The 'One Belt, One Road' (OBOR) initiatives form the centerpiece of the Chinese leadership's new foreign policy. The OBOR initiatives are a reflection of China's ascendance in the global arena, ...economically, politically, and strategically. Developing inter-connectivity of infrastructure development forms a central part of China's OBOR initiatives. The Asian Infrastructure Investment Bank (AIIB) aims to facilitate and accelerate infrastructure improvement in the region by providing capital loans and technical services. The AIIB will serve as the spearhead of China's OBOR initiatives. The AIIB and OBOR initiatives have put China at the center of geoeconomics and geopolitics in the region and beyond, a position from which it hopes to strengthen its economic ties with other Asian countries. The new Silk Road initiatives also provide a channel for Chinese companies and capital to invest in other countries by leveraging China's strengths in infrastructure development, financial power and manufacturing capacity. The OBOR initiatives and the AIIB could change the economic and political landscape of Asia, the most dynamic and economically vibrant region of the twenty-first century. However, China faces serious challenges, both internally and externally, in implementing these initiatives.
Hydrogen economy has emerged as a very promising alternative to the current hydrocarbon economy, which involves the process of harvesting renewable energy to split water into hydrogen and oxygen and ...then further utilization of clean hydrogen fuel. The production of hydrogen by water electrolysis is an essential prerequisite of the hydrogen economy with zero carbon emission. Among various water electrolysis technologies, alkaline water splitting has been commercialized for more than 100 years, representing the most mature and economic technology. Here, the historic development of water electrolysis is overviewed, and several critical electrochemical parameters are discussed. After that, advanced nonprecious metal electrocatalysts that emerged recently for negotiating the alkaline oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are discussed, including transition metal oxides, (oxy)hydroxides, chalcogenides, phosphides, and nitrides for the OER, as well as transition metal alloys, chalcogenides, phosphides, and carbides for the HER. In this section, particular attention is paid to the catalyst synthesis, activity and stability challenges, performance improvement, and industry‐relevant developments. Some recent works about scaled‐up catalyst synthesis, novel electrode designs, and alkaline seawater electrolysis are also spotlighted. Finally, an outlook on future challenges and opportunities for alkaline water splitting is offered, and potential future directions are speculated.
The hydrogen economy has emerged as a very promising alternative to the current hydrocarbon economy, which involves the process of harvesting renewable energy to split water into hydrogen and oxygen and then further utilization of hydrogen fuel. Alkaline water splitting represents the most mature and economic technology for clean hydrogen production, making high potential for successful implementation of hydrogen economy.
A new kind of nitrogen‐doped graphene/carbon nanotube nanocomposite can be synthesized by a facile hydrothermal process under mild conditions, which exhibits synergistically enhanced electrochemical ...activity for the oxygen reduction reaction. This research provides a new route to access a metal‐free electrocatalyst with high activity under mild conditions.
The anode oxygen evolution reaction (OER) is known to largely limit the efficiency of electrolyzers owing to its sluggish kinetics. While crystalline metal oxides are promising as OER catalysts, ...their amorphous phases also show high activities. Efforts to produce amorphous metal oxides have progressed slowly, and how an amorphous structure benefits the catalytic performances remains elusive. Now the first scalable synthesis of amorphous NiFeMo oxide (up to 515 g in one batch) is presented with homogeneous elemental distribution via a facile supersaturated co‐precipitation method. In contrast to its crystalline counterpart, amorphous NiFeMo oxide undergoes a faster surface self‐reconstruction process during OER, forming a metal oxy(hydroxide) active layer with rich oxygen vacancies, leading to superior OER activity (280 mV overpotential at 10 mA cm−2 in 0.1 m KOH). This opens up the potential of fast, facile, and scale‐up production of amorphous metal oxides for high‐performance OER catalysts.
Amorphous NiFeMo oxide (up to 515 g one batch) with homogeneous elemental distribution was synthesized through a facile supersaturated co‐precipitation method. The amorphous NiFeMo oxide undergoes rapid surface self‐reconstruction during OER that forms a metal oxy(hydroxide) active layer with oxygen vacancies, enabling efficient OER catalysis.
Bimetallic metal–organic frameworks are rationally synthesized as templates and employed for porous carbons with retained morphology, high graphitization degree, hierarchical porosity, high surface ...area, CoNx moiety and uniform N/Co dopant by pyrolysis. The optimized carbon with additional phosphorus dopant exhibits excellent electrocatalytic performance for the oxygen reduction reaction, which is much better than the benchmark Pt/C in alkaline media.
Oil sorbents play a very important part in the remediation processes of oil spills. To enhance the oil‐sorption properties and simplify the oil‐recovery process, various advanced oil sorbents and ...oil‐collecting devices based on them have been proposed recently. Here, we firstly discuss the design considerations for the fabrication of oil sorbents and describe recently developed oil sorbents based on modification strategy. Then, recent advances regarding oil sorbents mainly based on carbon materials and swellable oleophilic polymers are also presented. Subsequently, some additional properties are emphasized, which are required by oil sorbents to cope with oil spills under extreme conditions or to facilitate the oil‐collection processes. Furthermore, some oil‐collection devices based on oil sorbents that have been developed recently are shown. Finally, an outlook and challenges for the next generation of oil‐spill‐remediation technology based on oil‐sorbents materials are given.
Hydrophobic and oleophilic sorbent materials are demonstrated as promising candidates for the cleanup of oil spills. An overview of the latest developments and advances in the fabrication of oil sorbents through modification strategy, carbon‐based oil sorbents, and polymer‐based oil sorbents, as well as some smart oil sorbents and oil‐collecting devices based on oil‐sorbent materials are presented.
