Fourier transform infrared spectroscopy(in-situ FTIRS)in ionic liquid(N-butylpyridinium tetrafluoroborate

BPyBF4)aqueous solution.The optimum water concentration(15 mol·L-1)was determined through analyzing the peak current and peak potential of cyclic voltammetry in different ionic liquid solutions. Constant potential electrolysis was performed in a small beaker of 10 ml at the optimum water concentration using platinum foil

graphite and platinum wire as cathode electrode

anode electrode and reference electrode

respectively.Electrolysis products were extracted with ether and determined subsequently by GC-MS and GC.In-situ FTIR spectroscopic experiments were performed on Nicolet 670 FTIR spectrometer equipped with an MCT-A detector cooled with liquid nitrogen.Working electrode was Pt electrode with its surface pressed against the CaF2 disk window to form a thin layer for IR measurements. Auxiliary electrode was Pt foil and reference electrode was saturated calomel electrode.The reference spectrum was acquired at 0 mV and sample spectra were collected on Pt cathode polarized from -100 mV to -1600 mV at a constant modulation potential(E=-100 mV).The experiment results showed that electrochemical reduction process of nitrobenzene was controlled by diffusion

the main reduction product was azobenzene and the selectivity was about 80%.The diffusion coefficient of nitrobenzene in BPyBF4-H2O was 3.1×10-7 cm2·s-1

and a suitable temperature and proper amount of water were favorable for the reduction of nitrobenzene.