• It looks like you're asking about converting potentials referenced to the ferrocene/ferrocenium (Fc/Fc⁺) redox couple to the reversible hydrogen electrode (RHE) scale. Here's a short explanation of the general process:
• Understand the Reference Potential Difference:The Fc/Fc⁺ redox couple is typically referenced in a non-aqueous solvent like acetonitrile or dichloromethane. Its potential in aqueous solutions is often reported as ~0.63 V versus the normal hydrogen electrode (NHE), but this value can vary slightly depending on solvent and electrolyte.
• Conversion Formula: To convert Fc/Fc⁺ potential to RHE, use the following equation:ERHE=EFc/Fc⁺+(EFc/Fc⁺ vs NHE)+(0.059×pH)E_{\text{RHE}} = E_{\text{Fc/Fc⁺}} + (E_{\text{Fc/Fc⁺ vs NHE}}) + (0.059 \times pH)Here:EFc/Fc⁺ vs NHEE_{\text{Fc/Fc⁺ vs NHE}} is the Fc/Fc⁺ potential versus NHE, often ~0.63 V in water. 0.059×pH0.059 \times \text{pH} accounts for the pH-dependent shift of the RHE scale.
• Double-Check Experimental Values: It's best to confirm the EFc/Fc⁺ vs NHEE_{\text{Fc/Fc⁺ vs NHE}} value in your specific solvent and setup.

The issue is that RHE is for water, not acetonitrile. It'd be better to convert to something in acetontrile... see this paper: Article Conversion constants for redox potentials measured versus di...

This paper goes over RHE vs other things in water: Article The Standard and Reversible Hydrogen Electrodes: Theory, Des...