Recent Advances and Challenges of Nanomaterials-Based Hydrogen Sensors

Safety is a crucial issue in hydrogen energy applications due to the unique properties of hydrogen. Accordingly, a suitable hydrogen sensor for leakage detection must have at least high sensitivity and selectivity, rapid response/recovery, low power consumption and stable functionality, which requires further improvements on the available hydrogen sensors. In recent years, the mature development of nanomaterials engineering technologies, which facilitate the synthesis and modification of various materials, has opened up many possibilities for improving hydrogen sensing performance. Current research of hydrogen detection sensors based on both conservational and innovative materials are introduced in this review. This work mainly focuses on three material categories, i.e., transition metals, metal oxide semiconductors, and graphene and its derivatives. Different hydrogen sensing mechanisms, such as resistive, capacitive, optical and surface acoustic wave-based sensors, are also presented, and their sensing performances and influence based on different nanostructures and material combinations are compared and discussed, respectively. This review is concluded with a brief outlook and future development trends.

Sustainable Development of Carbon Nanocomposites: Synthesis and Classification for Environmental Remediation

Composite materials with carbon nanotube and graphene attachments have been regarded as promising prospects. Carbon nanocomposites have gained considerable interest in different fields including biomedical applications due to its exceptional structural dimensions and outstanding mechanical, electrical, thermal, optical, and chemical characteristics. The significant advances made in carbon nanocomposite over past years along with the discovery of new nanocomposite processing technologies to improvise the functional impact of nanotube and graphene composites by providing proper methods of synthesis and improving the production of diverse composite based on carbon nanomaterials are discussed. Carbon nanocomposites are applied in various fields such as aviation, batteries, chemical industry, fuel cell, optics, power generation, space, solar hydrogen, sensors, and thermoelectric devices. The recent design, fabrication, characteristics, and applications of carbon nanocomposites such as active carbon, carbon black, graphene, nanodiamonds, and carbon nanotubes are explained in detail in this research. It is found that unlike traditional fiber composites, Van der Waals force interfacial compounds have an important effect on the mechanical performance of carbon nanomaterial-based composites.

Synthesis Methods of Obtaining Materials for Hydrogen Sensors

The development of hydrogen sensors has acquired a great interest from researchers for safety in fields such as chemical industry, metallurgy, pharmaceutics or power generation, as well as due to hydrogen’s introduction as fuel in vehicles. Several types of sensors have been developed for hydrogen detection, including resistive, surface acoustic wave, optical or conductometric sensors. The properties of the material of the sensitive area of the sensor are of great importance for establishing its performance. Besides the nature of the material, an important role for its final properties is played by the synthesis method used and the parameters used during the synthesis. The present paper highlights recent results in the field of hydrogen detection, obtained using four of the well-known synthesis and deposition methods: sol-gel, co-precipitation, spin-coating and pulsed laser deposition (PLD). Sensors with very good results have been achieved by these methods, which gives an encouraging perspective for their use in obtaining commercial hydrogen sensors and their application in common areas for society.