Ag nanoparticles were deposited on the surface of g-C3N4 by a chemical reduction method to increase visible-light absorption via the localized surface plasmon resonance effect, resulting in the reduced recombination of photo-generated electron-holes and enhanced photocatalytic activity. The Ag/g-C3N4 composite with a Ag loading of 3 wt% has the optimum photoactivity that is almost 3.6 and 3.4 times higher than pure g-C3N4 and the same photocatalysis system which has been reported, respectively. Fluorescein was introduced as a photosensitizer and H2 evolution soared to 2014.20 μmol g(-1) h(-1) and the rate is even about 4.8 times higher than that of the 3 wt% Ag/g-C3N4 composite. The chemical structure, composites, morphologies and optical properties of the obtained products are well-characterized by XRD, FTIR, TEM, EDS, XPS and UV-Vis DRS. Meanwhile, the photocatalyst exhibits high stability and reusability.

Owing to the energy crisis and environmental pollution, developing efficient and robust electrochemical energy storage (or conversion) systems is urgently needed but still very challenging. Next-generation electrochemical energy storage and conversion devices, mainly including fuel cells, metal-air batteries, metal-sulfur batteries, and metal-ion batteries, have been viewed as promising candidates for future large-scale energy applications. All these systems are operated through one type of chemical conversion mechanism, which is currently limited by poor reaction kinetics. Single atom catalysts (SACs) perform maximum atom efficiency and well-defined active sites. They have been employed as electrode components to enhance the redox kinetics and adjust the interactions at the reaction interface, boosting device performance. In this Review, we briefly summarize the related background knowledge, motivation and working principle toward nextgeneration electrochemical energy storage (or conversion) devices, including fuel cells, Zn-air batteries, Al-air batteries, Li-air batteries, Li-CO 2 batteries, Li-S batteries, and Na-S batteries. While pointing out the remaining challenges in each system, we clarify the importance of SACs to solve these development bottlenecks. Then, we further explore the working principle and current progress of SACs in various device systems. Finally, future opportunities and perspectives of SACs in next-generation electrochemical energy storage and conversion devices are discussed.

Toxic dyes have threatened human health through the consumption of polluted water, so removal of dyes from wastewater has become a hot topic in both academic and industrial fields. Herein, we reported a kind of cellulose−clay hydrogel with superabsorbent properties, superior mechanical performance, and high dye removal efficiency. The main strategy for the preparation of superabsorbent hydrogels was chemical crosslinking of cellulose, carboxymethyl cellulose (CMC), and the intercalated clay in NaOH/urea aqueous solution. The as-prepared hydrogels exhibited high absorption capacity for methylene blue (MB) solution through a spontaneous physic-sorption process which fitted well with pseudo-second-order and Langmuir isotherm models. The maximum removal efficiencies of hydrogel samples for MB solutions with concentrations of 10 mg L −1 and 100 mg L −1 were 96.6% and 98%, respectively. These results demonstrated that cellulose−clay nanocomposite hydrogels were effective adsorbents for removal of MB dyes, which would provide a new platform for dye decontamination.

TiO 2 /cellulose composite films have been prepared via a sol-gel method from the hydrolysis of a precursor TiO 2 sol solution in the regenerated cellulose films prepared on the basis of cellulose dissolution at low temperature. The structure and properties of the composite films were characterized by using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermal gravimetric analysis, FT-IR, UV-visible spectroscopy, and photocatalytic degradation tests. The micronanoporous structure and hydroxyl groups in the regenerated cellulose films at the wet state provided cavities and affinity for the creation and the immobilization of TiO 2 nanoparticles in the cellulose matrix through electrostatic and hydrogen bonding interactions. The TiO 2 /cellulose composite films exhibited a good photocatalytic activity for photodegradation of phenol under weak UV light irradiation, leading to an important application in photodegradation of organic pollutant. This was a portable photocatalyst, which can be removed out easily from pollutant solution after used, leading to a "green" process.

Focusing on the atomic-scale engineering of CVD grown 2D TMDs, we discuss the six engineering strategies to tailor the electronic structure, conductivity and electrocatalytic properties in detail. Finally, challenges and perspectives are addressed.