There are many (simple[1] and/or complicated[2]) possible reasons behind some of the perplexing non closed CV loops.

1) Can you show some CV loops, using most of the rates (V/s) in a diagnostic CV-rates' list[3] (V/s) ?

2) Do you apply a 2 (or 3) electrodes' configuration cell, for the case of your non closed CV loops ?

3) Can you say what is your cell ?

1. Very high CV-rates in your case study.

2a. https://en.wikipedia.org/wiki/Passivation_(chemistry) https://en.wikipedia.org/wiki/Corrosion_inhibitor https://floridadep.gov/water/source-drinking-water/content/inorganic-contaminants

2b. Anion insertion enhanced electrodeposition of robust metal hydroxide/oxide electrodes for oxygen evolution https://www.nature.com/articles/s41467-018-04788-3

2c. Electrodeposition: A Technology for the Future https://www.electrochem.org/dl/interface/spr/spr06/spr06_p32-35.pdf

https://www.sciencedirect.com/topics/chemistry/electrodeposition-of-metals

3. A proposal diagnostic CV-rates' (small) list:= [0.001, 0.01, 0.10, 1.00, maximum] (V/s)

This is 2-electrode assembly in which NiCo2S4@SiO2-C as working electrode and Carbon nanotube paper (CNP) as -ve electrode in 6M KOH electrolyte. But i have take the 1st cycles at each sweep rate such as 5, 10 and 30 mV/s. As we know that, the 1st cycle is usually not stable and not closed untill we could run 2-3 cycles

The very slow (mixed and perplexing carriers') kinetics due to the complex varieties[1] of SiO2[2] (in "SiO2-C") is the main reason behind your non closed CV[3] loops' issue.

However, such a very slow kinetics' issue (in "SiO2-C") might be a milestone (as an educational seed) to remodel your academic studies, with a little help from your supervisor; it 'follows' that an issue might be a new door for more challenging directions.

1. Silica has three main crystalline varieties: quartz, tridymite, and cristobalite. https://pubchem.ncbi.nlm.nih.gov/compound/Silica

2. Silica and its allotropic forms. Contribution to study of their use in dentistry Article [Silica and its allotropic forms. Contribution to study of t...

3. A new-modified (for your special case) proposal (diagnostic for VERY slow Silica-kinetics) CV-rates' (small) list:= [0.01, 0.10, 1.00] (mV/s)

Dear loanis Samaras, Hope so you are doing fine. I am working on Oxygen evolution reaction. I am performing CV in non faraday region but my CV loop is not closed. Catalyst doesn't remove from the surface during OER. The electrolyte is freshly made 13.6pH. There are no bubbles on the surface of electrolyte.

What could be more technical reason behind this open loop

CV ? As per my observation, my catalyst is reconstructing into oxy(hydroxide) phase. I have performed 15CV cycles to reconstruct the catalyst and than do CV in non farady region. I think it is because of the formation of oxy(hydroxide) phase. Please give your valuable suggestions.