Abstract
Hydrogen is rapidly emerging as a clean and versatile energy carrier addressing challenges of climate change and energy sustainability. With increasing energy demand and rising application of hydrogen energy, safety while harnessing hydrogen energy is a primary concern. To enhance safety, it is critical to detect hydrogen gas during its leakage which is otherwise challenging due to its colourless, odourless and inflammable nature. Hence, there is an urgent need for the development of hydrogen sensors for rapid response, maximum absorption/desorption, high selectivity, a wide dynamic range, and a low detection limit. This review provides a comprehensive analysis of emerging nanomaterials and their composites spanning from 0D to 3D for hydrogen sensing, emphasizing the underlying mechanisms. It also deliberates on the advantages and disadvantages of a wider range of advanced materials including noble metals, metal oxide semiconductors (MOS), transition metal dichalcogenides (TMD), metal organic frameworks (MOF), Xenes and MXenes pondering over hysteresis phenomenon, commonly observed as a limitation of noble metal-based hydrogen sensors. Among these emerging materials, two dimensional nanomaterials stand out as the optimal choice for hydrogen sensing due to their large surface area, exceptional electrical properties, low operating temperatures, and ease of chemical modification. Carbon-based materials, TMDs, MOFs, and MXenes have higher gas absorption capability and excellent mechanical properties, making them suitable for low/room temperature sensing and wearable sensing platforms. The review underscores the need for reliable sensing materials and presents challenges in quantitative detection of hydrogen offering future directions for research in this field.