Given the substantial emissions of CO₂ into the atmosphere, there is a critical need for effective CO₂ adsorbents at scale, ideally derived from abundant and sustainable natural resources. In this work, microcrystalline cellulose derived from cotton is used to fabricate cellulose aerogel as porous support via a NaOH/urea-based dissolution and regeneration process, followed by surface modification with a series of amino silane coupling agents to produce aminated cellulose aerogel as CO₂ adsorbent. The as-synthesized optimal adsorbent exhibits a high CO₂ sorption capacity of up to 1.5 and 1.3 mmol g⁻¹ at 0 °C and 25 °C at 1 bar, respectively. Notably, in-depth analysis shows that the adsorbent achieves an impressive capacity of CO₂ uptake of 0.29 mmol g⁻¹ at 25 °C at an exceptionally low CO₂ pressure of 0.4 mbar, i.e., under ambient CO₂ pressure. It implies its potential use as adsorbent both for the traditional point-source capture and the direct air capture as an emerging negative emission technology. This study underscores the environmentally friendly, cost-effective, and biosourced attributes of aminated cellulose aerogel as a compelling alternative for carbon capture, contributing to global initiatives combating CO₂ emissions and stressing the key role of sustainable materials in tackling this global environmental challenge.

Fiber actuators, particularly valuable in soft robotics and environmental sensing, are at the forefront of “smart” materials and materials innovation. In this realm, torsional and tensile biofiber actuators, notable for their cost-effectiveness and biodegradability, mark a critical gap in the development of next-generation functional systems and devices. To address this gap, this study showcased moisture-responsive fiber actuators made from cellulose nanofibrils (CNFs). The initial focus of this contribution was on an innovative torsional actuator, which capitalized on the hydrophilic nature of the CNFs filaments produced through wet-spinning processes. These robust filaments, with a mechanical strength of (237.0 ± 10.7) MPa, were twisted to form the torsional actuator. This actuator demonstrated a rapid rotational response, achieving up to 1180 rpm within merely 10 s of exposure to moisture, and maintained high durability over multiple cycles. Building upon this platform, the study continued and aimed to build up a tensile actuator, which ingeniously integrated a supercoiled nylon fiber core within a moisture-sensitive CNFs sheath. This design enhances the structural support and functionality of the actuator. The pursued transition from torsional to tensile actuator demonstrates an iterative and innovative approach in actuator technology, underscoring the versatility and potential of CNFs in the realm of “smart” actuation materials.

Efficient and long-lasting electrocatalysts are one of the key factors in determining their large-scale commercial viability. Although the fundamentals of deactivation and regeneration of electrocatalysts are crucial for understanding and sustaining durable activity, little has been conducted on metalloids compared to metal-derived ones. Herein, by virtue of in situ seconds-resolved X-ray absorption spectroscopy, we discovered the chemical evolution during the deactivation-regeneration cycles of tellurium clusters supported by nitrogen-doped carbon (termed Te-ACs@NC) as a high-performance electrocatalyst in the hydrogen evolution reaction (HER). Through in situ electrochemical reduction, Te-ACs@NC, which had been deactivated due to surface phase transitions in a previous HER process, was reactivated and regenerated for the next run, where partially oxidized Te was found, surprisingly, to perform better than its nonoxidized state. After 10 consecutive deactivation-regeneration cycles over 480 h, the Te-ACs@NC retained 85% of its initial catalytic activity. Theoretical studies suggest that local oxidation modulates the electronic distribution within individual Te clusters to optimize the adsorption energy of water molecules and reduce dissociation energy. This study provides fundamental insights into the rarely explored metalloid cluster catalysts during deactivation and regeneration and will assist in the future design and development of supported catalysts with high activity and long durability.

Solvent-free ion-conducting elastomers exhibit distinct advantages over hydrogels and ionogels such as zero solvent leakage and high electrochemical stability. However, achieving simultaneous enhancements in both mechanical and ion-conducting properties remains a challenge due to the inherent trade-off in these properties. To overcome this trade-off, we prepared solvent-free ionic elastomers with favorable ionic conductivity and mechanical properties by incorporating MXene into ion-conductive poly(ionic liquid) networks. The elastomers with a suitable MXene content demonstrated a high ionic conductivity of 0.044 S/m at 30 °C and a tensile strength of 0.48 MPa. Structural analysis attributed the enhanced tensile strength to the nanofiller effect of MXene that electrostatically interacts with the poly(ionic liquid) matrix. Dielectric spectroscopy revealed that the addition of MXene facilitates extra pathways for ion transport, thereby improving the ionic conductivity. The solvent-free MXene/poly(ionic liquid) elastomers were utilized as strain sensors and photothermal materials, demonstrating potential applications for personal management and photothermal therapy.

CO₂ sensors are very important; however, their performance is limited by stability and selectivity. This study unveils a capacitive CO₂ sensor with a dielectric layer comprised of amine-functionalized cellulose nanofibril (CNF) foam, significantly enhanced by the addition of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). The core innovation of this research lies in the strategic use of CNF-based foam, which leads to a substantial increase in sensor capacitance, setting a new standard in CO₂ monitoring technologies. The sensor showcases exceptional performance under ambient conditions, with marked improvements in sensitivity towards CO₂. The advancements are attributed to the chemisorption properties of the aminated CNFs combined with the DBU enhancement, facilitating more effective CO₂ capture. By integrating these materials, we present a sensor that opens new avenues for environmental monitoring, healthcare diagnostics, and industrial safety, establishing a new benchmark for capacitive CO₂ sensors in efficiency and environmental sustainability.

