The fabrication of cost-effective hydrogen evolution reaction (HER) catalyst is a critical demand for environment-friendly energy generation with the replacement of precious metal based materials. As a powerful substitute for such purpose, Keggin heteropoly acid (HPA) H3PW12O40 (PW12) was taken as a crucial precursor to form the P–W–Ni oxide nanocomposites via electrospinning method with subsequent calcination. The characterizations of scanning electron microscopy, high resolution transmission electron microscope, x-ray powder diffraction, thermogravimetric analysis, Fourier transform infrared, Raman spectroscopy, and electrochemical method illustrated that the obtained composites were constituted of tungsten oxide phosphate (W18P2O59), nickel tungstate (NiWO4), and tungsten oxide (WO3). The crystalline PW12Ni5O43.5(isogenous) obtained at molar proportion of PW12 to NiAc2 in 1:5 exhibited excellent HER properties with small Tafel slope of 57 mV/decade and low overpotential of −0.35 V. The crystalline PW12Ni5O43.5(isogenous) nanocomposite synthesized from PW12 as precursor holds more excellent HER electrocatalytic performance than that of sample fabricated from (NH4)10W12O41 and H3PO4 as precursors. This is due to the uniformity morphology of PW12Ni5O43.5/FTO (isogenous) and enhanced synergistic effect between oxide components resulted from the favoring electrospinning process with the introduction of PW12. In this paper, PW12Ni5O43.5/FTO (isogenous) ternary nanocomposite were prepared as a facile and simple process, which allows easy control, good reproducibility, and cost-effectiveness. And PW12Ni5O43.5/FTO (isogenous) have excellent HER electrocatalytic performance.
The SiO2/WO3/NiWO4 composites modified carbon nanofibers (SiWNi-CNFs) were prepared by a facile electrospinning method with following carbonization process under nitrogen atmosphere. The as-obtained SiWNi-CNFs were characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray photoelectron spectra (XPS), X-ray powder diffraction (XRD), FT-IR spectroscopy and Raman spectroscopy. As revealed by the electrochemical measurement, the SiWNi-CNFs prepared with SiW12/NiAc2 molar ratio of 1:1 presented best hydrogen evolution activity with a small Tafel slope (48 mV dec−1) among all the as-prepared samples. Notably, the as-prepared catalysts exhibit a small onset potential (0.29 V vs. reversible hydrogen electrode), high current density and excellent stability. The experimental results pointed that the SiWNi-CNFs processes more efficient hydrogen evolution properties than that other contrast samples. This is due to the SiO2/WO3/NiWO4 composite modified on the surface of carbon nanofibers can generate numerous active sites from the synergistic effect of each component. At the same time, the intimate combination of ternary oxide and carbon nanofibers can accelerate the electron transfer, enhance the stability and hinder the aggregation of active components during the carbonization. Moreover, the net-like structure stacked by carbon nanofibers should render the exposure of active sites and facilitate the mass transport for the HER process.
Novel crystalline Ni10W12Mo12P2O87 multicomponent composite oxides were synthesized through electrospinning heteropoly acid H3PMo12O40 (PMo12), H3PW12O40 (PW12) and NiAc2-contained polyvinyl alcohol aqueous solution with a PMo12:PW12:NiAc2 ratio of 1:1:10. Then, calcination is performed under mild conditions. The characterization results of the structure, composition and morphology observed from x-ray powder diffraction, thermogravimetric analysis, field-emission high-resolution transmission electron microscopy, scanning electron microscopy, Raman spectroscopy and Fourier transform infrared illustrated that multicomponent composite oxides consisted of MoO3, WO3, NiWO4, NiMoO4 and P2O5. The electrochemical method could explain that the crystalline Ni10W12Mo12P2O87 presented better hydrogen evolution properties than those fabricated from PMo12 to NiAc2 or PW12 to NiAc2 equaling to 1:5, individually, and the corresponding Tafel slope was 40 mV/decade. In addition, the presence of NiMoO4 and NiWO4 compounds was crucial to improve the electrocatalytic hydrogen evolution properties of the catalyst.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
