Fig. 2. Non-covalent immobilization of porphyrin/phthalocyanine CO₂RR catalysts onto carbon-based electrodes representative of the catalysts reported in (a) an iron triphenylporphyrin bearing 6 pendant –OH groups on the ortho positions of the phenyl rings immobilized on CNTs with a pyrene group (copyright 2016, Royal Society of Chemistry);¹⁰² (b) iron tetraphenylporphyrin immobilized in a flow cell (copyright 2020 Elsevier);⁸⁶ (c) iron porphyrin–pyridine derivatives immobilized on CNTs (copyright 2020 American Chemical Society);⁷⁴ (d) cobalt chlorin adsorbed on MWCNTs on a glassy carbon electrode (copyright Royal Society of Chemistry);¹¹⁶ and (e) cobalt phthalocyanine immobilized on CNTs (copyright 2019, Nature Publishing Group).¹¹⁷.