Electrocatalytic activity of sulfonated graphene oxide/conductive polymer nanocomposite film: Electrochemical and theoretical study

Investigation of electro-oxidation processes of alcohols is critical to attaining a betterunderstanding of the direct alcohol fuel cell (DAFC). Methanol is one of the interesting futurefuels for fuel cell application. Compared with other cells, the direct methanol fuel cell (DMFC)has several advantages such as high efficiency, very low polluting emissions, a potentiallyrenewable fuel source, fast and convenient refuelling, simple operation and ease of fuel storageand distribution. One of the problems still unsolved is the slow kinetics of methanol oxidation onthe fuel cell’s anode. Considerable efforts have been directed towards the study of methanolelectro-oxidation at high pH in the presence of the efficient electrocatalyst [1-2]. In this work, wehave modified a graphite electrode with sulfonated graphene oxide /POAP nanocomposite film.The modified electrode consisted of nickel ions loaded into a sulfonated graphene oxide /POAPnanocomposite in a nickel chloride solution. The prepared composite electrode exhibited goodelectrocatalytic activity toward the oxidation of methanol at a potential in which the oxidizingNi(III) species were generated. The rate of the electro-oxidation of methanol was based on acatalytic reaction between Ni(III) and methanol (EC mechanism). The voltammetric andamperometric measurements showed that the prepared nanocomposite film could be a goodalternative catalyst in fuel cells. In addition, the intra-molecular charge and energy transfer inPOAP molecular system are studied, using quantum theory of atoms-in-molecules (QTAIM).This results show that a single electro-chemical/field-effect molecular system (such as POAP)can be grouped into p-type-like/n-type-like sections (as intra-molecular semiconductor).

Keywords:

Electrocatalyst , Graphene oxide , QTAIM , Conductive polymer , Local charge/energy transfer