Photoelectrochemical and Photocatalytic Studies by Applying an Organic P-N Bilayer for the Selective Oxidation of Ammonia to Dinitrogen

Ammonia (NH3) is a pollutant that needs to be treated properly. Its oxidative degradation to dinitrogen (N-2) involves the transfer of six electrons, and thus, an active catalyst must be applied to accomplish the selective formation of N-2 from NH3. In this work, polycrystalline Pt was newly prepared on a multi-walled carbon nanotube (MWCNT) supporter, which was used as a co-catalyst by embedding it in a Nafion (R) membrane (i.e., Nf [Pt/MWCNT]). The 10 nm-sized Pt particles were well characterized by means of transmission electron microscopy and electrochemistry. We have found that an organic p-n bilayer, comprising fullerene (n-type) and phthalocyanine (p-type), works as a photoanode capable of oxidation at the phthalocyanine surface. When applying Nf[Pt/MWCNT] as the co-catalyst at the organo-bilayer, the selective NH3 oxidation was confirmed to occur stably in terms of photoelectrochemistry and photocatalysis, particularly under visible light irradiation.