Trimetallic synergistic optimization of 0D NiCoFe-P QDs anchoring on 2D porous carbon for efficient electrocatalysis and high-energy supercapacitor

Developing multi-functional and low-cost noble-metal-free catalysts such as transition metal phosphides (TMPs) to replace noble-metal is of practical significance for energy conversion and storage. However, the low-durability and the agglomeration phenomenon during the electrochemical process limit their practical applications. Herein, using metal–organic frameworks (MOFs) as the precursor and a combined strategy of gradient temperature calcination and thermal phosphorization, a 0D/2D heterostructure of NiCoFe-P quantum dots (QDs) anchored on porous carbon was successfully developed as highly efficient electrode materials for overall water splitting and supercapacitors. Owing to this distinctive 0D/2D heterostructure and the synergistic effect of multi-metallic TMPs, the NiCoFe-P/C exhibits excellent electrocatalytic activity and durability of HER (87 mV at 10 mA cm−2) and OER (257 mV at 100 mA cm−2) in the KOH electrolyte. When NiCoFe-P/C is used as the two electrodes of electrolyzed water, only 1.55 V can drive the current density to 10 mA cm−2. At the same time, our NiCoFe-P/C possessed extraordinary property for charge storage. In particular, an ultra-high energy density of 100.8 Wh kg−1 was achieved at a power density of 900.0 W kg−1 for our assembled hybrid supercapacitor device NiCoFe-P/C (2:1)//activated carbon (AC). This work may open a potential way for the design of 0D/2D hybrid multi-functional nanomaterials based on TMPs QDs.