Yunqing Zhu,Sixiang Mao,Tian Wang,Fan Pan,Kejing Zhang,Shanshan Yu,Chuanyi Wang
Electrochemical nitrate reduction reaction (eNO 3 RR) technology offers a sustainable approach for ammonia synthesis due to its high efficiency and environmental compatibility. However, the complex multi-electron reduction process limits catalytic activity and selectivity. Herein, a tandem catalytic system is designed to address this challenge. A Cu 0 /P 2 Mo 18 /CF composite electrode, featuring copper (Cu) nanoparticle- modified P 2 Mo 18 nanocolumns, was prepared via one-step hydrothermal synthesis. The as-fabricated electrode delivers outstanding electrocatalytic performance toward eNO 3 RR. At a potential of −0.7 V vs. RHE, the nitrate (NO 3 − ) removal efficiency and ammonia (NH 3 ) selectivity reach 99% and 91%, respectively, alongside a high NH 3 yield of 666.6 μg·h −1 ·cm −2 . Moreover, the electrode retains superior catalytic activity and stability after 30 consecutive cyclic tests. The superior performance stems from the cascade effect between Cu 0 /Cu + on copper nanoparticles and P 2 Mo 18 . Cu 0 /Cu + facilitates rapid NO 3 − adsorption and reduction to nitrite (NO 2 − ), while electron-rich [P 2 Mo 18 O 62 ] 6− and acidic sites selectively reduce intermediates to NH 3 . In situ characterization further reveals that the reaction pathway proceeds as follows: *NO 3 − → *NO 2 − → *NO→*N → *NH → *NH 2 → *NH 3 . This work establishes a polyoxometalate-based cascade catalytic system, providing a novel strategy for designing efficient electrocatalysts for selective nitrate-to-ammonia conversion.
Dopamine (DA) in bovine serum served as a vital physiological biomarker for evaluating livestock health status and conducting translational biomedical research. Accurate and rapid detection of DA was therefore essential for agricultural breeding monitoring and clinical biological analysis. In this work, a novel Hemin@P 2 Mo 18 nanocomposite with peroxidase-mimicking activity was successfully prepared via a facile, green solvent-free grinding strategy. The introduction of water-soluble H 6 P 2 Mo 18 effectively suppressed the aggregation of free hemin molecules and yielded solid-phase Hemin@P 2 Mo 18 . Relative to natural peroxidases, the synthesized Hemin@P 2 Mo 18 featured convenient recovery and excellent reusability. Given the excellent peroxidase-mimicking activity of Hemin@P 2 Mo 18 , a sensitive and selective colorimetric platform was constructed for DA detection. Moreover, the proposed approach showed high selectivity against common interfering substances and excellent stability under different conditions. It was successfully applied to the quantitative determination of DA in bovine serum samples with satisfactory recovery rates ranging from 96.8% to 100.2%. This study provided a green and efficient solvent-free grinding synthesis strategy for high-performance POM-based nanozymes. It also offered a feasible and practical approach for rapid biomarker detection in complex biological matrices, which showed great application potential in veterinary monitoring and biosensing analysis. Graphical abstract
The schematic representation of the synthesis of Hemin@P 2 Mo 18 and the dual-mode detection of dopamine.
Yandi Liu,Yu-Yang Han,Sha Lu,Yingjiao Wu,Juan Li,Xiaoyi Sun,Jun Yan
Photothermal therapy (PTT) is a powerful strategy for cancer treatment with minimal invasiveness but still limited by lack of long-term efficacy against tumor recurrence and toxicity concerns about the slow biodegradability of the PTT agents. Herein, an injectable hydrogel platform (R848/POM@GG) of gellan gum co-loaded with Dawson-type {P2Mo18} polyoxometalate (POM) and Toll-like receptors agonist resiquimod (R848) is developed for combinational photothermal-immunotherapy of cancer. The POM-based gellan gum hydrogel (POM@GG) exhibits high photothermal conversion efficiency (63.1%) at a safe power density of 0.3 W cm−2 and good photostability during five cycles. By further incorporation of R848, the obtained R848/POM@GG exerts synergetic photothermal-immunotherapy on solid tumors, giving a high tumor inhibition rate of 99.3% and negligible lung metastases in the breast cancer mice models. A strong antitumor immune system with significantly elevated TNF-α, IL-2, and IL-6 levels is activated by R848. Additionally, the POM clusters gradually degrade to nontoxic molybdate in the physiological environment. Overall, the injectable hydrogel platform of R848/POM@GG has great translational potential for localized antitumor treatments.
危险品化学品经营许可证（带存储）