Passive radiant cooling is a potentially sustainable thermal management strategy amid escalating global climate change. However, petrochemical-derived cooling materials often face efficiency challenges owing to the absorption of sunlight. We present an intrinsic photoluminescent biomass aerogel, which has a visible light reflectance exceeding 100%, that yields a large cooling effect. We discovered that DNA and gelatin aggregation into an ordered layered aerogel achieves a solar-weighted reflectance of 104.0% in visible light regions through fluorescence and phosphorescence. The cooling effect can reduce ambient temperatures by 16.0°C under high solar irradiance. In addition, the aerogel, efficiently produced at scale through water-welding, displays high reparability, recyclability, and biodegradability, completing an environmentally conscious life cycle. This biomass photoluminescence material is another tool for designing next-generation sustainable cooling materials.

Ultrathin thickness (<1 mm) and ultralow density (<10 mg cm⁻³) are urgent challenges for microwave absorption materials. In this manuscript, we tackle these problems by developing a novel CoNi/reduced graphene oxide (rGO) aerogel absorbent via a facile in situ solvothermal and carbonization process. The resultant CoNi/rGO aerogel with an ultralow density of 7 mg cm⁻³ exhibited a hierarchical porous structure and a high surface area, in which CoNi nanospheres with a diameter of about 50–80 nm were evenly decorated onto the surface of the rGO aerogel matrix. Benefitting from these attributes, the CoNi/rGO aerogel exhibited an excellent microwave absorption performance. The minimum RL value of −53.3 dB was achieved with an ultrathin thickness of 0.8 mm at a low filler loading of 7 wt% in the paraffin template, and the effective absorption bandwidth was >3.5 GHz. The investigation of the absorption mechanism revealed that moderate dielectric loss, magnetic loss, good impedance matching and the porous structure contributed to the high microwave absorption. This work opens up a potential strategy to prepare excellent microwave absorbents with ultrathin thickness and ultralow density.

Recyclable/reversible adhesives have attracted growing attention for sustainability and intelligence but suffer from low adhesion strength and poor durability in complex conditions. Here, we demonstrate an aromatic siloxane adhesive that exploits stimuli-responsive reversible assembly driven by π-π stacking, allowing for elimination and activation of interfacial interactions via infiltration-volatilization of ethanol. The robust cohesive energy from water-insensitive siloxane assembly enables durable strong adhesion (3.5 MPa shear strength on glasses) on diverse surfaces. Long-term adhesion performances are realized in underwater, salt, and acid/alkali solutions (pH 1-14) and at low/high temperatures (−10-90°C). With reversible assembly/disassembly, the adhesive is closed-loop recycled (~100%) and reused over 100 times without adhesion loss. Furthermore, the adhesive has unique combinations of high transparency (~98% in the visible light region of 400-800 nm) and flame retardancy. The experiments and theoretical calculations reveal the corresponding mechanism at the molecular level. This π-π stacking–driven siloxane assembly strategy opens up an avenue for high-performance adhesives with circular life and multifunctional integration.