Controlled spatial distribution of noble metal catalysts on electrochemically activated carbon fibre supports

The preparation of electrocatalytic noble metal systems on carbon fibre supports is investigated in the present study. This is achieved through electrochemical activation of the carbon fibres, followed by ion exchange of the cationic components of complex noble metal salts and chemical reduction with NaBH 4, without and after thermolysis, with H 2 stream, with triethoxysilane or dimethyl-ethoxysilane, or with BuLi (CH 3CH 2CH 2CH 2Li). The best results referring to the catalytic activity of the produced systems on model electrochemical reactions are observed in the case of reduction with NaBH 4 after thermolysis. The results are correlated with those obtained by galvanostatic pulse reduction of the exchanged complex noble metal ions. The catalytic efficiency of the noble metal depositions obtained by galvanostatic pulse reduction approaches that observed on noble metal depositions received by chemical reduction with NaBH 4 after thermolysis. Chemical reduction has the advantage of the higher electrocatalytic activity, but electrochemical reduction offers the possibility of the formation of more stable catalytic layers, as well as of multiple noble metal layers of considerable thickness.