AbstractCatalytic effects of surface groups on porous carbon electrodes are claimed in literature for the redox reactions V(II)/V(III) and V(IV)/V(V). The literature is critically analysed also in relation to work of this group. A method how to overcome the problem of assessing the electrochemically active surface area on porous electrodes is presented. Applying this method, no catalytic effects for above reactions can be substantiated. It is further pointed out that the parameters electrochemical potential and temperature need to be used to assess electrocatalysis.