CACTUS: CO2 Aerogel Capture Towards Utilization and Sequestration

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OPEN 2021
Palo Alto, California
Project Term:
07/01/2022 - 06/30/2025

Critical Need:

Direct air capture (DAC) processes that exclusively use temperature swing adsorption (TSA) to capture carbon dioxide (CO2) have struggled to achieve adoption due to the high overall energy consumption and therefore high operational costs (>$100/tCO2). Moisture swing adsorption (MSA) is a promising alternative strategy that overcomes some TSA limitations using changes in humidity to influence CO2 adsorption on or desorption from a sorbent material. Most sorbents tested for MSA applications thus far have had difficulty in achieving and maintaining the CO2 adsorption capacity, kinetics, and durability necessary to reach competitive economical carbon capture targets (<$100/tCO2, >1 Gt scale, and <5 % embodied emissions). Higher-capacity, higher-throughput sorbents are needed that can maintain good performance for thousands of cycles over multiple years.

Project Innovation + Advantages:

Palo Alto Research Center (PARC) aims to develop a highly efficient sorbent material and MSA process for direct air capture of CO2, leveraging PARC's novel aerogel chemistry incorporating quaternary ammonium cation groups to reversibly adsorb CO2 with changes in humidity. The new material and process will substantially improve the capital and operating costs of CO2 capture through reduced materials and process costs as well as enhanced sorbent performance. The team will advance the critical sorbent materials parameters that drive MSA system performance to give a transformational combination of capacity, sorption/desorption kinetics, cycle life, and cost. The project technology will potentially enable ambient air CO2 capture at the >1 Gt CO2/yr scale at $100/tCO2.

Potential Impact:

PARC will develop a novel, high-performance sorbent for MSA incorporated into a prototype DAC module to de-risk materials integration.


The creation of new sorbent materials and processes for carbon capture will ensure the U.S. maintains a technological lead in developing and deploying advanced carbon capture technologies.


The technology will enable Gt CO2/year DAC at <$100/tCO2 and <5% embodied emissions.


PARC will substantially improve the capital and operating costs of CO2 capture through reduced materials and process costs and enhanced sorbent performance, significantly improving the economic viability of DAC.


ARPA-E Program Director:
Dr. Philseok Kim
Project Contact:
Gabriel Iftime
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