Dear Kamal Asghar

SHE potential is at any temperature by the definition 0.000 V.

I am not sure what you mean by " reference hydrogen electrode " - reversible hydrogen electrode?.

Er(RHE) = -0.0591pH at 25oC. So at pH 1, potential is -0.0591 V vs SHE. at pH = 10, Er(RHE) = -0.591 V vs SHE. So at pH = 10 Er(RHE) = -0.591 V vs SHE, is 0.591 vs RHE, not SHE.

Professor Branimir N. Grgur ,

Thanks for your comprehensive answer. By RHE what I mean was reversible hydrogen electrode. Are you sure that the value of 0.0059 is negative?

Yes,

By increasing pH potential becomes more negative -0.0591 V/pH vs SHE (or other reference electrodes).