Correlation between composition and hydrogen storage behaviors of the Li2NH-MgNH combination system

Controlled-Release Electrochemiluminescence Biosensor with Strong Self-On Effect by a Multiple Signal Amplification Strategy for Trace Detection of Prostate-Specific Antigen

The enhancement of sensitivity in biological analysis detection can reduce the probability of false positives of the biosensor. In this work, a novel self-on controlled-release electrochemiluminescence (CRE) biosensor was designed by multiple signal amplification and framework-enhanced stability strategies. As a result, the changes of the ECL signal were enhanced before and after the controlled-release process, achieving sensitive detection of prostate-specific antigen (PSA). Specifically, for one thing, Fe3O4@CeO2-NH2 with two paths for enhancing the generation of coreactant radicals was used as the coreaction accelerator to boost ECL performance. For another, due to the framework stability, zeolitic imidazolate framework-8-NH2 (ZIF-8-NH2) was combined with luminol to make the ECL signal more stable. Based on these strategies, the constructed CRE biosensor showed a strong self-on effect in the presence of PSA and high sensitivity in a series of tests. The detection range and limit of detection (LOD) were 5 fg/mL to 10 ng/mL and 2.8 fg/mL (S/N = 3), respectively, providing a feasible approach for clinical detection of PSA.

Electrochemiluminescence Sensor with Controlled-Release Triggering Electrostatic Attraction Elimination Mechanism for Trenbolone Trace Detection

A controlled-release strategy can meet the needs of sensitive environmental monitoring for pollutants through a self-on/off mode. In this work, an electrochemiluminescence (ECL) biosensor with controlled-release triggering electrostatic attraction elimination and biomolecular stimulated response strategies was constructed to detect environmental steroid hormones sensitively. The blocked pores on the aminated mesoporous silica nanocontainers were opened by specific binding between the trenbolone (TB) antigen and the antibody. The released l-cysteine counteracted the negative charge on the MnO2 NF surface through the redox reaction between -SH and MnO2, making the electrostatic interaction between the MnO2 NFs and the Ru(dcbpy)32+ disappear. Ru(dcbpy)32+ released an ECL signal on the electrode, thus completing the controlled-release triggering electrostatic attraction elimination strategy. In addition, with the TB antibody as the target and the competition strategy between the TB antigen and the standard substance, the constructed controlled-release ECL biosensor was used to detect the TB standard substance. Moreover, MnO2 NFs as the substrate of the ECL biosensor increased the active specific surface area of the electrode, effectively catalyzing the production of OH• and O2•-, thus endowing the ECL biosensor with coreactant-catalytic enhancement characteristic and further improving its ECL performance. This sensitive signal response brought about a low limit of detection of 2.53 fg/mL for the constructed ECL biosensor, which contributed a feasible idea for efficient trace analysis of pollutants in the environment.

Hydrogen Pressure-Dependent Dehydrogenation Performance of the Mg(NH2)2-2LiH-0.07KOH System

The Mg(NH₂)₂-2LiH system with KOH additive is a promising high-capacity hydrogen storage material in terms of low dehydrogenation temperatures, good reversibility, and excellent cycling stability. Various mechanisms have been reported to elucidate the reasons for the K-containing additive improving the hydrogen storage performance. Herein, the dehydrogenation performance of Mg(NH₂)₂-2LiH-0.07KOH is found to be strongly associated with hydrogen pressures. The Li₂K(NH₂)₃ and KH produced from the reaction between KOH, LiH, and Mg(NH₂)₂ in the ball milling process are converted into Li₃K(NH₂)₄, MgNH, and LiNH₂ in the heating dehydrogenation process under Ar carrier gas or very low hydrogen pressure, exhibiting a two-peak dehydrogenation process. For the sample under high hydrogen pressure, Li₂K(NH₂)₃ can react with LiH to convert into Li₃K(NH₂)₄ and further to form KH and LiNH₂ in the heating process, showing a one-peak dehydrogenation process under 5 bar hydrogen. The hydrogen pressure-dependent reactions of K-containing additives in the Mg(NH₂)₂-2LiH system lead to a different hydrogen storage performance under different dehydrogenation conditions.

Hierarchical porous Li₂Mg(NH)₂@C nanowires with long cycle life towards stable hydrogen storage

The hierarchical porous Li₂Mg(NH)₂@C nanowires full of micropores, mesopores, and macropores are successfully fabricated via a single-nozzle electrospinning technique combined with in-situ reaction between the precursors, i.e., MgCl₂ and LiN₃, under physical restriction upon thermal annealing. The explosive decomposition of LiN₃ well dispersed in the electrospun nanowires during carbothermal treatment induces a highly porous structure, which provides a favourable way for H₂ delivering in and out of Li₂Mg(NH) nanoparticles simultaneously realized by the space-confinement of the porous carbon coating. As a result, the thus-fabricatedLi₂Mg(NH)@C nanowires present significantly enhanced thermodynamics and kinetics towards hydrogen storage performance, e.g., a complete cycle of H2 uptake and release with a capacity close to the theoretical value at a temperature as low as 105°C. This is, to the best of our knowledge, the lowest cycling temperature reported to date. More interestingly, induced by the nanosize effects and space-confinement function of porous carbon coating, a excellently stable regeneration without apparent degradation after 20 de-/re-hydrogenation cycles at a temperature as low as 130°C was achieved for the as-prepared Li₂Mg(NH)₂@C nanowires.