Cobalt(ii) ions and cobalt nanoparticle embedded porous organic polymers: an efficient electrocatalyst for water-splitting reactions

Development of a highly efficient electrocatalyst for the water-splitting reaction is essential and in this regard, the use of earth-abundant metal catalysts offers several advantages such as improved performance, cost-efficiency,etc.Recent studies have shown that the fabrication of transition metal/metal oxide nanoparticle supported carbon materials exhibit similar performances to that of bare metal/metal oxide nanoparticles. Herein, we report the preparation of an ethylenediamine interconnected triazine based porous organic polymer (EPOP) modified with Co2+(Co-EPOP) and Co nanoparticles (Co-EPOP-300,Co-EPOP-500andCo-EPOP-HT)viaanchoring under different conditions. The amine groups on the EPOP polymer were used as ligands and as stabilizers for Co(2+)and Co nanoparticles respectively. XRD and TEM analysis indicated that theCo-NPs covered a homogeneous polymer matrix. The electrocatalytic activities of Co2+/CoNP modified POPs were evaluated under standard OER and HER conditions and were compared with that ofCo-NPs without polymer support. Amongst the electrocatalysts, theCo-EPOP(Co(2+)anchored EPOP) sample exhibited bifunctional activity towards both the OER and HER with onset potentials of 1.638 and -0.173 V respectively. Further, theCo-EPOPcatalyst showed lower Tafel slope values compared to other catalysts. Both OER and HER performances are comparable with those of reported Co based nanocatalytic systems.