If you have MWCNT powder, first disperse in ethanol for 1 h, followed by taken it in to motor pestel and wait until half the amount evaporates, then add 20 or 40wt% PEG solution dropwise while grinding.
Grinding should be continued till get paste. The attained paste you can use for doctor blade coating on FTO.
I think the paste for doctor blade must contain a binder such as PVDF or ethyl cellulose to enhance the adhesion of CNT on the FTO electrode. It also needs a viscous solvent to facilitate the coating process such as terpinol (for ethyl cellulose) or NMP for PVDF.