This work presents a unique (EU patent pending no EP21196739.3), approach to fabricate nanoporous diamond morphology using molten salt thermal etching (MSTE) at a moderate temperature (450 °C) of boron-doped nanocrystalline diamond. The developed one-step method is simple, environmentally friendly, inexpensive, and provides nanoporous diamond electrodes with nearly unlimited Z-depths. Moreover, it is also applicable to non-conductive diamond films. The appropriate etching mechanism is attributed to the preferential etching of sp2 carbon phases localized at the grain boundaries by MSTE-generated highly oxidizing species. The fabricated porous electrodes show an increase in the electrochemical active area (15%) and 49 times higher capacitance than the pristine (non-porous) material, making them promising materials to use as sensors for electroactive species and for supercapacitor applications.
