Three-dimensional (3D) conductive aerogels with structural robustness and mechanical resilience are highly attractive for sensitive and stable pressure sensing. However, the fabrication of such 3D aerogels often relies on complicated bottom-up assembly processes that involve costly raw materials or intensive energy consumption or directly coating synthetic polymer sponges (e.g., polyurethane) with conductive materials, which may pose environmental concerns for their disposal. Herein, a simple and sustainable strategy is proposed to fabricate a reduced graphene oxide-coated wood sponge (RGO@WS) with a lamellar structure for high-performance piezoresistive sensors. The introduced RGO nanosheets endow the RGO@WS not only with high conductivity but also with high elasticity and excellent fatigue resistance. These features make it an ideal piezoresistive sensor with a high sensitivity of 0.32 kPa–1 (superior to most polymeric sponge-based sensors), high working stability over 10 000 cycles, and excellent sensing reproducibility at ultralow temperatures. Thanks to its prominent sensing performance, the RGO@WS-based sensor can serve as a wearable device for detecting human motions and physiological signals and allows for spatially resolved pressure mapping via integrating the sensors into a large-area sensing array. The developed highly elastic and fatigue-resistant RGO@WS represents a promising and sustainable alternative to the synthetic polymer-based piezoresistive sensors.

Developing bio-based adsorbents for efficient removal of heavy metal ions from water has attracted increasing attention due to their abundance, low cost, and sustainability. However, most of these adsorbents are in powdered or granular forms, suffering from difficult regeneration and poor recyclability. Here, we report a highly porous three-dimensional amino-functionalized wood aerogel for efficient heavy metal adsorption. The amino-functionalized wood aerogel was prepared from natural balsa wood via a delignification treatment, followed by TEMPO-mediated oxidation of the delignified wood and then grafting polyethylenimine (PEI) onto the oxidized cellulose skeleton. The obtained amino-functionalized wood aerogel possessed a unique porous lamellar structure with a low bulk density of 77.2 mg/cm3 and high porosity of 94.9%. Benefiting from its high porosity and the introduced amino groups on the cellulose skeleton, the amino-functionalized wood aerogel exhibited a maximum Cu(II) adsorption capacity of 59.8 mg·g−1, which was significantly higher than those of the TEMPO-oxidized wood aerogel and natural balsa wood. The adsorption process can be well described by the pseudo-second-order and Langmuir isotherm models, indicating that the Cu(II) adsorption by the PEI@wood aerogel was dominated by a monolayer chemisorption process. The developed amino-functionalized wood aerogel provides new insights for the design of efficient and low-cost monolithic absorbents for heavy metal remediation.

Solar-assisted interfacial evaporation is a promising approach for purifying and desalinating water. As a sustainable biomass material, wood has attracted increasing interest as an innovative substrate for solar desalination, owing to its intrinsic porous structure, high hydrophilicity, and low thermal conductivity. However, developing wood-based solar evaporators with high evaporation rates and excellent salt resistance still remains a significant challenge, owing to the absence of large pores with high interconnectivity in natural wood. Herein, by converting the honeycombed structure of natural wood into a lamellar architecture via structural engineering, we develop a flexible wood sponge with vertically aligned channels for efficient and salt-resistant solar desalination after surface coating with carbon nanotubes (CNTs). The special lamellar structure with an interlayer distance of 50–300 μm provides the wood sponge with faster water transport, lower thermal conductivity, and water evaporation enthalpy, thus achieving higher evaporation performances in comparison with the cellular structure of natural wood. Noteworthy, the vertically aligned channels of the wood sponge facilitate sufficient fluid convection and diffusion and enable efficient salt exchanges between the heating interface and the underlying bulk water, thus preventing salt accumulation on the surface. Benefiting from the distinctive lamellar structure, the developed wood-sponge evaporator exhibits exceptional salt resistance even in a hypersaline brine (20 wt %) during continuous 7-day desalination under 1 sun irradiation, with a high evaporation rate (1.38–1.43 kg m–2 h–1), outperforming most previously reported wood-based evaporators. The lamellar wood sponge may provide a promising strategy for desalinating high-salinity brines in an efficient manner.