The exploration of natural resources as sustainable precursors affords a family of green materials. Exploring highly abundant and available biowaste precursors remaining from food processing throughout a scalable and cost-effective material synthesis path is highly important especially for new materials discovery in emerging energy storage technologies such as lithium–sulphur (Li–S) batteries. Herein, we have produced a series of carbon materials with hierarchical micro-/mesopores from a very cheap and abundant lignocellulosic bio-waste, namely rice husk. The carbonisation of the lignocellulosic fraction leads to the formation of micropores while the removal of the silica present naturally in the rice husk composition allows the formation of mesopores. We can easily tune the ratio of micropores to mesopores by simply tuning the synthesis conditions in order to achieve an optimal performance in Li–S batteries after sulphur infiltration into the resulting porous carbons. Our optimal cathode scaffold for Li–S batteries exhibited a high capacity of 1032 mA h g⁻¹ at a current density of 0.1 C. An ultralow decay rate of 0.055% per cycle was achieved. The appearance of abundant micropores with a higher surface area renders a high initial capacity of sulphur to polysulphides; however, the sufficient mesopore volume is more vital for a lower cyclic decay, which is prerequisite for the generation of solid products and smooth ion diffusion. This work, besides reporting on an efficient method to produce efficient electrode materials from waste to be used in energy storage technologies also provides fresh insights into the required structural features to allow effective cathode materials for high-performance Li–S batteries.

Due to the excellent properties of graphene, including flexibility that allows it to adjust to the curvature of the substrate surface, chemical inertness, and impermeability, graphene is used as an anticorrosion layer. In this review, we present the current state-of-the-art in the application of graphene in the field of protective coatings. This review provides detailed discussions about the protective properties of graphene coatings deposited by different methods, graphene-based organic coatings, the modification of graphene-based coatings, and the effects of graphene functionalization on the corrosion resistance of protective coatings.

Membrane distillation (MD) is a promising technology for seawater desalination due to the ability to process high-salinity waters and the ability to be driven by low-grade or waste heat. However, practical applications of MD membranes are limited by the low vapor flux and fouling problem. Recently, there is a growing interest in developing novel MD membrane materials with enhanced hydrophobicity to improve the efficiency of desalination performance. Interestingly, the incorporation of nanomaterials for tailoring superhydrophobic properties of MD membranes has attracted enormous attention in MD. Herein, according to the new insights of the available literature data, the current trend for achieving superhydrophobic MD membranes by embedding inorganic nanomaterials is provided. The influence of the inorganic additives on membrane fouling, stability, separation performance, is also discussed. Finally, theoretical principles of MD, the milestones of the evolution of developing superhydrophobic membrane surfaces, and future trends are also given for the new readers in the field. Graphical Abstract

By simple thermal decomposition of low-cost precursors (chitosan, melamine) in an inert atmosphere, nitrogen-doped porous carbonaceous materials were prepared. The samples pyrolyzed at 700 °C are composed of mainly mesoporous nitrogen-doped carbon nanosheets and partially graphitized carbon. The nanosheets contain a disordered area due to the strain imposed by the presence of nitrogen and/or oxygen groups in their structure. Some portion of the material is comprised of clean well crystallized graphene sheets. They show an interlayer distance of about 0.359 nm. The average size of the visible well-crystallized carbon is 8 × 8 nm, covering ca. 4% of the samples flat projection. Further, these materials possess total specific areas up to ca. 285 m² g⁻¹, and exhibit efficient electrocatalytic activity (the onset potential of 0.735–0.761 V vs. RHE) for the oxygen reduction reaction (ORR) in alkaline media. Our results show that besides the total nitrogen content and the type of nitrogen group (pyridinic or graphitic), also the amount of carbon ‘kinks’ and/or surface roughness strongly influence the ORR activity.