In alkaline water splitting, transition metals (Ni, Fe) have received extensive attention, and NiFe-oxyhydroxide (NiFeOOH) is regarded as an exceptionally active electrocatalysts for oxygen evolution reaction (OER). However, maintaining the long-term stability of NiFeOOH at high current densities is challenging due to Fe segregation and catalyst degradation. Herein, this study proposes an approach to enhancing the stability of the Ni/Fe-O covalent bond by intercalating oxyanions (NO, PO, SO, and SeO) into the NiFeOOH substrate, improving its resistance to bond breakage. And the NiFeOOH-NO- electrocatalyst was found to be optimal, achieving an overpotential of 311 mV and stable performance at 1 A cm for several hundred hours. Consequently, NiFeOOH-NO exhibited a significantly improved OER stability, with a mere 3.33 % stability attenuation after 100 h, compared to 13.19 % for pristine NiFeOOH. Notably, the presence of NO in NiFeOOH effectively mitigates Fe segregation, leading to a fourfold enhancement in long-term stability relative to that of NiFeOOH without NO modification. Theoretical calculations show that the introduction of NO effectively shifts metal 3d band centers of NiFeOOH closer to the Fermi level. It is suggested that the oxyanions lead to increased strength of the Ni/Fe-O bonds, thereby inhibiting the dissolution of Fe and enhancing the stability of NiFeOOH phase. This research represents a significant advance in controlling Fe segregation to stabilize NiFe-based electrocatalysts for high-current-density water oxidation.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.jcis.2024.10.026 | DOI Listing |
J Am Chem Soc
January 2025
School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology, Beihang University, Beijing 100191, China.
The dual-site synergistic catalytic mechanism on NiFeOOH suggests weak adsorption of Ni sites and strong adsorption of Fe sites limited its activity toward alkaline oxygen evolution reaction (OER). Large-scale density functional theory (DFT) calculations confirm that Co doping can increase Ni adsorption, while the metal vacancy can reduce Fe adsorption. The combined two factors can further modulate the atomic environment and optimize the free energy toward oxygen-containing intermediates, thus enhancing the OER activity.
View Article and Find Full Text PDFSmall
November 2024
Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Jialuo Road 2019, Shanghai, 201800, P. R. China.
Nickel-based electrocatalysts are promising for industrial water electrolysis, but the dense hydroxyl oxide layer formed during the oxygen evolution reaction (OER) limits active sites accessibility and presents challenges in balancing structural stability with effective charge transfer. Based on this, an efficient in situ leaching strategy is proposed to construct grain boundary-rich catalyst structure with high charge transfer ability and a deep catalytic active layer reached >200-nm. Under OER conditions, stable sub-nano NiAl particles are embedded in Ni(Fe)OOH, originating from leaching out the unstable NiAl phase of the initial NiAl/NiAl alloy doped with Fe.
View Article and Find Full Text PDFNanoscale
December 2024
Optoelectronics Convergence Research Center and Department of Materials Science and Engineering, Chonnam National University, Yongbong-Dong, Buk-Gu, Gwangju 61186, South Korea.
During electrocatalytic water splitting, surface reconstruction often occurs to generate truly active species for catalytic reactions, but the stability and mass activity of the catalysts is a huge challenge. A method that combines cation doping with morphology control strategies and constructs an amorphous-crystalline heterostructure is proposed to achieve deep reconstruction of the catalyst during the electrochemical activation process, thereby significantly improving catalytic activity and stability. Amorphous iron borate (FeBO) is deposited on cobalt-doped nickel sulfide (Co-NiS) crystals to form ultrathin nanosheet heterostructures (FeBO/Co-NiS) as bifunctional electrocatalysts for the OER and methanol oxidation reaction (MOR).
View Article and Find Full Text PDFJ Colloid Interface Sci
February 2025
College of Science, China University of Petroleum, Qingdao 266580 China.
Charge transport and metal site stability play a critical role on realizing efficient solar water splitting in photoelectrochemical devices. Here, we investigated BiVO-based composite photoanodes (labelled as NF@PTA/2PACz/BVO) in which BiVO, [2-(9H-carbazol-9-yl) ethyl] phosphonic acid (2PACz) hole transport layers based on self-assembled monolayers (SAMs), and terephthalic acid (PTA)-functionalized NiFeOOH (NF@PTA) oxygen evolution cocatalysts (OECs) structurally similar to the OECs in natural photosystem II, were assembled sequentially. Alignment of energy levels and stabilization of metal sites can be achieved by this layer-designed structure.
View Article and Find Full Text PDFJ Colloid Interface Sci
February 2025
Shanxi Key Laboratory of Gas Energy Efficient and Clean Utilization, College of Chemical Engineering and Technology, Taiyuan University of Technology, Taiyuan, Shanxi 030024, China. Electronic address:
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!