Non-noble metal-nitride based electrocatalysts for high-performance alkaline seawater electrolysis

Abstract

Seawater is one of the most abundant natural resources on our planet. Electrolysis of seawater is not only a promising approach to produce clean hydrogen energy, but also of great significance to seawater desalination. The implementation of seawater electrolysis requires robust and efficient electrocatalysts that can sustain seawater splitting without chloride corrosion, especially for the anode. Here we report a three-dimensional core-shell metal-nitride catalyst consisting of NiFeN nanoparticles uniformly decorated on NiMoN nanorods supported on Ni foam, which serves as an eminently active and durable oxygen evolution reaction catalyst for alkaline seawater electrolysis. Combined with an efficient hydrogen evolution reaction catalyst of NiMoN nanorods, we have achieved the industrially required current densities of 500 and 1000 mA cm−2 at record low voltages of 1.608 and 1.709 V, respectively, for overall alkaline seawater splitting at 60 °C. This discovery significantly advances the development of seawater electrolysis for large-scale hydrogen production.

Manipulating dehydrogenation kinetics through dual-doping Co3N electrode enables highly efficient hydrazine oxidation assisting self-powered H2 production

“…25b) of the samples before and after the long-term stability test further confirmed the unchanged phase. Notably, when the potential increased to 1.7 V vs. RHE, at which the OER process should happen, the original peaks disappeared and the emerging broad peak at the range of 500~600 cm −1 could be assigned to the conversion of metal nitride to metal oxyhydroxide (from Co 3 N to CoOOH in our case), which has been broadly observed in previous reports regarding the OER electrocatalysis process 42,44,57,58 . Therefore, it can be concluded that the metal nitride itself could act as the active species for HzOR without observable surface change during the catalytic process.…”

“…5a. It can be seen that a small overpotential of 41 mV is required to achieve 10 mA cm −2 for PW-Co 3 N NWA/NF, which is only 9 mV larger than that of Pt/C (32 mV) and lower than recent reported transition-metal-nitride-based HER catalysts, such as NiCoN/C nanocages (103 mV) 27 , Co-Ni 3 N (194 mV) 42 , Ni 3 N/C (64 mV) 43 and NiMoN/NF (56 mV) 44 (see details in Supplementary Table 3). The surface area is an important factor to affect the catalytic activity, we then measured the electrochemical double-layer capacitance (C dl ) of different materials to compare the electrochemical surface areas ( Supplementary Fig.…”

Au@Co2P core/shell nanoparticles as a nano-electrocatalyst for enhancing the oxygen evolution reaction

“…Dynamic evolution like this has also been found and reported. 43 In addition, the conversion of Co-phosphate to Co-oxides/ hydroxides in alkaline OER conditions has also been previously reported. 13,20,23,27,28,38,42 However, a comparison of the published works on OER performance of Co-phosphate and Cooxides/hydroxides reveals no large differences in OER overpotential among them.…”

Nickel Ferrocyanide as High-Performance Next Generation Electrocatalyst for Urea Oxidation

“…In addition, compared to the emerging seawater oxidation, UOR can avoid chlorine gas generation because of the lower reaction potential of UOR than that for chlorine evolution reaction (E 0 = 1.36 V vs RHE). 8 Therefore, using UOR to replace OER can not only save the energy input but also reduce the contamination of urea-rich wastewater. 4,6 Compared to OER, UOR suffers from even more sluggish kinetics because of the complicated 6etransfer process, which needs high performance catalysts to decrease the overpotential to achieve an e cient device.…”