β-Ni(OH) nanoplatelets are prepared by a hydrothermal procedure and characterized by scanning and transmission electron microscopy, X-ray diffraction analysis, Raman spectroscopy, and X-ray photoelectron spectroscopy. The material is demonstrated to be an efficient electrocatalyst for oxygen reduction, oxygen evolution, and hydrogen evolution reactions in alkaline media. β-Ni(OH) shows an overpotential of 498 mV to reach 10 mA cm towards oxygen evolution, with a Tafel slope of 149 mV dec (decreasing to 99 mV dec at 75 °C), along with superior stability as evidenced by chronoamperometric measurements. Similarly, a low overpotential of -333 mV to reach 10 mA cm (decreasing to only -65 mV at 75 °C) toward hydrogen evolution with a Tafel slope of -230 mV dec is observed. Finally, β-Ni(OH) exhibits a noteworthy performance for the ORR, as evidenced by a low Tafel slope of -78 mV dec and a number of exchanged electrons of 4.01 (indicating direct 4e-oxygen reduction), whereas there are only a few previous reports on modest ORR activity of pure Ni(OH).
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http://dx.doi.org/10.1039/d2ra00914e | DOI Listing |
Dalton Trans
January 2025
Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, China.
During the oxygen evolution reaction (OER), metal-organic framework (MOF) catalysts undergo structural reorganization, a phenomenon that is still not fully comprehended. Additionally, designing MOFs that undergo structural reconstruction to produce highly active OER catalysts continues to pose significant challenges. Herein, a bimetallic MOF (CoNi-MOF) with carboxylate oxygen and pyridine nitrogen coordination has been synthesized and its reconstruction behavior has been analyzed.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
State Key Laboratory for Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education and College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China.
The cobalt-nitrogen-carbon (Co─N─C) single-atom catalysts (SACs) are promising alternatives to precious metals for catalyzing the hydrogen evolution reaction (HER) and their activity is highly dependent on the coordination environments of the metal centers. Herein, a NaHCO etching strategy is developed to introduce abundant in-plane pores within the carbon substrates that further enable the construction of low-coordinated and asymmetric Co─N sites with nearby vacancy defects in a Co─N─C catalyst. This catalyst exhibits a high HER activity with an overpotential (η) of merely 78 mV to deliver a current density of 10 mA cm, a Tafel slope of 45.
View Article and Find Full Text PDFNanoscale
January 2025
Centre for Nano and Soft Matter Sciences (CeNS), Shivanapura, Bengaluru 562162, India.
Bifunctional oxygen electrocatalysis is a pivotal process that underpins a diverse array of sustainable energy technologies, including electrolyzers and fuel cells. Metal selenides have been identified as highly promising candidates for oxygen electrocatalysts with electronic structure engineering that lies at the heart of catalyst design. Two-phase Fe-doped nitrogen carbon (NC)-supported nickel selenides were synthesized using a coordination polymer template.
View Article and Find Full Text PDFDalton Trans
January 2025
School of Material Science and Engineering, Hebei University of Technology, Tianjin 300130, P. R. China.
The design of acidic oxygen evolution reaction (OER) electrocatalysts with high activity and durability is the key to achieving efficient hydrogen production. Herein, we report a Cr-doped RuO (RuCrO) catalyst that exhibits good OER activity in acidic electrolytes. The doping of Cr increases the valence state of Ru, which enhances the activity of the catalyst, and a current density of 10 mA cm can be achieved at only 235 mV, which is superior to that of unmodified RuO of 299 mV.
View Article and Find Full Text PDFNanoscale Horiz
January 2025
Research & Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen, 518057, China.
Over-oxidation of surface ruthenium active sites of RuO-based electrocatalysts leads to the formation of soluble high-valent Ru species and subsequent structural collapse of electrocatalysts, which results in their low stability for the acidic oxygen evolution reaction (OER). Herein, a binary RuO/NbO electrocatalyst with abundant and intimate interfaces has been rationally designed and synthesized to enhance its OER activity in acidic electrolyte, delivering a low overpotential of 179 mV at 10 mA cm, a small Tafel slope of 73 mV dec, and a stabilized catalytic durability over a period of 750 h. Extensive experiments have demonstrated that the spillover of active oxygen intermediates from RuO to NbO and the subsequent participation of lattice oxygen of NbO instead of RuO for the acidic OER suppressed the over-oxidation of surface ruthenium species and thereby improved the catalytic stability of the binary electrocatalysts.
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