Direct air capture (DAC) is a process that removes carbon dioxide directly from the atmosphere, independent of emission source. At the heart of every DAC system is a sorbent — a material that selectively binds CO₂ from air at concentrations of around 420 parts per million, then releases it in concentrated form for storage or utilisation. The chemistry and engineering of these sorbents determine the energy cost, scalability, and commercial viability of the entire DAC value chain.

The principal sorbent categories are solid sorbents — including amine-grafted mesoporous silica, metal-organic frameworks (MOFs), and ion-exchange resins — and liquid sorbents such as aqueous potassium hydroxide (KOH) and sodium hydroxide (NaOH) solutions deployed in large-scale systems by companies like Carbon Engineering. Emerging materials such as covalent organic frameworks (COFs) and moisture-swing sorbents, which release CO₂ when exposed to water vapour, represent the next wave of innovation being tracked by PatSnap's IP analytics platform.

The primary technical challenge remains the energy penalty of sorbent regeneration. Releasing captured CO₂ requires significant heat input — particularly for amine-based solid sorbents — and improving CO₂ working capacity, sorbent stability over thousands of adsorption-desorption cycles, and resistance to degradation by moisture and oxygen are the critical R&D priorities for reducing the cost of direct air capture globally. Policy bodies including the International Energy Agency have identified DAC as a key technology for meeting net-zero targets.

The DAC sorbent field is shaped by a small number of fundamental engineering challenges. Understanding which challenges are attracting the most patent activity — and where white space remains — is essential for any R&D team seeking to build a defensible IP position. PatSnap customers in the climate technology space use Eureka to map these dynamics continuously.

Sorbent regeneration energy is the dominant cost driver. For amine-based solid sorbents, temperature-swing adsorption cycles typically require heat at 80–120 °C, while liquid alkaline systems require calcination at over 900 °C. Patent activity around low-temperature regeneration — using waste heat, heat pumps, or electrochemical swing — is growing rapidly as teams seek to break the $100/tonne CO₂ cost barrier. The US Department of Energy has set a target of $100/tonne by 2032 through its Carbon Negative Shot programme.

Sorbent durability is the second major focus. Amine sorbents degrade through oxidation, urea formation, and amine leaching over repeated thermal cycles. Patents protecting stabilised amine formulations, antioxidant additives, and novel support materials with improved hydrothermal stability are among the most commercially valuable in the field. Teams can identify these high-value patent clusters using PatSnap's IP analytics tools. The European Patent Office has seen a marked increase in DAC-related filings since 2020.

Scalable synthesis of advanced sorbents — particularly MOFs and COFs — remains a key barrier. Most MOF synthesis routes demonstrated at laboratory scale are not economically viable at the tonnes-per-year quantities required for commercial DAC. Patent filings in continuous-flow MOF synthesis, spray-drying, and mechanochemical synthesis methods are signalling where the field is moving.