Further, for the h-WS reaction to be useful from a technological perspective, not only the redox potentials of catalysts need to be properly aligned with the band energies of the absorber, but also the chemical reactions need to be fast. It is thus of paramount importance that the absorber and the catalyst have the right electronic communication so that the whole system works in a harmonious manner. An additional hurdle that needs to be handled in light-induced reactions is the fact that general catalytic reactions involving proton and electron transfers, as well as bond breaking/formation, are orders of magnitude slower than those of the light induced processes. As a result, back-electron transfer pathways become dominant and drastically reduce the quantum efficiency of the whole process, since it substantially decreases the ratio of productive vs. non-productive reactions.