CoP/N-Doped Carbon Hollow Spheres Anchored on Electrospinning Core–Shell N-Doped Carbon Nanofibers as Efficient Electrocatalysts for Water Splitting

Abstract

In this work, a series of hybrids of CoP/N-doped carbon hollow spheres anchored on core–shell N-doped carbon nanofibers were facilely fabricated by the electrospinning technique followed by pyrolysis and phosphorization. The as-prepared hybrids exhibited greatly enhanced bifunctional electrocatalytic activities for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) compared to either moiety of CoP/N-doped carbon hollow spheres and core–shell N-doped carbon nanofibers. Especially, the optimum CoP/NCF-200 hybrid exhibited high performances and stabilities for OER in alkaline conditions and for HER in both acidic and alkaline electrolytes. The catalyst also exhibited excellent performance for overall water splitting as both anodic and cathodic catalysts in alkaline media. The density functional theory calculations suggest that the synergy between CoP and N dopants leads to higher catalytic activities for HER and OER and the C atoms between N atoms in the carbon layer are the catalytically active sites for the HER.

Urchin‐like CoP nanomaterial as an electrocatalyst for efficient hydrogen evolution reaction

“…48 The high capacitance and low impedance indicate that CoP-300-1 improves the electron transfer rate, while the higher conductivity facilitates charge transfer. 39,49,50 These results confirm that the CoP-300-1 catalyst has an efficient catalytic activity for HER. Generally, the phosphorus element center adsorbs the protons and promotes the formation of cobalthydride.…”

“…This may be attributed to the large SSA of CoP‐300‐1, resulting in a faster redox reaction process, a smaller R ct and a higher C dl 48 . The high capacitance and low impedance indicate that CoP‐300‐1 improves the electron transfer rate, while the higher conductivity facilitates charge transfer 39,49,50 . These results confirm that the CoP‐300‐1 catalyst has an efficient catalytic activity for HER.…”

“…The peaks in the XPS spectrum of the P 2p in Figure 2C at ~133.8 eV, ~130.3 eV, and ~ 129.5 eV are attributed to the P‐O, P 2p 1/2 , and P‐Co, which suggests the presence of CoP 35,38 . And the emergence of PO maybe due to the surface oxidization of CoP in the air environment 39 . The peaks of O 1s for CoP electrocatalyst at approximately 533.1 eV and approximately 133.8 eV are ascribed to the OP bond, and the peaks at approximately 532.1 eV and approximately 531.2 eV correspond to the OC and OCo bonds (Figure 2D), respectively.…”

“…35,38 And the emergence of P O maybe due to the surface oxidization of CoP in the air environment. 39 The peaks of O 1s for CoP electrocatalyst at approximately 533.1 eV and approximately 133.8 eV are ascribed to the O P bond, and the peaks at approximately 532.1 eV and approximately 531.2 eV correspond to the O C and O Co bonds ( Figure 2D), respectively. This is due to the presence of organic carbon in the organic precursor of cobalt complex.…”

Recent Advances in 1D Electrospun Nanocatalysts for Electrochemical Water Splitting

“…In this regard, a hollow structure with a large number of layered pores will provide efficient surface area, highly exposed catalytic active sites, and high porosity to improve mass transfer. [ 141–144 ] In view of the aforementioned considerations, Tong et al [ 141 ] conveniently prepared a series of CoP/N‐doped carbon hollow sphere hybrids anchored on core–shell NCNFs by electrospinning technology. According to the TEM ( Figure a,b), it can be seen that small spheres with a diameter of about 30–50 nm are uniformly dispersed on the fibers with an average diameter of 300 nm, and the fibers have a core–shell structure.…”