NiFe-layered double hydroxide (NiFe LDH) is a state-of-the-art oxygen evolution reaction (OER) electrocatalyst, yet it suffers from rather poor catalytic activity for the hydrogen evolution reaction ...(HER) due to its extremely sluggish water dissociation kinetics, severely restricting its application in overall water splitting. Herein, we report a novel strategy to expedite the HER kinetics of NiFe LDH by an Ir4+-doping strategy to accelerate the water dissociation process (Volmer step), and thus this catalyst exhibits superior and robust catalytic activity for finally oriented overall water splitting in 1 M KOH requiring only a low initial voltage of 1.41 V delivering at 20 mA cm−2 for more than 50 h.
This Minireview summarizes the recent progress of stimuli‐responsive purely organic phosphorescence materials. Organic phosphorescence is closely related to the intermolecular interactions, because ...such interactions are beneficial to promote spin orbital coupling (SOC) and boost intersystem cross (ISC) efficiency and finally are conducive to satisfactory phosphorescence. It is found that the intermolecular interactions, which are essential for organic phosphorescence, are easily disturbed by external stimuli such as mechanical force, photon, acid, chemical vapor, leading to the luminescence change. According to this principle, various purely organic phosphorescence materials sensitive to external stimuli have been developed. This Minireview categorizes reported stimuli‐responsive purely organic phosphorescence materials on the basis of different stimuli, including mechanochromism, mechanoluminescence, photoactivity, acid‐responsiveness and other stimuli. Some prospective strategies for constructing stimuli‐responsive purely organic phosphorescence molecules are provided.
Stimulus check: The minireview categorizes reported stimuli‐responsive purely organic phosphorescence materials on the basis of different stimuli, including mechanochromism, mechanoluminescence, photoactivity, acid‐responsiveness and other stimuli. Some prospective strategies for constructing stimuli‐responsive purely organic phosphorescence molecules are provided.
Parkinson's disease is characterized by dopaminergic neuron loss and intracellular inclusions composed mainly of alpha synuclein (α-syn), but the mechanism of pathogenesis is still obscure. In recent ...years, more attention has been given to the gut as a key player in the initiation and progression of PD pathology. Several studies characterizing changes in the microbiome, particularly the gut microbiome, have been conducted. Although many studies found a decrease in the bacterial family Prevotellaceae and in butyrate-producing bacterial genera such as Roseburia and Faecalibacteria, and an increase in the genera Akkermansia many of the studies reported contradictory findings. In this review, we highlight the findings from the different studies and reflect on the future of microbiome studies in PD research.
Doped graphene for metal-free catalysis Kong, Xiang-Kai; Chen, Chang-Le; Chen, Qian-Wang
Chemical Society reviews,
04/2014, Letnik:
43, Številka:
8
Journal Article
Recenzirano
Graphene has attracted increasing attention in different scientific fields including catalysis.
Via
modification with foreign metal-free elements such as nitrogen, its unique electronic and spin ...structure can be changed and these doped graphene sheets have been successfully employed in some catalytic reactions recently, showing them to be promising catalysts for a wide range of reactions. In this review, we summarize the recent advancements of these new and interesting catalysts, with an emphasis on the universal origin of their catalytic mechanisms. We are full of hope for future developments, such as more precisely controlled doping methods, atom-scale surface characterization technology, generating more active catalysts
via
doping, and finding wide applications in many different fields.
This review covers the latest advances in doped graphene for metal-free catalysis.
Electrocatalytic water splitting plays a vital role in the hydrogen fuel industry, but suffers from the lack of efficient non-platinum (Pt) hydrogen evolution reaction (HER) catalysts. Metallic Ru ...has proven to be one of the promising candidates for the HER. However, the syntheses of Ru nanoparticles in previous reports require harsh reaction conditions such as high temperature or very strong external reductants. Herein, we report an extremely simple and mild method to prepare ultra-small Ru nanoparticles
in situ
inlaid into a Ni(OH)
2
nanoarray grown on Ni foam (Ru/Ni(OH)
2
/NF) through the “spontaneous oxidation-reduction reaction” strategy. In 1.0 M KOH, this self-supported material displays a high HER activity with an overpotential as low as 25 mV to deliver a current density of 10 mA cm
−2
, as well as a low Tafel slope of 47 mV dec
−1
. When assembled in a device for overall water splitting, it achieves a current density of 10 mA cm
−2
at 1.50 V and shows outstanding long-term stability even at 50 mA cm
−2
. The present work provides a facile and green strategy to prepare non-Pt HER electrocatalysts and it can be applied to the development of new photo-and electrocatalysts.