We here report that miR‐17‐92 cluster is a novel target for p53‐mediated transcriptional repression under hypoxia. We found the expression levels of miR‐17‐92 cluster were reduced in hypoxia‐treated ...cells containing wild‐type p53, but were unchanged in hypoxia‐treated p53‐deficient cells. The repression of miR‐17‐92 cluster under hypoxia is independent of c‐Myc. Luciferase reporter assays mapped the region responding to p53‐mediated repression to a p53‐binding site in the proximal region of the miR‐17‐92 promoter. Chromatin immunoprecipitation (ChIP), Re‐ChIP and gel retardation assays revealed that the binding sites for p53‐ and the TATA‐binding protein (TBP) overlap within the miR‐17‐92 promoter; these proteins were found to compete for binding. Finally, we show that pri‐miR‐17‐92 expression correlated well with p53 status in colorectal carcinomas. Over‐express miR‐17‐92 cluster markedly inhibits hypoxia‐induced apoptosis, whereas blocked miR‐17‐5p and miR‐20a sensitize the cells to hypoxia‐induced apoptosis. These data indicated that p53‐mediated repression of miR‐17‐92 expression likely has an important function in hypoxia‐induced apoptosis, and thus further our understanding of the tumour suppressive function of p53.
It remains highly desired but a great challenge to achieve atomically dispersed metals in high loadings for efficient catalysis. Now porphyrinic metal–organic frameworks (MOFs) have been synthesized ...based on a novel mixed‐ligand strategy to afford high‐content (1.76 wt %) single‐atom (SA) iron‐implanted N‐doped porous carbon (FeSA‐N‐C) via pyrolysis. Thanks to the single‐atom Fe sites, hierarchical pores, oriented mesochannels and high conductivity, the optimized FeSA‐N‐C exhibits excellent oxygen reduction activity and stability, surpassing almost all non‐noble‐metal catalysts and state‐of‐the‐art Pt/C, in both alkaline and more challenging acidic media. More far‐reaching, this MOF‐based mixed‐ligand strategy opens a novel avenue to the precise fabrication of efficient single‐atom catalysts.
Iron islands: Based on a mixed‐ligand strategy, a porphyrinic MOF was pyrolyzed to afford high‐content single‐atom iron‐implanted N‐doped porous carbon (FeSA‐N‐C). Thanks to the FeSA sites, hierarchical pores, oriented mesochannels, and high conductivity, FeSA‐N‐C exhibits excellent oxygen reduction activity and stability, surpassing almost all non‐noble‐metal catalysts and Pt/C, in both alkaline and the more challenging acidic media.
A high efficiency and great tunability of bandwidth and absorption‐range electromagnetic wave absorber is proposed without precedent. A series of 2D carbon‐based nanocomposites with the loading of ...cerium oxide (CN‐Ce) and other types of rare earth oxides (CN‐REOs) can be successfully synthesized by a simple solvothermal‐sintering method. As‐synthesized 2D nanocomposites with local graphite‐like C3N4 structure and trace N‐doped are identified by transmission electron microscopy, X‐ray photoelectron spectroscopy, X‐ray powder diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. The CN‐REOs and polyvinylidene fluoride composite absorbers with reflection loss values above −40 dB are obtained in C‐band, X‐band, and Ku‐band, respectively. The empirical rules on effective bandwidth and frequency range are discovered and summarized, which can be successfully realized by simply tuning the doping amount or type of REO. The mechanism is explained by enhanced attenuation and tunable impedance matching. In addition co‐filled samples by two types of CN‐REOs nanocomposites are prepared to support these findings and inspire the preparation of absorber with desirable frequency band in the range of 2–18 GHz.
In the system of composites of PVDF and trace n‐doped carbon nanocomposites loaded with rare earth oxide, a high‐performance electromagnetic wave‐absorbing composite with adjustable electromagnetic wave absorption frequency range and adjustable effective absorption width is obtained. Regular performance is found based on extensive experimental data and analysis of intrinsic performance. In addition, the empirical conclusions are well‐validated by co‐filled (CN‐Ce+CN‐Eu)/PVDF samples.
Nitrogen-doped graphene has been a recent research focus. It is crucial to further utilize the excellent properties of graphene macroscopic assemblies. Herein, we first report a unique and convenient ...hydrothermal process for controlled synthesis and structural adjustment of the nitrogen-doped graphene hydrogel (GN-GH), which can be readily scaled-up for mass production of nitrogen-doped graphene hydrogel by using organic amine and graphene oxide as precursors. The organic amine is not only as nitrogen sources to obtain the nitrogen-doped graphene but also as an important modification to control the assembly of graphene sheets in the 3D structures. Inner structure of the GN-GHs and the content of nitrogen in the graphene are easily adjusted by organic amine. Interestingly, it has been found that the supercapacitor performance of the typical product could be remarkably enhanced. Even at an ultrafast charge/discharge rate of 185.0A/g, a high power density of 205.0kW/kg can be obtained. In addition, at a current density of 100.0A/g, 95.2% of its capacitance was retained for 4000 cycles. The present nitrogen-doped graphene hydrogels may have potential applications as ultrahigh power density capacitors in the vehicle, lift and the other devices at high rates.
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► Macroscopic nitrogen-doped graphene hydrogels can be easily synthesized. ► The organic amine acts as nitrogen source and controls the assembly of graphene sheets. ► Inner structure of the nitrogen-doped graphene hydrogels and the content of nitrogen in the graphene can be easily adjusted by organic amine. ► The supercapacitor performance of the nitrogen-doped graphene hydrogels can be remarkably enhanced. ► A high power density of 205.0kW/kg can be reached even at an ultrafast charge/discharge rate of 185.0A/g.
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