Abstract
Real-time monitoring of pollutant, toxic and flammable gases is important for health and safety of petroleum extraction and distribution operations. Small, lightweight, fast, low-power, low-cost sensors would enable ubiquitous monitoring of these gases, which would allow for prevention of exposure or explosions and aid in rapid response to hazardous leaks. Currently, there are many methods of detecting such gases, but most sensors suffer either from slow response times, high power consumption, high cost and/or inability to operate in harsh conditions.
Here we demonstrate a small, low-cost, low-power, highly sensitive and selective nanomaterials-based gas sensor, specifically targeted for the detection of hydrogen sulfide (H2S). A network of WO3 nanoparticles is heated by an on-chip microhotplate while the conductance of the network is monitored. The device can be heated with short pulses (<100 ms) without diminishing the sensor response, thereby drastically lowering the power consumption to less than 1 mW. The sensor shows high sensitivity to H2S, but it does not have direct cross sensitivities to H2O or CH4, two gases likely to be seen in industrial operation.
This low power H2S sensor has been integrated into a low cost, stand-alone monitoring system capable of measuring multiple environmental conditions, including temperature, humidity, and H2S concentration, and distributing that information via wireless protocols, namely 802.15.4 and 802.11 (WiFi). These environmental detection systems can communicate directly to smart phones via WiFi or be configured into a wireless mesh network of detection systems capable of relaying real-time environmental conditions and location to a safety monitor at a remote location. The nanoparticle-based sensor and integrated detection system developed here, once packaged as a fully manufactured tool, can enable a low-cost solution to real-time monitoring of environmental conditions that will greatly reduce the likelihood of hazardous conditions becoming disasters.
