Core–shell TiC/C-QANFAs are produced directly on a Ti6Al4V substrate by a simple thermochemical process that does not require a metal catalyst or template. The nanostructured arrays show Nernstian behavior and fast electron-transfer kinetics in the electrochemical reactions of Fe(CN)₆^3−/4− and demonstrate high selectivity and sensitivity in the simultaneous detection of AA, DA, and UA.