Coordination organic framework of phthalocyanine with carbon nanotubes for elevating oxygen evolution reaction

The designing and development of efficient, affordable, and effective electrocatalysts for the oxygen evolution reaction (OER) is crucial for advancing sustainable water-splitting technologies. In this study, coordination metal organic framework of cobalt tetracarboxylicacid phthalocyanine (CoTCPc) is synthesized using a standard conventional method and then combined with multi-walled carbon nanotubes (MWCNTs) through a simple physical grinding technique to produce a CoTCPc/MWCNT composite catalyst. The successful synthesis and structural characteristics of CoTCPc and the composite are confirmed through extensive physicochemical analysis, including Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, Brunauer–Emmett–Teller (BET) surface area, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and transmission electron microscopy (TEM). Electrochemical studies revealed that the CoTCPc/MWCNT hybrid catalyst showed significantly improved performance compared to its individual components and bare nickel foam (NF). Remarkably, the Ni/CoTCPc/MWCNT achieved a low overpotential of 360 mV at 100 mA cm − 2 , outperforming pristine CoTCPc (470 mV), MWCNT (480 mV), and benchmark RuO 2 (400 mV) at the same current density. Additionally, the CoTCPc/MWCNT catalyst demonstrated enhanced reaction kinetics with a reduced Tafel slope of 94 mV dec − 1 , compared to CoTCPc (146 mV dec − 1 ), MWCNT (137 mV dec − 1 ) and bare NF (170 mV dec − 1 ). The improved performance is attributed to enhanced charge transfer and better dispersion of active sites facilitated by the conductive MWCNT network. Moreover, the catalyst showed stable operation for over 35 h during chronopotentiometric testing at a current density of 100 mA cm − 2 . This research work presents a simple and scalable approach to boost the electrocatalytic performance of molecular cobalt phthalocyanine systems by integrating them with conductive carbon supports, offering a promising strategy for efficient OER electrocatalysis.