Nickel–Cobalt Hydrogen Phosphate on Nickel Nitride Supported on Nickel Foam for Alkaline Seawater Electrolysis

Abstract

Developing high-performance non-noble bifunctional catalysts is pivotal for large-scale seawater electrolysis but remains a challenge. Here we report a sandwichlike NiCo­(HPO4)2@Ni3N/NF (denoted by NiCoHPi@Ni3N/NF) catalyst. Vertical Ni3N nanosheet arrays are first grown and supported on nickel foam, and then a bimetallic NiCoHPi coating is decorated on Ni3N nanosheets by one-step electrodeposition. The hierarchical sandwich like structure offers a large surface area and plenty of catalytic active sites, and the coupling of interconnected Ni3N and NiCoHPi accelerates the electron transfer. Moreover, the surficial hydrogen phosphate ions contribute to a proper OH– absorption capacity due to the Lewis acid–base reaction. As a result, the NiCoHPi@Ni3N/NF catalyst exhibits good OER and HER activity, requiring overpotentials of 365 mV (for OER) and 174 mV (for HER) to deliver 100 mA cm–2 in the alkaline simulated seawater electrolyte. When assembled the NiCoHPi@Ni3N/NF catalyst as both the anode and cathode, it only needs 1.86 V to reach 100 mA cm–2 in alkaline simulated seawater electrolyte. This work may inspire the design and exploration of self-supported hierarchical composite electrocatalysts for hydrogen production from the electrolysis of seawater.

Amorphous Co-Mo-B Film: A High-Active Electrocatalyst for Hydrogen Generation in Alkaline Seawater

“…The following supporting information can be downloaded at: , refs. [ 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 ] are cited in this file. Figure S1: (a) Low- and (b) high-magnification SEM images of bare NF; Figure S2: (a) Low- and (b) high-magnification SEM images of Co-B/NF; Figure S3: EDX spectrum of Co-Mo-B/NF; Figure S4: XPS survey spectrum of Co-Mo-B/NF; Figure S5: LSV curves of Co-Mo-B/NF, Co-B/NF, Pt/C, and bare NF for HER in 1 M KOH with a scan rate of 5 mV s –1 (without IR correction); Figure S6: CV curves for Co-Mo-B/NF (a), Co-B/NF (b), and bare NF (c) in the non-Faradaic capacitance current range at scan rates of 20, 40, 60, 80, and 100 mV s –1 in 1 M KOH; Figure S7: LSV curves of Co-Mo-B/NF in 1 M KOH, 1 M KOH + 0.5 M NaCl, and 1 M KOH + seawater with a scan rate of 5 mV s –1 (without IR correction); Figure S8: High-resolution XPS spectra of (a) Co 2p, (b) Mo 3d, (c) B 1s, and (d) O 1s regions for Co-Mo-B/NF after stability test in alkaline seawater; Figure S9: The Faradaic efficiency of Co-Mo-B/NF at 100 mA cm –2 in alkaline seawater; Table S1: Comparison of HER performance of Co-Mo-B/NF with recent reported electrocatalysts in alkaline freshwater; Table S2: Comparison of HER performance of Co-Mo-B/NF with recent reported electrocatalysts in alkaline seawater.…”

Corrosive engineering assistedin situconstruction of an Fe–Ni-based compound for industrial overall water-splitting under large-current density in alkaline freshwater and seawater media

“…The obtained electrocatalyst presents a flower-like morphology composed of nanosheets with rich exposed edges, which provide sufficient active sites during the electrocatalytic process. 36 Moreover, the interconnected channels accelerate the release of produced gas and the contact between the electrodes and electrolytes. 37 More morphological details can be observed in Fig.…”

Superb All‐pH Hydrogen Evolution Performances Powered by Ultralow Pt‐Decorated Hierarchical Ni‐Mo Porous Microcolumns

“…The NiMoO 4 •xH 2 O precursor grown on a slice of nickel foam (NF) is prepared by a simple hydrothermal method at 150 °C for 5 h. Commercial NF is selected as a catalyst-grow substrate since its excellent mechanical/chemical stability, porous skeleton structure, and high conductivity (Figure S1, Supporting Information). [59,60] Scanning electron microscopy (SEM) images show that smooth microcolumns with diameters between 1 and 2 µm are vertically supported on NF (Figure S2, Supporting Information). X-ray diffration (XRD) pattern in Figure S3, Supporting Information reveals the successful formation of NiMoO 4 •xH 2 O after hydrothermal reaction.…”