Moisture-swing CO2 capture from air enabled by graphene oxide for agricultural applications

The moisture-swing technique is an effective strategy for directly capturing CO 2 from ambient air. However, adsorption capacity and efficiency of moisture-swing sorbents are limited due to the low specific surface area and lack of porous channels within the materials. Here, we synthesize a graphene oxide sorbent with a specific surface area as high as 107 m 2 g −1 and abundant mesopores within the material. The sorbent delivers a large CO 2 adsorption capacity of 1.354 mmol g −1 under precise control, exceeding most of other similar sorbents. It is mainly attributed to the fast CO 2 diffusion channels (mesopores and surface area) and numerous adsorption sites (oxygen-containing groups) provided by graphene oxide. The sorbent displays excellent working stability with negligible capacity degradation even after 1,000 repeated capture-release cycles. Further, we have demonstrated plant growth promotion of the moisture-swing technique by producing local high CO 2 concentration with our graphene oxide sorbents.