Electrically Conductive Amine-Functionalized Adsorbents Driven by Joule Heating for Direct Air Capture

High energy consumption during regeneration is an important challenge of direct air capture (DAC) technology. Direct Joule heating regeneration is an advanced DAC regeneration technology with a simple system, generating heat inside the material for rapid heating, and supports the use of renewable energy by automated control. We developed a self-conductive amine-functionalized adsorbent that converts renewable electricity into heat, and studied the effects of conductive agent content, amine type, and pore structure. The adsorbent can achieve Joule heating with minimal mass fraction of electrically conductive component, resulting in a high specific capacity and avoiding significant sensible heat consumption, thus leading to low regeneration energy requirements. The Ad-0.48PE/0.32HP/0.20CB adsorbent achieved 2.4 mmol/g CO2 capacity, 120 s desorption time, and 3.5–3.7 GJ/tonne CO2 energy consumption. We built a prototype machine, confirming that the material can achieve rapid regeneration and multiple cycles entirely powered by photovoltaic electricity. Our findings highlight the potential of conductive amine-functionalized adsorbents for DAC technology.