Electrochemical CO2 Reduction with a Heterogenized Iridium−Pincer Catalyst in Water.

Immobilization of well‐defined homogenous (electro)catalysts onto conductive supports offers an attractive strategy for designing advanced functional materials for energy conversion. In this context, this study reports (i) the introduction of a pyrene anchoring group on a PNP−pincer IrI complex previously described as a selective catalyst for the electrodriven CO2 reduction (CO2RR) into CO in DMF/water mixtures, (ii) the comparison of its CO2RR activity in DMF/water mixtures with the ones of two pyrene‐free reference complexes, and (iii) its activity in pure water after immobilization onto carbon nanotubes (CNTs). Surprisingly, in homogeneous conditions we find HCOO−, instead of CO, as the main CO2 reduction product for the three catalysts. After immobilization on CNTs, even if non‐negligible competitive proton reduction reaction is observed in fully aqueous media, the complex is still able to drive CO2RR and produce HCOO− with a significantly lower overpotential with respect to solution studies. [ABSTRACT FROM AUTHOR]