In-situ single-phase derived NiCoP/CoP hetero-nanoparticles on aminated-carbon nanotubes as highly efficient pH-universal electrocatalysts for hydrogen evolution

Abstract

• P-doped aminated CNTs supported CoP/NiCoP hetero-nanoparticles (CoP/NiCoP@P-ACNTs) is prepared. • The in-situ phosphorization from the single phase material enables the formation of the CoP/NiCoP heterostructure. • It is demonstrated to be an efficient and stable catalyst for HER over the universal pH range. • The high catalytic activities arise from the strong electronic couplings between CoP, NiCoP, and P-ACNTs. • It can make the ΔGH* value of the CoP/NiCoP@P-ACNTs close to zero and lower the energy barrier for water dissociation. Developing an efficient catalyst for pH-Universal hydrogen evolution is of great interest. This work reports the synthesis of P-doped aminated CNTs supported CoP/NiCoP hetero-nanoparticles (CoP/NiCoP@P-ACNTs) through the in-situ phosphorization of the single phase NiCo 2 O 4 grown on the ACNTs. The in-situ phosphorization from the single phase material enables the formation of the CoP/NiCoP heterostructure, facilitating an electronic coupling between CoP and NiCoP. The CoP/NiCoP@P-ACNTs is demonstrated to be an efficient and stable catalyst for the hydrogen evolution reaction (HER) over the universal pH range. Specifically, it only needs overpotentials of 26.0, 94.0, and 76.8 mV to drive the current density of 10 mA cm −2 in the acidic, neutral, and alkaline solutions, respectively. All of these values are close to those of Pt/C and lower than those of many other catalysts reported recently. The DFT calculations indicate that the high catalytic activities of the CoP/NiCoP@P-ACNTs for the HER arise from the electronic couplings between CoP, NiCoP, and P-ACNTs. They can make the ΔG H* value of the CoP/NiCoP@P-ACNTs close to zero and lower the energy barrier for water dissociation. The CoP/NiCoP@P-ACNTs derived from the in-situ phosphorization of the single phase NiCo 2 O 4 is demonstrated to be an efficient pH-universal catalyst for the HER, which arises from the strong electronic couplings between CoP, NiCoP, and P-ACNTs.