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"Ji, Jun"
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Manipulating spin polarization of titanium dioxide for efficient photocatalysis
Photocatalysis has been regarded as a promising strategy for hydrogen production and high-value-added chemicals synthesis, in which the activity of photocatalyst depends significantly on their electronic structures, however the effect of electron spin polarization has been rarely considered. Here we report a controllable method to manipulate its electron spin polarization by tuning the concentration of Ti vacancies. The characterizations confirm the emergence of spatial spin polarization among Ti-defected TiO
2
, which promotes the efficiency of charge separation and surface reaction via the parallel alignment of electron spin orientation. Specifically, Ti
0.936
O
2
, possessing intensive spin polarization, performs 20-fold increased photocatalytic hydrogen evolution and 8-fold increased phenol photodegradation rates, compared with stoichiometric TiO
2
. Notably, we further observed the positive effect of external magnetic fields on photocatalytic activity of spin-polarized TiO
2
, attributed to the enhanced electron-spin parallel alignment. This work may create the opportunity for tailoring the spin-dependent electronic structures in metal oxides.
Photocatalyst activity depends significantly on the material’s electronic structures. Here, authors manipulate the electron spin polarization of TiO
2
by tuning the concentration of Ti vacancies and show improved photocatalytic activities.
Journal Article
الأجراس الذهبية
في قرية فاولا وتشوانغ أراد السيد قاو العثور على زوج لابنته الصغرى ولكن الأمر انتهى به الشيطان الخنزير ودعا السيد قاو الكثيرين لإخضاع الشيطان لكنهم فشلوا. وعندما سمع سان تسائخ والقرد أثناء رحلتهما إلى الغرب أن هناك شيطانا في القرية، تطوع الفرد للمساعدة، والتقى بالشيطان الخنزير وحاربه ولحق به إلى كيفه. أدرك الشيطان الخنزير أن سان تسانغ والقرد في رحلة لإحضار الكتب المقدسة، فأخبر القرد أنه كان ينتظرهما بعدما تلقى تعليمات من قوان بن. لكن القرد لم يصدقه فطلب منه أن يحرق كهفه ثم سيأخذه لمقابلة سان تسانغ فك سان تسانغ وثاق الشيطان الخنزير واتخذه تلميذا ثانيا له. واتضح أن الشيطان الخنزير كان قائدا في السماء ولكنه نفي إلى العالم الأرضي لسوء سلوكه، ومنحته قوان بن اسم وو ننغ ثم منحه سان تسانغ اسم \"با جیه\".
Book
Seawater‐Degradable Polymers—Fighting the Marine Plastic Pollution
Polymers shape human life but they also have been identified as pollutants in the oceans due to their long lifetime and low degradability. Recently, various researchers have studied the impact of (micro)plastics on marine life, biodiversity, and potential toxicity. Even if the consequences are still heavily discussed, prevention of unnecessary waste is desired. Especially, newly designed polymers that degrade in seawater are discussed as potential alternatives to commodity polymers in certain applications. Biodegradable polymers that degrade in vivo (used for biomedical applications) or during composting often exhibit too slow degradation rates in seawater. To date, no comprehensive summary for the degradation performance of polymers in seawater has been reported, nor are the studies for seawater‐degradation following uniform standards. This review summarizes concepts, mechanisms, and other factors affecting the degradation process in seawater of several biodegradable polymers or polymer blends. As most of such materials cannot degrade or degrade too slowly, strategies and innovative routes for the preparation of seawater‐degradable polymers with rapid degradation in natural environments are reviewed. It is believed that this selection will help to further understand and drive the development of seawater‐degradable polymers. Plastic pollution of the oceans is a major concern today due to the long life of commodity polymers. The degradation profiles of conventional biodegradable polymers, such as polylactide, polycaprolactone, and others in seawater, are reviewed. As many of them degrade relatively slowly, additional strategies for the development of seawater‐degradable polymers are highlighted.
