Enhancing the efficiency of electron conduction in spray-coated anode of photoelectrochemical cell using oOxygenated multi-walled carbon nanotubes

A multiwalled carbon nanotube (MWNT) was physically cured with oxygen plasma treatment, and the as-prepared oxygenated MWNT (OMWNT) was incorporated into TiO₂ nanopowders to prepare a spray-coatable OMWNT-TiO₂ composite suspension. The composite layer was directly formed on a fluorinated tin oxide surface by spray coating and served as a photoanode of a photoelectrochemical cell (PEC). The cell performance was optimized in terms of the plasma treatment time and compared with a conventional PEC, showing 37% increased energy conversion efficiency. The efficiency improvement confirmed by the electrochemical impedance spectra was related to the reduced charge-transfer resistance and efficient electron transport through the OMWNT network.