Liu Lin,Yunming Xu,Yiting Han,Ruikun Xu,Tongyue Wang,Zemin Sun,Zhenhua Yan
A deep understanding of the mechanism for the spin-magnetic effect on O–H cleavage is crucial for the development of new catalysts for water oxidation. Herein, we designed and synthesized the crystalline Fe-DABDT and Co-DABDT (DABDT = 2,5-diaminobenzene-1,4-dithiol) and optimized an effective magnetic moment to explore the role of the spin-magnetic effect in the regulation of water oxidation activity. It can be found that the OER activity of the catalyst is positively correlated with its effective magnetic moment. Under the external magnetic field, Fe-DABDT with more spin single electrons has a stronger spin-magnetic response to water oxidation than Fe/Co-DABDT and Co-DABDT. The increase in OER current of Fe-DABDT is nearly 2 times higher than that of Co-DABDT. Experimental and density functional theory studies show that magnetized Fe sites could realize nucleophilic reaction, accelerate the polarization of electron spin states, and promote the polar decomposition of O–H and the formation of the O–O bond. This study provides mechanistic insight into the spin-magnetic effect of oxygen evolution reaction and further understanding of the spin origin of catalytic activity, which is expected to improve the energy efficiency of hydrogen production.
Aqueous lithium-ion batteries (ALIBs) have attracted increasing attention for their inherent safety and environmental benefits. However, the narrow electrochemical stability window of water (1.23 V) imposed by hydrogen evolution reaction (HER) and high melting point (0 °C) critically limits the energy density and low-temperature operation. In this work, we report an electrolyte design principle that water activity can be suppressed by strengthening the O–H bonds between water molecules and regulating the pH. A strong polar solvent N,N-dimethylformamide (DMF) interacts with H2O through intermolecular hydrogen bonds, thereby reinforcing the covalent O–H bonds of water. Meanwhile, KOH renders the electrolyte alkaline, inhibiting water dissociation kinetics and consequently raising the HER overpotential. The designed LD1.7W0.6–KOH electrolyte exhibits a freezing point below −82 °C and expanded electrochemical stability window of 4.3 V. The 2.5 V aqueous LiMn2O4/Li4Ti5O12 full cell delivers 2000 cycles at a rate of 6 C with a Coulombic efficiency of 99% at 30 °C and over 1950 cycles at 0 °C. This work offers atomic-level insights into alkaline HER while providing guidance for advancing low-temperature aqueous batteries by tuning the electrolyte structures.
The sp 3 hybridization of surface sulfur in metallic phase molybdenum disulfide (1T MoS 2 ) is identified as the intrinsic bottleneck for alkaline hydrogen production (HER), where their electron-saturated nature elevates the kinetic barrier for water dissociation. To overcome this limitation, a charge-buffered sulfidation strategy is reported to stabilize anionic boron (B δ− ) within 1T MoS 2 . By employing molybdenum aluminum boride as the precursor, the B δ− dopants can be efficiently preserved via the topological confinement imposed by Mo─B─Mo network. This approach also maintains the 1T phase integrity through Al-mediated electron compensation. Theoretical and experimental analyses reveal that B δ− substitution generates vertically oriented empty p z orbitals through sp 2 hybridization, which elevates orbital energy to align with molecular orbitals of water, significantly reducing the O─H cleavage barrier by over 80% compared to 1T MoS 2 . Concurrently, the B─Mo─S networks upshift adjacent sulfur 3p band centers to optimize the hydrogen adsorption path. These dual functionalities endow the p z -functionalized 1T MoS 2 with a low overpotential of −30 mV at 10 mA cm −2 , and high-current operation of 1 A cm −2 at 1.779 V in an anion-exchange membrane electrolytic cell. This work not only establishes orbital alignment as a transformative design principle for advanced electrocatalysts, but also paves a novel synthetic pathway for 1T transition metal disulfides.
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