Figure 2. ¹H-NMR Screening of the Stc2 photo-reduction system components under multiple turnover conditions.

Photo sensitizer, sacrificial reagent, and electron mediators were screened in a sequential manner. First, photo-sensitizers were screened using sodium ascorbate as a sacrificial reagent in Tris-buffer (e.g., zinc porphyrin in trace i, eosin Y in trace ii, [Ru(bpy)₃]²⁺ in trace iii). Second, with eosin Y as the photosensitizer, sacrificial reagents were screened (e.g., Na₂SO₃ in trace iv; Na₂S₂O₄ in v; and formic acid in vi). Third, using eosin Y/Na₂SO₃ pair, additional electron mediators were screened (e.g., titanium dioxide in trace vii; CdSe quantum dots in viii; and methyl viologen in ix). More complete list is in Table S1.