Mechanism of the photoreduction of carbon dioxide catalyzed by the benchmarking rhenium dimethylbipyridine complexes; operando measurements by XAFS and FT-IR

•Operando XAFS and FT-IR measurements of the photoreduction of CO2 by Re-complex.•The valence state of Re-center in the catalytic cycle changed as ReI → Re0 → ReII.•Clear evidence of an oxidative addition of CO2 to the Re0 center.•The key intermediates, [ReII-COO-] / [ReII-COOH]+, were detected.