The complete photochemical reduction of CO₂ depends on several factors related to the catalyst–electrolyte interface that need to work synergistically to form the desired products; they can be listed as (i) the existence of CO₂ molecules to be reduced and H₂O molecules (or another organic molecule) to be oxidized and provide protons, (ii) an effective catalyst to provide reductive electrons (e⁻) and oxidative holes (h⁺) to the system, (iii) available reaction sites on the catalysts to promote dehydrogenation of H₂O molecules (or another organic molecule) and hydrogenation of CO₂ molecules, (iv) an effective photoexcitation of the catalyst to generate electron–hole (e⁻/h⁺) charges, (v) the bulk, as well as (vi) surface charge separation, and (vii) interfacial catalytic reactions (CO₂ reduction and generation of protons).^1,2  The challenge in photochemical catalysis is to control those multiple features with a low recombination rate of the e⁻/h⁺ pairs, high Faradaic efficiency, and selectivity towards one target product, resulting in meaningful CO₂ reduction yields.