The use of polydopamine as a nitrogen containing precursor to generate catalytically active nitrogen-doped carbon (CNx) materials on carbon nanotubes (CNTs) is reported. These N-doped CNx/CNT materials display excellent electrocatalytic activity toward the reduction of triiodide electrolyte in dye-sensitized solar cells (DSSCs). Further, the influence of various synthesis parameters on the catalytic performance of CNx/CNTs is investigated in detail. The best performing device fabricated with the CNx/CNTs material delivers power conversion efficiency of 7.3%, which is comparable or slightly higher than that of Pt (7.1%) counter electrode-based DSSC. These CNx/CNTs materials show great potential to address the issues associated with the Pt electrocatalyst including the high cost and scarcity.