I doubt that graphite could be a reference electrode. Give more details.

From Saima: "I used Graphite in a three electrode system along with Platinum as a counter electrode and my material as a working electrode in a PEC system?

actually im working on a photoelectrochemical water splitting cell,using different metaloxides as a working electrode."

(from: https://www.researchgate.net/post/I_used_Graphite_in_a_three_electrode_system_along_with_Platinum_as_a_counter_electrode_and_my_material_as_a_working_electrode_in_a_PEC_system )

I maintain my previous answer; you need a true reference electrode. Choose one that is appropriate for use in alkaline solution (not one based on AgCl).

Dear Saima Qureshi,

graphite cannot be used as reference electode. His potential depends on the speaces in the solutions. For example, in the oxygen containing electrolyte potential will be 0,2 V, but vs for example saturated calomel electrode.