Search

The water splitting reaction has the potential to be a sustainable and environmentally friendly way of producing hydrogen as a fuel source, which is an important step in reducing our reliance on fossil fuels and mitigating climate change. Currently, most commonly used catalysts for water splitting are based on precious metals such as platinum and iridium, which are expensive and scarce. Therefore, finding new catalysts that are low-cost, abundant and efficient is of great importance for making water splitting economically viable on a large scale. It was found that pairing up Co nanoparticles (NPs) with MoCx boosted the hydrogen evolution reaction (HER) activity by more than 2-fold (η10 = 130 mV, Tafel slope = 156.08 mV dec−1), compared with the pure Co NPs supported on N-doped carbon (η10 = 337 mV) under alkaline medium conditions. Its activity is comparable to those of Pt single-atom catalysts (SACs) supported on a mesoporous carbon matrix. The good activity may be due to the modification of the D-band of Co by Mo doping and the relatively high electrochemically active surface area (ECSA) of 477.25 cm2, which is comparable to those of Ru SAC materials. [ABSTRACT FROM AUTHOR]

The fashion and textile industry in its current fast-rising business model has generated a huge amount of textile waste during and after the production process. The environmental impact of this waste is well documented as it poses serious threats to lives on earth. To confront the menace of this huge pollution problem, a number of research works were carried out to examine the possible re-utilization of these waste materials without further damaging the environment; for instance, reusing, generating valuable products, or regenerating fibrous materials to form a closed loop in the cotton textile waste lifecycle. This review covers different methodologies to transform cellulosic textile materials into various products with added value, such as cellulosic glucose, cellulase, etc., and finally, to regenerate the fibrous materials for re-application in textiles and fashion. This article presents an overall picture to researchers outlining the possible value addition of textile waste materials. Furthermore, the regeneration of cellulosic fibrous materials from textile waste will be brought into the limelight. [ABSTRACT FROM AUTHOR]

Fast-changing fashion trends have resulted in increases in textile production and waste generation. The environmental impacts of the production, consumption and end-of-life of textiles are amply documented. Therefore, the industry has started to shift from the linear economy principle of 'take-make-waste' to the circular economy concept, where textiles can reenter the life cycle rather than being wasted and thus form a closed loop, resulting in resource savings and reduced environmental impacts. To this end, valorization of solid waste streams from the textile industry to recover fibers and marketable value-added products has gained increasing attention in recent years. Textile waste valorization involves three main steps: pretreatment, enzymatic hydrolysis and fiber regeneration. This review presents the main methodologies and the most recent technical developments in these valorization strategies, the value-added products obtained and their applications. Furthermore, the review describes fermentative products synthesized using cellulosic glucose from the cotton fraction of waste streams. Gaps and challenges in existing strategies are identified for potential future research. This review will help to apprize researchers and practitioners of important recent developments in effective textile valorization via upcycling and guide them in the design of efficient strategies for sustainable management of textile waste streams. [ABSTRACT FROM AUTHOR]

The base-catalyzed rearrangement of secondary vinylphosphines to phosphaalkenes generally affords inseparable mixtures of starting material and product and has therefore proven not to be a viable synthetic route to isolate phosphaalkenes. It is shown that when electron-withdrawing P-subsituents are employed, the rearrangement is quantative making this a useful method to prepare phosphaalkenes with C-alkyl substituents.

The development of low-cost, highly efficient and durable catalysts is the key to the practical use of ammonia borane as a promising storage material for on-board hydrogen production. Atomically dispersed metal supported catalysts not only maximize the efficiency of metal utilization, but they can also act as a robust support for metal nanoparticles. Herein, we report a facile synthesis of a type of carbon nanotube that consists of both Co nanoparticles and atomically dispersed cobalt single-atoms by direct carbonization of a mixture of cobalt-containing precursors and melem-C3N4. Our results suggested that Co nanoparticles were successfully embedded in the layers of graphitic carbon to effectively prevent them from aggregation and loss of catalytic activity. In addition, the Co single atoms greatly lowered the adsorption barriers of water molecules onto the catalysts for fast hydrolysis of ammonia borane. Interestingly, it was found that when the ratio of Co to melem-C3N4 was 1 : 33.3, the best reactivity and stability towards ammonia borane hydrolysis were achieved. The highest specific hydrogen generation rate can reach up to 7833 mLH2 gCo−1 min−1 at 40 °C, which far exceeded most of the non-noble metal catalysts for ammonia borane hydrolysis to date. The durability of the catalyst was successfully maintained for 40 cycling tests and no obvious decay was observed. The current study presents an example of how nanoparticles and single-atoms can be synergistically exploited for heterogeneous catalysis applications. [ABSTRACT FROM AUTHOR]

Sealed-tube reactions or the introduction of an electron-donating group into the carborane cage provided a synthetic pathway to highly chlorinated, brominated and iodinated icosahedral carborane anions. The novel sealed-tube method can compel the halogenation reactions of the parent carborane anion CB(sub 11)H(sub 12)(super -) to proceed to completion while reducing the reaction time and increasing the reaction yield. This new approach can be applied to other carboranes or polyhedral boron clusters.