Chinese Journal of Structural Chemistry最新文献

Developing efficient bifunctional catalysts for urea oxidation reaction (UOR)/hydrogen evolution reaction (HER) is important for energy-saving hydrogen production. Herein, a catalyst with crystalline-amorphous heterostructure supported by NiCo alloy on nickel foam (NiCoO-MoO_x/NC) is reported for the first time. Through simple molybdenum salt etching, 2D NiCo alloy nanosheets are transformed into a unique 3D cycad-leaf-like structure with a super-hydrophilic surface. Simultaneously, the synergistic effect between crystalline NiCoO and amorphous MoO_x improves the UOR and HER activity, merely requiring 1.28 V and −45 mV potentials to reach ±10 mA cm⁻², respectively. Particularly, the UOR kinetics of NiCoO-MoO_x/NC is enhanced significantly compared to that of NiCoO/NC. The electronic structure of NiCoO is modified by MoO_x, enabling the rapid generation of NiOOH and CoOOH active species, which would accelerate the synergistic electrocatalytic oxidation of urea molecules. This work inspires the design of highly active and stable bifunctional catalysts for urea assisted H₂ production.

Flexible zinc-air batteries (FZABs) are featured with safety and high theoretical capacity and become one of the ideal energy supply devices for flexible electronics. However, the lack of cost-effective electrocatalysts remains a major obstacle to their commercialization. Herein, we synthesized a porous dodecahedral nitrogen-doped carbon (NC) material with Co and Mn bimetallic co-embedding (Co_xMn_1−x@NC) as a highly efficient oxygen reduction reaction (ORR) catalyst for ZABs. The incorporation of Mn effectively modulates the electronic structure of Co sites, which may lead to optimized energetics with oxygen-containing intermediates thereby significantly enhancing catalytic performance. Notably, the optimized Co₄Mn₁@NC catalyst exhibits superior E_1/2 (0.86 V) and j_L (limiting current density, 5.96 mA cm⁻²) compared to Pt/C and other recent reports. Moreover, aqueous ZAB using Co₄Mn₁@NC as a cathodic catalyst demonstrates a high peak power density of 163.9 mW cm⁻² and maintains stable charging and discharging for over 650 h. Furthermore, FZAB based on Co₄Mn₁@NC can steadily operate within the temperature range of −10 to 40 °C, demonstrating the potential for practical applications in complex climatic conditions.

Electrocatalytic carbon dioxide reduction reaction (eCO₂RR) represents one of the most promising technologies for sustainable conversion of CO₂ to value-added products. Although metal-organic frameworks (MOFs) can be vastly functionalized to create active sites for CO₂RR, low intrinsic electrical conductivity always makes MOFs unfavorable candidates for eCO₂RR. Besides, studies on how to regulate eCO₂RR activity of MOFs from linkers' functionalities viewpoint lag far behind when compared with the assembly of multinuclear metal-centered clusters. In this work, non-toxic bismuth(III) oxide (Bi₂O₃) was incorporated into a series of two-dimensional (2D) MOFs (ZrLX) established from Zr-oxo clusters and triazine-centered 3-c linkers with different functionalities (LX = 1–5) to give composites ZrLX/Bi₂O₃. To investigate how functionalities on linkers distantly tune the eCO₂RR performance of MOFs, electron-donating/withdrawing groups were installed at triazine core or benzoate terminals. It is found that ZrL2/Bi₂O₃ (‒F functionalized on triazine core) exhibits the best eCO₂RR performance with the highest Faradaic efficiency (FE) of 96.73% at −1.07 V vs. RHE, the largest electroactive surface (C_dl = 4.23 mF cm⁻²) and the highest electrical conductivity (5.54 × 10⁻⁷ S cm⁻¹), highlighting tuning linker functionalities and hence electronic structure as an alternative way to regulate eCO₂RR.

Currently, organic-inorganic hybrid lanthanide-incorporated polyoxometalates (POMs) have emerged as a prominent research area. Herein, we employ a simple raw material assembly method to synthesize two neoteric mixed-organic-ligand-ornamented lanthanide (Ln) incorporated selenotungstates [H₂N(CH₃)₂]₁₆Na₂[Ln₄(H₂O)₆(HPZDA)₂(HFMA)₂W₈O₂₁][B-α-SeW₉O₃₃]₄·29H₂O (Ln = Sm³⁺ (1), La³⁺ (2); H₂PZDA = 2,3-pyrazine dicarboxylic acid, H₂FMA = fumaric acid). 1 and 2 are isomorphic with the polyanions constructed from four trivacant Keggin [B-α-SeW₉O₃₃]^8– ({SeW₉}) segments and a rigid-flexible-ligand-ornamented dodeca-nuclear W–Ln heterometallic [Ln₄(H₂O)₆(HPZDA)₂(HFMA)₂W₈O₂₁]¹⁴⁺ cluster. Moreover, the solid-state fluorescence spectrum of 1 at room temperature mainly exhibits the characteristic emission peak of Sm³⁺ cations. Additionally, energy transfer from {SeW₉} to Sm³⁺ ions in 1 has been demonstrated by time-resolved spectroscopy. This work presents a feasible dual-ligand synergistic strategy for constructing novel POM derivatives and POM-based fluorescent materials.