Bidirectionally aligned MXene hybrid aerogels assembled with MXene nanosheets and microgels for supercapacitors

MXene nanomaterials are one of the most promising electrode material candidates for supercapacitors owing to their high conductivity,abundant surface functional groups and large surface area.However,electrodes based on MXene may result in low ion-accessible surface area and blocked ion transport pathways because of the self-restacking of MXene nanosheets.It is essential to suppress the self-res tacking of nanosheets and increase the electrochemical active sites in order to optimize the electrode.In this work,bidirectionally aligned MXene hybrid aerogel(A-MHA)assembled with MXene nanosheets and microgels is prepared using a facile bidirectional freeze casting and freeze-drying method.The bidirectionally aligned structure together with the three-dimensional structured microgels in the A-MHAs,can improve the ionaccessible surface area and provide more barrier-free channels by exposing more active sites and ensuring electrolyte transport freely.The A-MHA with MXene microgels content of 40 wt%exhibits a high specific capacitance of 760 F·g^(-1)at 1 A·g^(-1)and a remarkable cyclic performance of 97%after 10,000 cycles at100 mV·s^(-1)in 1 mol·L^(-1)H_(2)SO_(4)electrolyte.A-MHAs show remarkable electrochemical properties and are of potential application in energy storage.

Oil spill cleanup from sea water by carbon nanotube sponges

Oil spills in the sea have caused many serious environmental problems worldwide. In this study, carbon nanotube （CNT） sponges were used to cleanup oil slicks on sea waters. This method was compared with two traditional representative sorbents, including polypropylene fiber fabric and woolen felt. The CNT sponges had a larger oil sorption capacity than the other two sorbents. The maximum oil sorption capacity （Qm） of the CNT sponge was 92.30 g/g, which was 12 to 13.5 times larger than the Qm of the other two sorbents （the Qm of the polypropylene fiber fabric and woolen felt were 7.45 and 6.74 g/g, respectively）. In addition, unlike the other two sorbents, the CNT sponge was super- hydrophobic and did not adsorb any water during oil spill cleanup. CNT sponges are potentially very useful for cleaning up oil spills from sea water.

Single-material Solvent-sensitive Fluorescent Actuator from Carbon Dots Inverse Opals Based on Gradient Dewetting

A novel solvent-sensitive fluorescent actuator with reversibility has been obtained from carbon dots （CDs） inverse opals, which is prepared via infiltrating CDs solution into the interstice of colloidal crystal template, thermal polymerization of CDs materials and removing the colloidal template. The as-prepared CDs inverse opal actuator shows a bending angle of 75° in 10.2 s, bending rate of 7.35 （°）.s-1. In particular, the fluorescence intensity of the films varies during the actuating process. The actuating behavior is attributed to the inhomogeneous swelling/shrinking of the film, which originates from the gradient dewetting by solvent evaporation and hydrogen-bonding interaction between the solvent molecules and oxygen/hydrogen ions of CDs side chain. The CDs inverse opal actuator has the advantages of quick response, good repeatability and strong fluorescence, which gives an important insight into the design and manufacture of novel and advanced solvent-actuators.