Indeed, the bias potential should play an important role in photoelectrochemical
CO2 reduction under UV–vis radiation. During
photoelectrolysis in slightly alkaline solution, irradiation of the
catalyst surface should generate electron–hole (e/h+) pairs, so
that the excited electrons in the conduction band migrate to the
surface and reduce CO2. The presence of copper species on the electrode
should actually improve CO2 reduction significantly [10,27],
accounting for the results presented in