A novel, one-step
protocol for the selective synthesis of W
2
C nanoparticles
from phosphotungstic acid (H
3
PW
12
O
40
), a low-cost and commercially available tungsten
compound, was developed. The nanoparticles had diameters of 1–50
nm and were dispersed on a carbon substrate. The W
2
C nanoparticles
were prepared by a simple operation sequence, involving impregnation
of carbon black with H
3
PW
12
O
40
followed
by calcination at 1000 °C. X-ray diffraction study revealed the
selective formation of the W
2
C phase in the samples prepared,
whereas the tungsten carbide (WC) phase was present in the control
prepared from H
2
WO
4
. Stable W
2
C nanoparticles
were obtained using this method owing to the presence of phosphate
at the interfaces between the W
2
C nanoparticles and the
carbon substrates, which inhibited the diffusion of carbon atoms from
the carbon substrates to the W
2
C nanoparticles, leading
to the formation of WC. The W
2
C nanoparticles prepared
showed an excellent catalytic activity for the hydrogen evolution
reaction (HER), with low Tafel slopes of ∼50 mV/decade. The
HER catalytic activity was notably high, being comparable to that
of MoS
2
, which is a promising alternative to Pt. The present
method can potentially be applied to produce highly effective, low-cost,
Pt-free electrocatalysts for the HER.
Die katalytische Hydrierung einer Reihe von 1,4‐Dialkyl‐cyclohexadienen (I) und (II) wird an Raney‐ Nickel, ‐Kobalt, ‐Eisen, ‐Kupfer, an 5% Ruthenium, Rhodium, Palladium, Osmium" Iridium oder Platin auf Kohle, an Platinoxid und Platinschwarz untersucht, und es werden die Mengenverhältnisse zwischen den verschiedenen Reaktionsprodukten (III)‐(VIII) an den verschiedenen Katalysatoren bestimmt.
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