Self-powered sensing potential in CO₂ adsorption-desorption processes

Sensors for detecting the presence, concentration or flow rate of target molecules are widely used in gas detection, environmental monitoring and industrial process control. Given the increasing importance of CO₂ in carbon capture, utilization, storage (CCUS) technologies and various industrial processes, this study explores the micro power generation and sensing potential in CO₂ adsorption-desorption processes. We delve into the micro-mechanisms underlying the temperature response of NaX molecular sieve during these processes. Using Monte Carlo simulations, molecular dynamics simulations and experimental methods, we investigate how the temperature changes during adsorption/desorption processes. Our findings attribute the asymmetric temperature response curve to the molecular sieve's faster adsorption rate of CO₂ compared to its desorption rate under a flashing N₂ flow, leading to a rapid increase in adsorption temperature. Based on the temperature response, we designed a micro power generation device that connects adsorption-induced temperature differentials to measurable electrical signals. The device, based on the temperature difference of up to 84.78 K generated during the adsorption-desorption process, produces a maximum output current of 3.34 mA and a power output of 117.1 μW. This cost-effective, self-powered approach shows great potential for CO₂ sensing and detection of other gases, especially for integration into CCUS and adsorption-desorption-based sensing applications.