Imine Gels Based on Ferrocene and Porphyrin and Their Electrocatalytic Property

Abstract A series of porphyrin‐based imine gels have been synthesized via dynamic covalent gelation between 5,10,15,20‐tetra(4‐aminophenyl)‐21H,23H‐porphyrin (H 2 TAPP) derivatives and various aldehyde compounds. The porphyrin‐ferrocene imine gels based on MTAPP (M=H 2 , Ni 2+ , Co 2+ , Pd 2+ and Zn 2+ ) and ferrocene‐1,1′‐dicarbaldehyde (NA) display efficient HER, OER and ORR activities in alkaline media. Among the gels, CoTAPP‐NA shows an HER current density of 10 mA cm −2 at low overpotential of 470 mV and small Tafel slope of 110 mV decade −1 in alkaline media. CoTAPP‐NA also exhibits OER catalytic activity with low overpotential (416 mV for 10 mA cm −2 ). CoTAPP‐NA shows ability in overall water splitting in alkaline media. In addition, CoTAPP‐NA exhibits onset potential ( E p ) of 0.95 V and half‐wave potential ( E 1/2 ) of 0.84 V in 1.0 mol L −1 KOH solution for oxygen reduction. Moreover, the gel catalyst shows good stability.