Nanostructured boron-doped diamond electrode for seawater salinity detection

•Boron doped diamond nanorod forest (BDDNF) electrode is fabricated by HFCVD.•BDDNF electrode shows high response and stability in seawater salinity detection.•Double layer capacitance (DLC) of BDDNF is 104 timeslargerthan the planar BDD.•Higher response of BDDNF compared with BDDF is derived from the enhanced DLC.•More C-O functional groups contribute to the outstanding stability of BDDNF.