An active catalyst system for proton reduction composed of a bipyridyl platinum complex and a polymer membrane

Abstract

Electrocatalysis for the H+ reduction with bis(2,2′-bipyridyl) Pt complex (Pt(bpy)22+) incorporated in a polymer matrix was studied. When the cyclic voltammogram (CV) was measured at a basal-plane pyrolytic graphite (BPG) electrode coated with a Nafion® (Nf) membrane incorporating Pt(bpy)22+ (denoted as BPG/Nf[Pt(bpy)22+]), a remarkable growth of the cathodic current due to H+ reduction was observed below –0.4 V (vs. Ag/AgCl) in a repeated scanning. A much higher amount of H2 was obtained with the system BPG/Nf[Pt(bpy)22+] than by the conventional Pt-black. The XPS spectrum of Nf[Pt(bpy)22+] showed the formation of zero-valent Pt after the electrochemical process, indicating that H+ reduction begins to take place after formation of the catalytically active species. This work shows that a highly active catalyst system for H+ reduction can be fabricated from a noble metal complex and a polymer matrix.