Porous Organic Polymer-Derived Carbon Composite as a Bimodal Catalyst for Oxygen Evolution Reaction and Nitrophenol Reduction

Ethylene diamine-based porous organic polymer (EPOP) was synthesized, carbonized at different temperatures, and characterized. The successful formation of the triazine polymer was confirmed by Fourier-transform infrared spectroscopy, C-13, and N-15 cross-polarization magic angle spinning solid-state NMR. The two-dimensional layered architecture and graphitic nature of the samples resembled that of nitrogen-doped amorphous carbon, as confirmed by Raman, powder X-ray diffraction, and transmission electron microscopy measurements. The catalytic activity of these materials toward nitrophenol reduction and electrocatalytic activity toward oxygen evolution reaction (OER) were systematically evaluated in detail. Electrocatalytic activity toward oxygen evolution reaction was systematically evaluated by chronoamperometry and linear sweep voltammetry. Results clearly demonstrate that all of these catalysts exhibit good OER activity and excellent stability. Among all catalysts, EPOP-700 showed better OER activity, as reflected by its onset potential and current density, comparable with that of the metal-based OER catalysts and better than that of metal-free catalysts. Further, their catalytic activity toward the reduction of 4-nitrophenol to 4-aminophenol was tested with NaBH4; although all of these catalysts showed good catalytic activity; EPOP-800 displayed better catalytic activity.