Hydrogen is receiving a lot of attention from researchers as a clean energy source and one of the most promising sources of energy for the future. Detection of hydrogen before it reaches explosive conditions is a central issue in the safe use of hydrogen. Hydrogen sensors are devices that detect the hydrogen concentration in the environment and are capable of outputting an electrical signal proportional to the magnitude of the hydrogen concentration. Palladium (Pd) has become one of the preferred materials for the preparation of hydrogen sensors due to its strong hydrogen absorbing ability. In this paper, the intrinsic mechanism of hydrogen absorption by Pd metal is revealed, and the performance of various types of Pd-based hydrogen sensors is reviewed.

Li-air battery has high theoretical energy density, which is considered a powerful candidate for flexible electrical products power supply. However, there are many challenges to commercialize Li-air battery in wearable devices. For example, how to solve the problem of H₂O and CO₂ gas pollution and electrolyte volatilization caused by open structure. In addition, the construction of high efficiency flexible cathode, effective protection of anode materials and suppression of Li dendrites, and reasonable temperature control methods are all problems to be solved. At present, great progress has been made in the research of Li-air batteries, but there is still a lack of decisive breakthrough, which is due to the insufficient basic research. This review summarizes the research progress and challenges of flexible Li-air batteries in recent years for wearable devices, and prospects its future development direction.

As an efficient and low-carbon renewable energy source, hydrogen plays a strategic role in the global energy transition, particularly in the transportation sector. However, the flammable and explosive nature of hydrogen makes leakage risks in enclosed environments a core challenge for the safe promotion of hydrogen fuel cell vehicles. Catalytic combustion sensors are ideal choices due to their high sensitivity and long lifespan. Nevertheless, they face technical bottlenecks under vehicle operational conditions, such as high-power consumption caused by elevated working temperatures, slow response rates, weak anti-interference capabilities, and catalyst poisoning. This paper systematically reviews the research status of catalytic combustion hydrogen sensors for vehicle applications, summarizes technical difficulties and development strategies from the perspectives of hydrogen-sensitive material design and integration processes, and provides theoretical references and technical guidance for the development of catalytic combustion hydrogen sensors suitable for vehicle use.

With the rapid development of industrialization, the excessive use of fossil fuels has caused problems such as increased greenhouse gas emissions and energy shortages. The development and use of renewable energy has attracted increased attention. In recent years, solar heat pump heating technology that uses clean solar energy combined with high-efficiency heat pump units is the development direction of clean heating in winter in northern regions. However, the use of solar energy is intermittent and unstable. The low-valley electricity policy is a night-time electricity price policy. Heat pump heating has problems such as frosting and low efficiencies in cold northern regions. To solve these problems, an exergy analysis model of each component of a phase-change heat-storage coupled solar heat pump heating system was established. Exergy analysis was performed on each component of the system to determine the direction of optimization and improvement of the phase-change heat-storage coupled solar heat pump heating system. The results showed that optimizing the heating-end heat exchanger of the system can reduce the exergy loss of the system. When the phase-change heat-storage tank meets the heating demand, its volume should be reduced to lower the exergy loss of the tank heat dissipation. Air-type solar collectors can increase the income exergies of solar collectors.

Zinc-based MOFs exhibit significant advantages in ion detection due to their unique structure and chemical properties. They can efficiently and selectively recognize and detect specific ions, making them powerful analytical tools for applications in environmental monitoring, biomedical fields, and more. In this work, we used a simple ligand to improve the coordination environment of Zn²⁺ ions and successfully synthesized a 3D coordination compound Zn(all-bdc)(Py) MOF through a straightforward hydrothermal method at low temperature. Additionally, we explored the potential of this MOF as a bifunctional ion fluorescence probe for both cationic and anionic recognition. The results showed that this 3D porous MOF exhibited excellent recognition ability for trivalent iron ions (Fe³⁺) and potassium permanganate (KMnO₄⁻) ions due to its highly porous structures and efficient ion recognition. When iron ions were added to 500 μL and potassium permanganate ions were added to 100 μL, the fluorescence of the compound was effectively quenched, and the detection limits for these two ions were 0.95 μM and 0.13 μM, respectively. The mixed-ion experiments also demonstrated that even in the presence of similar ions, this 3D MOF still maintained good selective recognition ability, specifically identifying Fe³⁺ and KMnO₄⁻ ions. This work provides a novel synthetic strategy for the design of MOFs capable of mixed-ion recognition and detection, expanding their application potential in ion sensing and analysis.

In this paper, a new refractive index sensor based on Fano resonance is introduced. It is mainly composed of two parts: a metal–insulator–metal as a base waveguide and an annular resonant cavity with a double notch and a double convex circle as a coupling structure. The sensing characteristics of the design are investigated via finite element calculations. The influence of the remaining structure parameters on the system’s sensing performance and the relationship between the wavelength corresponding to the Fano trough and the refractive index are also investigated. Furthermore, the structure is applied to refractive index sensors, resulting in a type with a sensitivity of 2740 nm/RIU and a figure of merit of 52.69.