Given the abundant solar light available on our planet, it is promising to develop an advanced fabric capable of simultaneously providing personal thermal management and facilitating clean water production in an energy-efficient manner. In this study, we present the fabrication of a photothermally active, biodegradable composite cloth composed of titanium carbide MXene and cellulose, achieved through an electrospinning method. This composite cloth exhibits favorable attributes, including chemical stability, mechanical performance, structural flexibility, and wettability. Notably, our 0.1-mm-thick composite cloth (RC/MXene IV) raises the temperature of simulated skin by 5.6 degrees C when compared to a commercially available cotton cloth, which is five times thicker under identical ambient conditions. Remarkably, the composite cloth (RC/MXene V) demonstrates heightened solar light capture efficiency (87.7%) when in a wet state instead of a dry state. Consequently, this cloth functions exceptionally well as a high-performance steam generator, boasting a superior water evaporation rate of 1.34 kg m(-2) h(-1) under one-sun irradiation (equivalent to 1000 W m(-2)). Moreover, it maintains its performance excellence in solar desalination processes. The multifunctionality of these cloths opens doors to a diverse array of outdoor applications, including solar-driven water evaporation and personal heating, thereby enriching the scope of integrated functionalities for textiles.

Understanding the reconstruction of surface sites is crucial for gaining insights into the true active sites and catalytic mechanisms. While extensive research has been conducted on reconstruction behaviors of atomically dispersed metallic catalytic sites, limited attention has been paid to non-metallic ones despite their potential catalytic activity comparable or even superior to their noble-metal counterpart. Herein, we report a carbonaceous, atomically dispersed non-metallic selenium catalyst that displayed exceptional catalytic activity in the hydrazine oxidation reaction (HzOR) in alkaline media, outperforming the noble-metal Pt catalysts. In situ X-ray absorption spectroscopy (XAS) and Fourier transform infrared spectroscopy revealed that the pristine SeC₄ site pre-adsorbs an ∗OH ligand, followed by HzOR occurring on the other side of the OH–SeC₄. Theoretical calculations proposed that the pre-adsorbed ∗OH group pulls electrons from the Se site, resulting in a more positively charged Se and a higher polarity of Se–C bonds, thereby enhancing surface reactivity toward HzO/R.

Two-dimensional (2D) MXene-based lamellar membranes play transformative roles in membrane filtration technology. Their practical use in water treatment is however hindered by several hurdles, e.g., unfavorable swelling due to weak interactions between adjacent MXene nanosheets, tortuous diffusion pathways of layered stacking, and the intrinsic aquatic oxidation-prone nature of MXene. Herein, nanoporous 2D/2D heterostructure membranes are elaborately constructed via solution-phase assembly of oppositely charged MXene and modified layered double hydroxide (MLDH) nanosheets. As a multifunctional component, positively charged holey MLDH nanosheets were first tailor-made to serve simultaneously as a binder, spacer and surface-modifier; next they were intercalated into negatively charged MXene lamella to enhance structural stability and mass transfer of membranes. As a result, the as-prepared MLDH@MXene heterostructure membranes successfully break the persistent trade-off between high permeability and selectivity while mitigating the common drawbacks in 2D MXene-based lamellar membranes, e.g., swelling issues, restacking problems, and vulnerable chemical stability. Noticeably, at an operating pressure of 4 bar and a feed solution of 100 ppm of Congo red, the heterostructure membranes enable a threefold jump in permeability (332.7 +/- 20 L m(-2) h(-1 )bar(-1)) when compared to the pristine MXene membrane (119.3 +/- 18 L m(-2 )h(-1) bar(-1)), and better operational stability without compromising the rejection.

Controlled synthesis of polymer-based porous membranes via innovative methods is of considerable interest, yet it remains a challenge. Herein, we established a general approach to fabricate porous polyelectrolyte composite membranes (PPCMs) from poly-(ionic liquid) (PIL) and MXene via an ice-assisted method. This process enabled the formation of a uniformly distributed macroporous structure within the membrane. The unique characteristics of the as-produced composite membranes display significant light-to-heat conversion and excellent performance for solar-driven water vapor generation. This facile synthetic strategy breaks new ground for developing composite porous membranes as high-performance solar steam generators for clean water production.

Shortage of clean water continues to grow around the world, and the recent solar-powered interfacial system has emerged as a sustainable, efficient and CO₂-neutral approach to produce clean water. However, complex contaminants in surface water accompanied with environment pollution set huge obstacles for harvesting clean water via previous strategies. Here we develop a solar-powered graphene/alginate hydrogel (GAH)-based clean water extractor of super resistance to the transport of complex contaminants and ultra-antifouling capacity. This GAH features a high selectivity in water transport by rejecting >99.5% of volatile organic compounds, >99.3% of ions (Na⁺, Mg²⁺, K⁺ and Ca²⁺) and 100% of non-volatile organic compounds and bacteria; meanwhile, GAH is capable of rejecting oil adhesion by forming a large contact angle >140° under water, deactivating nearly 100% bacteria on surface and preventing salt crystallization. Given such promising adaptability to a wide environment, this GAH can directly convert surface water of complex components into safe drinkable water.