Fast and scale-up synthesis of amorphous C,N co-doped mesoporous Co-based phosphates as advanced electrodes for supercapacitors and water oxidation

Abstract

Convenient and green methods to synthesize highly efficient and stable multi-functional electrode materials are the key and a challenge for the industrial application of new energy conversion devices. Herein, we have developed a general host–guest strategy to construct amorphous hetero-atom doped cobalt phosphates; in the first step, we fast synthesized large-scale 2D Co-based phosphate precursors with different organic amine guest molecules by a hydrothermal method, afterwards, we calcined these precursors at different annealing temperatures, leading to the decomposition of organic guest molecules, and consequently, we obtained amorphous C,N co-doped mesoporous Co-based phosphates during this decomposition process. Moreover, the optimal C4NCPO-450 shows bi-functional activity for the Oxygen Evolution Reaction (OER) and supercapacitor applications. Which has a low overpotential of 292 mV and a Tafel slope of 67.45 mV dec⁻¹ for the OER, and when used as an electrode material for supercapacitors, it reveals a large specific capacitance of 326 F g⁻¹@1 A g⁻¹, accompanied by a stability of 2200 charge and discharge cycles. We suppose that this method can be used to prepare other hetero-atom doped mesoporous electrode materials, which should be promising candidates in the electrochemical energy storage and conversion field.