Production and properties of composite layers based on an Ni P amorphous matrix

Abstract

Composite layers Ni–P + Co, Ni–P + W and Ni–P + Ti were obtained in galvanostatic conditions, at jdep = 0.200 A cm−2. The x-ray diffraction method was used to determine the phase composition of the layers and atomic absorption spectrometry was applied to specify their chemical composition. A metallographic microscope, stereoscopic microscope and Form Talysurf-type profilograph were used for cross-section and surface morphology characterization of the layers. The behaviour of the obtained layers was investigated in the process of hydrogen evolution reaction from 5 M KOH using classical methods (voltammetry, steady-state polarization) and electrochemical impedance spectroscopy (EIS). Based on recorded steady-state polarization curves, the Tafel equation parameters for this process were determined. EIS was used to study the interfacial properties at electrode overpotential ΔE = −0.200 V. It was found that the investigated Ni–P + Co layer is characterized by increased electrochemical activity for hydrogen evolution compared to Ni–P + W and Ni–P + Ti layers. Greater activity of the Ni–P + Co layer in this process may be attributed to the developed electrode surface. The values of surface roughness factor Rf were also determined.

Efficient Hydrogen Evolution Electrocatalysis Using Cobalt Nanotubes Decorated with Titanium Dioxide Nanodots

“…To investigate the catalytic kinetics under the HER process,t he EIS measurements were carried out from 100 MHz to 0.01 Hz at an overpotential of 0.25 V. Nyquist plots of TiO 2 NDs/Co NSNTs-CFs,T iO 2 NDs-CFs,a nd Co NSNTs-CFs are shown in Figure 5c,w hich shows that the charge transfer resistance of TiO 2 NDs/Co NSNTs-CFs is smaller than those of Co NSNTs-CFs and TiO 2 NDs-CFs, indicating more favorable electrocatalytic kinetics for TiO 2 NDs/Co NSNTs-CFs.T he turnover frequency( TOF) values of TiO 2 NDs/Co NSNTs-CFs at the different potentials were also calculated and they are larger than those of Co NSNTs-CFs,T iO 2 NDs-CFs,a nd CFs as shown in Figure S16. The electrochemically active surface areas (ECSAs) of TiO 2 NDs/ Co NSNTs-CFs,T iO 2 NDs-CFs,a nd Co NSNTs-CFs were determined by measuring the double layer capacitance, [20] and Figure S17 shows that the ECSA of TiO 2 NDs/Co NSNTs-CFs is much larger than those of TiO 2 NDs-CFs and Co NSNTs-CFs.Sothe enhanced electrocatalytic activity of TiO 2 NDs/Co NSNTs-CFs compared with those of Co NSNTs-CFs,T iO 2 NDs-CFs,and CFs can be attributed to the above advantages, such as small charge transfer resistance,large TOFvalue and large ECSAs.…”

Silica–Polypyrrole Hybrids as High‐Performance Metal‐Free Electrocatalysts for the Hydrogen Evolution Reaction in Neutral Media

“…Nyquist plots for SiO 2 /PPy NTs-CFs,SiO 2 NDs-CFs,and PPy NTs-CFs (Figure 4c)s how that the charge transfer resistance of SiO 2 /PPy NTs-CFs is smaller than those of PPy NTs-CFs and SiO 2 NDs-CFs,i ndicating more favorable catalytic kinetics for the SiO 2 /PPy NTs-CFs.T he electrochemically active surface areas (ECSAs) of the SiO 2 / PPy NTs-CFs,SiO 2 NDs-CFs,and PPy NTs-CFs were determined by measuring the double-layer capacitance, [25] and Figure S14 shows that the ECSA of the SiO 2 /PPy NTs-CFs is much larger than those of the SiO 2 NDs-CFs and PPy NTs-CFs.H ere,t he enhanced catalytic kinetics and ECSA will obviously promote the catalytic activity of SiO 2 /PPy NTs-CFs.…”

Silica–Polypyrrole Hybrids as High‐Performance Metal‐Free Electrocatalysts for the Hydrogen Evolution Reaction in Neutral Media

“…Nyquist plots for SiO 2 /PPy NTs–CFs, SiO 2 NDs–CFs, and PPy NTs–CFs (Figure c) show that the charge transfer resistance of SiO 2 /PPy NTs–CFs is smaller than those of PPy NTs–CFs and SiO 2 NDs–CFs, indicating more favorable catalytic kinetics for the SiO 2 /PPy NTs–CFs. The electrochemically active surface areas (ECSAs) of the SiO 2 /PPy NTs–CFs, SiO 2 NDs–CFs, and PPy NTs–CFs were determined by measuring the double‐layer capacitance, and Figure S14 shows that the ECSA of the SiO 2 /PPy NTs–CFs is much larger than those of the SiO 2 NDs–CFs and PPy NTs–CFs. Here, the enhanced catalytic kinetics and ECSA will obviously promote the catalytic activity of SiO 2 /PPy NTs–CFs.…”