Large-current-stable bifunctional nanoporous Fe-rich nitride electrocatalysts for highly efficient overall water and urea splitting

Abstract

Designing highly active electrocatalyst for both the oxygen evolution and urea oxidation reactions (OER and UOR) with good durability at large current density is very significant for greatly reducing the...

Strategies for designing more efficient electrocatalysts towards the urea oxidation reaction

“…Therefore, compared to acidic or neutral UOR, alkaline UOR is more promising. For alkaline UOR, owing to the intrinsic higher activities, Ni-based catalysts (Ni-containing metals, 80–84 oxides, 85–90 hydroxides, 91–97 sulfides, 98–102 phosphides, 103–105 selenides, 106–108 nitrides, 109–113 etc. ) have been more widely investigated among all transition metal-based catalysts.…”

Boosting Alkaline Hydrogen and Oxygen Evolution Kinetic Process of Tungsten Disulfide‐Based Heterostructures by Multi‐Site Engineering

“…In contrast, the Ni 2p and Fe 2p XPS spectra still show very strong peak intensity, and Ni or Fe valence states obviously shift to higher binding energies without the presence of Ni-N or Fe-N bonds after OER testing, indicating that the Ni 3 FeN nanosheets have been oxidized to NiFe oxides at the surface due to the large anodic potentials for the OER catalysis, which is consistent with our previous observations. [33] In particular, to present a direct evidence for the aforementioned points, we utilized energy-dispersive X-ray spectroscopy (EDS) to analyze the chemical compositions, finding that the post-OER samples are mainly composed of nickel iron oxides with very low N, W, and S signals (Figure S19, Supporting Information). These XPS analyses (Figure S18, Supporting Information), combined with the EDS spectrum (Figure S19, Supporting Information), confirm the inevitable conversion of the N-WS 2 /Ni 3 FeN hybrid into amorphous Ni-Fe oxides/oxyhydroxides, and the dissolution of N-WS 2 particles at the surface during the OER testing at high anodic potentials.…”

“…Consequently, the in situ formed Ni-Fe oxides/oxyhydroxides at the surface are probably the real active sites responsible for the excellent properties toward oxygen evolution. [20,33] Inspired by the exceptional catalytic performance of the N-WS 2 /Ni 3 FeN toward both the HER and OER, a device for full water splitting is assembled, in which the heterostructure is taken as both the cathode and anode (Figure 6a). Consequently, the robust catalytic performance is achieved, requiring a low cell potential of 1.5 V to reach 10 mA cm −2 (Figure 6b).…”

“…In this sense, porous architectures made of transition metal nitrides are promising candidates as ideal conductive scaffolds for anchoring WS 2 -based electrocatalysts with multifunctional sites for water dissociation, hydrogen or oxygen evolution. [32,33] In other words, hybridizing these two different components would be a promising strategy to simultaneously achieve high performance for bifunctional water splitting in base. [34][35][36][37][38] In the light of the above points, we first employed density functional theory (DFT)-based first-principles study to explore the catalytic properties of N-modified WS 2 anchored on conductive nickel iron nitride (Ni 3 FeN) surface.…”

The controlled synthesis of nitrogen and iron co-doped Ni3S2@NiP2 heterostructures for the oxygen evolution reaction and urea oxidation reaction

“…[6][7][8] Compared with traditional hydrogen production from gas, natural gas and ammonia decomposition, hydrogen production using electrolysis of water gives the largest yield (300 m 3 /H) and the operation process is simple and stable and can be fully automatic. 3,[9][10][11] It is an effective technology to convert electricity into storable H 2 fuel. Nevertheless, because of its high overpotential and high power consumption, the catalytic activity of the electrocatalytic anodic oxygen evolution reaction (OER) is low, which leads to the relatively high overall potential of the electrolytic water splitting system.…”