Topics in Current Chemistry (2018) 376:42
1 3
reaction (HER) (Fig. 14a, b). A mere voltage of 1.38 V was needed to reach the current of 10 mA cm
−2
in this electrolytic cell, and the excellent catalytic performance
can maintain an exceptional stability during the 25-h test (Fig. 14c). Actually, more
similar bifunctional catalysts as the Ni–Mo–O will be further described in the next
section.
4.4 Novel Nickel‑Based Compounds
Furthermore, there have been exiting a series of novel nickel-based compounds
(mainly referring to nickel-based sulfides, phosphides, selenides, etc.). Considering that these nickel-based sulfides, phosphides, and selenides have also been successfully applied in HER because of their good conductivity, excellent stability, and
superior electrochemical performance, it seems more meaningful to design them as
bifunctional catalysts for both highly efficient electrolysis of urea as well as electrochemical hydrogen production in the overall water spitting system (as shown in
Fig. 15) [106–111]. More importantly, the development of these series of catalysts
is hopeful for promoting the application of urea electrolysis in the field of future
energy storage.
Fig. 14 a Schematic diagram of the preparation of NiMoO-Ar for UOR catalyst and NiMoO-H 2 for HER
catalyst; b comparison of the cell voltage required to reach different current densities for urea electrolysis
and water electrolysis; c long-term stability test of urea electrolysis (cell voltage = 1.58 V) Reproduced
with permission from Ref. [105]
Reprinted from the journal
64
1 3
reaction (HER) (Fig. 14a, b). A mere voltage of 1.38 V was needed to reach the current of 10 mA cm
−2
in this electrolytic cell, and the excellent catalytic performance
can maintain an exceptional stability during the 25-h test (Fig. 14c). Actually, more
similar bifunctional catalysts as the Ni–Mo–O will be further described in the next
section.
4.4 Novel Nickel‑Based Compounds
Furthermore, there have been exiting a series of novel nickel-based compounds
(mainly referring to nickel-based sulfides, phosphides, selenides, etc.). Considering that these nickel-based sulfides, phosphides, and selenides have also been successfully applied in HER because of their good conductivity, excellent stability, and
superior electrochemical performance, it seems more meaningful to design them as
bifunctional catalysts for both highly efficient electrolysis of urea as well as electrochemical hydrogen production in the overall water spitting system (as shown in
Fig. 15) [106–111]. More importantly, the development of these series of catalysts
is hopeful for promoting the application of urea electrolysis in the field of future
energy storage.
Fig. 14 a Schematic diagram of the preparation of NiMoO-Ar for UOR catalyst and NiMoO-H 2 for HER
catalyst; b comparison of the cell voltage required to reach different current densities for urea electrolysis
and water electrolysis; c long-term stability test of urea electrolysis (cell voltage = 1.58 V) Reproduced
with permission from Ref. [105]
Reprinted from the journal
64