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With the increasing utilization of clean energy, the development and utilization of hydrogen energy has become a research topic of great significance. Cobalt selenide (CS) is an electrocatalyst with great potential for oxygen evolution reaction (OER). In this paper, a nitrogen-doped biomass carbon (1NC@3)-based composite cobalt selenide (CS) heterojunction was prepared via a solvothermal method using kelp as the raw material. Structural, morphological, and electrochemical analyses were conducted to evaluate its performance. The electrochemical test results demonstrate that the overpotential of the CS/1NC@3 catalyst in the OER process was 292 mV, with a Tafel slope of 98.71 mV·dec−1 at a current density of 10 mA·cm−2. The electrochemical performance of the CS/1NC@3 catalyst was further confirmed by theoretical calculations, which revealed that the presence of the biomass carbon substrate enhanced the charge transport speed of the OER process and promoted the OER process. This study provides a promising strategy for the development of efficient electrocatalysts for OER applications. [ABSTRACT FROM AUTHOR]

The uniform growth of NiSe nanocrystals on iron-doped XC-72 carbon (NS/XC-Fe) was achieved through a solvothermal method. Benefiting from the introduction of iron and the construction of heterogeneous interfaces, NS/XC-Fe exhibits outstanding catalytic activity for both OER and HER under alkaline conditions. Density Functional Theory (DFT) calculations indicated that the introduction of iron optimized the catalyst's H adsorption capability, while the construction of heterogeneous interfaces lowered the energy barrier of the rate-determining step. [Display omitted] • The loading of NiSe nanocrystals on iron-doped XC-72 carbon (NS/XC-Fe) was achieved through a straightforward solvothermal method. • Benefiting from the synergistic effects of metal coordination and the construction of heterogeneous interfaces, NS/XC-Fe demonstrates excellent catalytic activity for both the OER and the HER in an alkaline electrolyte solution. • Density Functional Theory (DFT) calculations indicated that the introduction of iron optimized the catalyst's H adsorption capability, while the construction of heterogeneous interfaces lowered the energy barrier of the rate-determining step. Developing efficient, economical, and resource-abundant dual-function electrocatalysts for water splitting is crucial. In this study, uniform growth of NiSe x nanocrystals on Fe-doped XC-72 carbon (NS/XC-Fe) was achieved through a solvothermal method, resulting in the formation of a composite material with outstanding performance. NS/XC-Fe exhibits excellent catalytic performance for both oxygen evolution reaction (OER) (261 mV, 10 mA·cm−2) and hydrogen evolution reaction (HER) (275 mV, 10 mA·cm−2) under alkaline conditions, owing to the introduction of iron and the construction of heterogeneous interfaces. Additionally, NS/XC-Fe exhibited excellent stability during the 24 h polarization test. Density Functional Theory (DFT) calculations indicated that the introduction of iron optimized the catalyst's H adsorption capability, while the construction of heterogeneous interfaces lowered the energy barrier of the rate-determining step. This demonstrates the significant potential of NS/XC-Fe as an electrocatalyst, providing new insights for the design and synthesis of efficient bifunctional electrochemical water splitting catalysts. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) and its alloys exhibit an excellent prospect for orthopedic clinical application due to their outstanding biodegradability and mechanical adaptability. However, the rapid corrosion rate/latent device-associated infections may lead to a failed internal fixation of Mg-based implants. Herein, a novel composite coating consisted of outer copper-doped zeolitic imidazolate frameworks-8 and inner hydroxyapatite (Cu@ZIF-8/HA) was in situ constructed on AZ31B Mg alloy via a two-step approach of hydrothermal treatment and seeded solvothermal method. The results verified that the electrochemical impedance of the obtained Cu 45 @ZIF-8/HA composite coating increased by two orders of magnitude to 6.6013 × 104 Ω·cm2 compared to that of bare Mg alloy. This was attributed to the reduced particle size of ZIF-8 nanoparticles due to the doped copper ions, which could be effectively grown in situ on the micro-nano flower-like structure of the HA-coated Mg alloy. Meanwhile, the Cu@ZIF-8/HA coating exhibited excellent antibacterial properties due to the release of copper ions and zinc ions from Cu@ZIF-8 dissolved in bacterial culture solution. The ICP results unraveled that the released concentration of copper and zinc ions could enhance the activity of alkaline phosphatase in the appropriate range during MC3T3-E1 cell culture in vitro for 7 days. This research revealed that the preparation of multifunctional metal-organic frameworks coating doped with antimicrobial metal ions via the seed layer solvothermal method was significant for studying the antimicrobial properties, osteogenic performance and corrosion resistance of Mg-based bioactive coatings. [Display omitted] • The Cu@ZIF-8/HA coating is constructed on Mg alloy via seeded solvothermal method. • The dodecahedron structural Cu@ZIF-8 is good for the delayed release of Cu2+ and Zn2+. • The coating shows good anti-corrosion, antibacterial ability and biocompatibility. [ABSTRACT FROM AUTHOR]