Highly Durable Chemoresistive Micropatterned PdAu Hydrogen Sensors: Performance and Mechanism
Yeong Jae Kim, Seonyong Lee, Sungkyun Choi, Tae Hoon Eom, Sung Hwan Cho, Sohyeon Park, Sung Hyuk Park, Jae-Young Kim, Jae-Young Kim, Jaehyun Kim, Jaehyun Kim, Gi Baek Nam, Jung‐El Ryu, SeonJu Park, Soo Min Lee, Gun‐Do Lee, Jihyun Kim, Jihyun Kim, Ho Won Jang
Abstract
Hydrogen (H 2 ) is a promising alternative energy source for Net-zero, but the risk of explosion requires accurate and rapid detection systems. As the use of H 2 energy expands, sensors require high performance in a variety of properties. Palladium (Pd) is an attractive material for H 2 detection due to its high H 2 affinity and catalytic properties. However, poor stability caused by volume changes and reliability due to environmental sensitivity remain obstacles. This study proposes a micropatterned thin film of PdAu with optimized composition (Pd 0.62 Au 0.38 ) as a chemoresistive sensor to overcome these issues. At room temperature, the sensor has a wide detection range of 0.0002% to 5% and a fast response time of 9.5 s. Significantly, the sensor exhibits excellent durability for repeated operation (>35 h) in 5% H 2 and resistance to humidity and carbon monoxide. We also report a negative resistivity change in PdAu, which is opposite to that of Pd. Density functional theory (DFT) calculations were performed to investigate the resistance change. DFT analysis revealed that H 2 penetrates specific interstitial sites, causing partial lattice compression. The lattice compression causes a decrease in electrical resistance. This work is expected to contribute to the development of high-performance H 2 sensors using Pd-based alloys.