Surface Roughening of Nickel Cobalt Phosphide Nanowire Arrays/Ni Foam for Enhanced Hydrogen Evolution Activity

Abstract

Development of earth-abundant, efficient, and stable electrocatalysts for hydrogen evolution reactions (HER) in alkaline or even neutral pH electrolyte is very important for hydrogen production from water splitting. Construction of bimetal phosphides via tuning the bonding strength to hydrogen and increasing effective active sites through nanostructuring and surface engineering should lead to high HER activity. Here, ternary NiCoP nanowires (NWs) decorated by homogeneous nanoparticles have been obtained on Ni foam for a highly efficient HER property via long-term cyclic voltammetric (CV) sweeping. The electron density transfer between the positively charged Ni and Co and negatively charged P atoms, one-dimensional electron transfer channel of the NWs, and abundant active sites supplied by the nanoparticles and NWs endow the catalyst with low overpotentials of 43 and 118 mV to achieve the respective current densities of 10 and 100 mA cm together with long durability for at least 33 h in 1 M KOH. A cycled anodic dissolution-redeposition mechanism is disclosed for the formation of the NiCoP nanoparticles during the CV sweeping process. Such a surface roughening method is found to be adaptable to enhance the HER property of other phosphides, including NiP nanoplates/NF, NiCoP nanoparticles/NF, and CoP NW/NF.

Enhanced Photocatalytic Hydrogen Evolution of NiCoP/g‐C3N4 with Improved Separation Efficiency and Charge Transfer Efficiency

“…The high‐resolution P 2p spectrum (Figure a) shows that the peak binding energy at 129.5 eV is close to the binding energy of P 2p 3/2 indicating the presence of elemental P, whereas the peak at 133.3 eV could be ascribed to the oxidized phosphorus species by contact with air . For the Ni 2p region, the strong binding energy of 853.2 eV for 2p 3/2 is very close to that of metallic nickel (852.6 eV), implying the presence of partially charged Ni species (Ni n + , n 0) related to Ni−P, along with the peak at 870.8 eV (Figure b).…”

Electrospun Carbon Nanofibers Encapsulated with NiCoP: A Multifunctional Electrode for Supercapattery and Oxygen Reduction, Oxygen Evolution, and Hydrogen Evolution Reactions

“…[34] In the high-resolution spectra of C 1s (Figure 2d), the characteristic peaks located at 284.8, 286, and 288 eV can be assigned to the species of CC, CO, and OCO, respectively. [34] In the high-resolution spectra of C 1s (Figure 2d), the characteristic peaks located at 284.8, 286, and 288 eV can be assigned to the species of CC, CO, and OCO, respectively.…”

“…The uninterrupted evolution of gas bubbles and a merely slight deterioration of current density observed all the way through the completion of CA analysis ensure the highly stable nature of NiCoP/CNF900 electrode for OER activity. [34,62] Tafel slope is obtained by fitting the plot to a Tafel equation (η = b log j + a), where j represents the current density and b is the Tafel slope.…”

Multifunctional MoS 2 ultrathin nanoflakes loaded by Cd 0.5 Zn 0.5 S QDs for enhanced photocatalytic H 2 production

“…Electrochemical impedance spectra (EIS) tests were carried out with an electrochemical analyzer (CHI 760E, CH Instruments) from 0.1 Hz to 100 kHz. The potentials were modulated to V RHE by the equation E (vs RHE) = E (vs Ag/AgCl) + 0.1976 V + 0.0591 V × pH . To provide the working electrode, approximately 2‐mg sample powder was dispersed in 5 mL ethanol, and then it was spread over 2 × 2 cm 2 fluorine‐doped tin oxide (FTO) substrate before drying at 80°C for 5 hours.…”