Pd-based eye-readable H2 sensors: Principles, developments, and perspectives

Abstract

Hydrogen gas is considered as the ultimate energy carrier to solve the energy crisis, but safely handling hydrogen energy relies on the development of high-performance hydrogen sensors. Compared with widely investigated electric sensors, eye-readable hydrogen sensors (EHSs) have the advantage of higher safety coefficient and lower cost. Therefore, EHSs are more promising to provide basic sensing services for broader application scenarios in daily life, and they have attracted ever-increasing attention recently. However, comprehensive summaries of recent developments in EHSs are rarely reported. In this review paper, three types of Pd-based EHSs with the sensing mechanisms of localized surface plasmon resonance (LSPR), mechanical deformation, and PdO reduction are presented. The development, working principles, sensing performances, and relative merits of each type of EHS are summarized and discussed. This review not only attempts to expound the present strategies for fabricating EHSs, but also aims to inspire the design of more ingenious sensors to pursue higher sensing performance and promote further development in this field. Furthermore, a perspective and some unsolved challenges in EHSs are discussed in the end.