A palladium‐catalyzed enantioselective intramolecular σ‐bond cross‐exchange between C−I and C−C bonds is realized, providing chiral indanones bearing an alkyl iodide group and an all‐carbon ...quaternary stereocenter. Pd/TADDOL‐derived phosphoramidite is found to be an efficient catalytic system for both C−C bond cleavage and alkyl iodide reductive elimination. In addition to aryl iodides, aryl bromides can also be used for this transformation in the presence of KI. Density‐functional theory (DFT) calculation studies support the ring‐opening of cyclobutanones occuring through an oxidative addition/reductive elimination process involving PdIV species.
In exchange: An enantioselective cross‐exchange between C−I and C−C bonds is realized by palladium‐catalyzed sequential oxidative addition and reductive elimination. Chiral indanones bearing an alkyl iodide group and an all‐carbon quaternary stereocenter are synthesized in good yields and enantioselectivities.
The development of high-efficiency and low-cost catalysts for hydrogen release from chemical hydrogen-storage materials is essential for the hydrogen-economy paradigm. Herein, we report a facile and ...controllable method to fabricate a series of Co-doped nickel phosphides and their corresponding nanohybrids with graphene oxide (GO) as highly efficient, robust and noble-metal-free catalysts for ammonia borane hydrolysis. The incorporation of Co into Ni
2
P effectively optimizes the electronic structures of Ni
2−x
Co
x
P catalysts to enhance their interaction with AB and simultaneously facilitate the hydroxyl activation of AB, resulting in the reduction of the reaction energy barrier and thus substantial improvement of the catalytic rate.
The environmental instability of single‐ or few‐layer black phosphorus (BP) has become a major hurdle for BP‐based devices. The degradation mechanism remains unclear and finding ways to protect BP ...from degradation is still highly challenging. Based on ab initio electronic structure calculations and molecular dynamics simulations, a three‐step picture on the ambient degradation of BP is provided: generation of superoxide under light, dissociation of the superoxide, and eventual breakdown under the action of water. The well‐matched band gap and band‐edge positions for the redox potential accelerates the degradation of thinner BP. Furthermore, it was found that the formation of P‐O‐P bonds can greatly stabilize the BP framework. A possible protection strategy using a fully oxidized BP layer as the native capping is thus proposed. Such a fully oxidization layer can resist corrosion from water and leave the BP underneath intact with simultaneous high hole mobility.
Protected by native oxide: A three‐step picture of the ambient degradation of black phosphorus (BP) is given. A possible protection strategy using a fully oxidized BP layer as the capping is proposed. Such a fully oxidized layer can resist corrosion from water and leave the BP underneath intact with simultaneous high hole mobility.
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•Denitrifying-anammox sludge was shown to be a promising alternative for the inoculum.•The anammox reactor was successfully started up within 40days.•Evolution of the bacterial ...community was monitored.•Conductivity was used as an indicator to track the start-up process.
Successful start-up of the anaerobic ammonium oxidation (anammox) process in up-flow sludge blanket reactor was achieved by seeding denitrifying (R0) or mixed denitrifying-anammox granular sludge at a 3:1 volume ratio (R1). The results demonstrated that R1 was successfully started-up on day 40 and had a nitrogen removal rate (NRR) of 0.55kgNm−3d−1. By contrast, it took 98days to start up R0 (0.54kgNm−3d−1). R0 and R1 achieved maximum NRRs of 5.70 and 12.02kgNm−3d−1, respectively. The biogranules from R1 generally possessed greater specific anammox activity (SAA), higher extracellular polymeric substance (EPS) and heme c content, larger granules and greater settling velocity. Quantitative PCR (qPCR) and high-throughput sequencing techniques were used to monitor the evolution of the bacterial community. These results demonstrated the feasibility of seeding mixed denitrifying-anammox granular sludge to start-up an anammox reactor.
Hydrogels, a class of materials with a 3D network structure, are widely used in various fields especially in biomedicine. Injectable hydrogels could facilitate the encapsulation and controlled ...release of small molecular drugs, macromolecular therapeutics, and even cells. With the rapid development of cancer immunotherapy, such injectable hydrogels have attracted wide attention for local immunomodulation to boost systemic anticancer immune responses, realizing more effective immunotherapy at lower doses. The latest progresses in the development of various smart injectable hydrogels for cancer immunotherapy are summarized here. Although applied locally, such injectable hydrogels can activate systemic antitumor immune responses, safely and effectively inhibiting the tumor metastasis and recurrence. Moreover, it is discussed how injectable hydrogel‐based cancer immunotherapy would contribute to the development of next generation of cancer treatment together with their potential for clinical translation.
The recently developed injectable smart hydrogels for enhanced cancer immunotherapy are highlighted here. The emerging trends and challenges in this field together with their potential for clinical translation are comprehensively discussed.
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