Nanomaterials-Based High Performance Sensors for Hydrogen in Clean Energy Usage

zhili xiaoZhili Xiao
Presidential Research Professor
Department of Physics




Project Description: Hydrogen (H2)-powered cars, trucks, homes, and businesses could significantly reduce pollution and greenhouse gas emissions as well as our dependence on fossil fuels. However, H2 gas is highly volatile and, when in contact with oxygen, can become extremely flammable and highly explosive. The use of effective H2 sensors to accurately and quickly respond to H2 gas leaks and to monitor manufacturing and distribution will be crucial for the safe deployment of all H2-based applications. Two types of H2 sensors are required: sensors to monitor the quality of the hydrogen feed gas and, more importantly, sensors to detect leaks. These H2 sensors must be sensitive enough to discriminate between ambient low-level traces of hydrogen and those that are generated by a H2 leak. They must have extremely short response times to follow the fuel cell's power generation and to shut down the engine in the event of a tank rupture. Commercial sensors suffer from longer response times than the duty cycles likely needed for most applications. We have been developing fast and sensitive hydrogen sensors based on nanoscale materials. Their extremely large surface area and short hydrogen diffusion paths can dramatically enhance the sensitivity and speed of the sensors, respectively. We achieved the world’s fastest hydrogen sensors by utilizing palladium (Pd) nanoclusters in 2005, which was named by R&D Magazine as one of the world’s top 100 scientific and technological innovations of that year and recognized with a R&D100 award. Recently we have been developing methods to fabricate networks of ultrasmall (<10nm) Pd nanowires and exploring their sensing capability on H2 gas.