[en] Highlights: • Particulate photoelectrodes are studied by surface photovoltage spectroscopy (SPS). • Different back electrode materials are applied by means of particle transfer (PT). • The photocatalysts-back metal interface affects charge separation processes. • Surface modification with cocatalysts enhances charge separation. • SPS coupled with PT advances understanding of particulate photoelectrodes. Surface photovoltage spectroscopy (SPS) was applied to the analysis of particulate La₅Ti₂CuS₅O₇ and SrNbO₂N photoelectrodes fabricated by a particle transfer method, as a means of assessing charge separation under illumination. The critical roles of the back contact metals and cocatalyst in generating charge separation and defining various photoelectrochemical properties were confirmed. The results suggests that SPS in conjunction with particle transfer technology potentially allows the identification of the most beneficial photoelectrode components for photoelectrochemical water splitting.