Journal Article
Advances in Selective Electrochemical Oxidation of 5‐Hydroxymethylfurfural to Produce High‐Value Chemicals
The conversion of biomass is a favorable alternative to the fossil energy route to solve the energy crisis and environmental pollution. As one of the most versatile platform compounds, 5‐hydroxymethylfural (HMF) can be transformed to various value‐added chemicals via electrolysis combining with renewable energy. Here, the recent advances in electrochemical oxidation of HMF, from reaction mechanism to reactor design are reviewed. First, the reaction mechanism and pathway are summarized systematically. Second, the parameters easy to be ignored are emphasized and discussed. Then, the electrocatalysts are reviewed comprehensively for different products and the reactors are introduced. Finally, future efforts on exploring reaction mechanism, electrocatalysts, and reactor are prospected. This review provides a deeper understanding of mechanism for electrochemical oxidation of HMF, the design of electrocatalyst and reactor, which is expected to promote the economical and efficient electrochemical conversion of biomass for industrial applications. This review provides a deeper understanding of mechanism for electrochemical oxidation of 5‐hydroxymethylfurfural (HMF), the design of electrocatalyst and reactor, and points out the possible important development orientation, which is expected to promote the economical and efficient electrochemical conversion of biomass for industrial applications.
Journal Article
Electrocatalysts for Hydrogen Evolution in Alkaline Electrolytes: Mechanisms, Challenges, and Prospective Solutions
Hydrogen evolution reaction (HER) in alkaline medium is currently a point of focus for sustainable development of hydrogen as an alternative clean fuel for various energy systems, but suffers from sluggish reaction kinetics due to additional water dissociation step. So, the state‐of‐the‐art catalysts performing well in acidic media lose considerable catalytic performance in alkaline media. This review summarizes the recent developments to overcome the kinetics issues of alkaline HER, synthesis of materials with modified morphologies, and electronic structures to tune the active sites and their applications as efficient catalysts for HER. It first explains the fundamentals and electrochemistry of HER and then outlines the requirements for an efficient and stable catalyst in alkaline medium. The challenges with alkaline HER and limitation with the electrocatalysts along with prospective solutions are then highlighted. It further describes the synthesis methods of advanced nanostructures based on carbon, noble, and inexpensive metals and their heterogeneous structures. These heterogeneous structures provide some ideal systems for analyzing the role of structure and synergy on alkaline HER catalysis. At the end, it provides the concluding remarks and future perspectives that can be helpful for tuning the catalysts active‐sites with improved electrochemical efficiencies in future. In this review, recent progress and solutions to the challenges associated with electrocatalysts for hydrogen evolution reaction (HER) in alkaline electrolytes are systematically explained. It further describes the reaction controlling factors and ambiguity of the alkaline HER process and outlines the possible ways to enhance the catalyst efficiency and stability. By modifying the electronic structure of catalysts through developing their heterostructures can overcome the water dissociation barrier to realize alkaline HER.
Journal Article
Rational Design of Better Hydrogen Evolution Electrocatalysts for Water Splitting: A Review
The excessive dependence on fossil fuels contributes to the majority of CO2 emissions, influencing on the climate change. One promising alternative to fossil fuels is green hydrogen, which can be produced through water electrolysis from renewable electricity. However, the variety and complexity of hydrogen evolution electrocatalysts currently studied increases the difficulty in the integration of catalytic theory, catalyst design and preparation, and characterization methods. Herein, this review first highlights design principles for hydrogen evolution reaction (HER) electrocatalysts, presenting the thermodynamics, kinetics, and related electronic and structural descriptors for HER. Second, the reasonable design, preparation, mechanistic understanding, and performance enhancement of electrocatalysts are deeply discussed based on intrinsic and extrinsic effects. Third, recent advancements in the electrocatalytic water splitting technology are further discussed briefly. Finally, the challenges and perspectives of the development of highly efficient hydrogen evolution electrocatalysts for water splitting are proposed. This review presents varieties of representative hydrogen evolution reaction (HER) electrocatalysts benefited from intrinsic and extrinsic design strategies and gives insight into classical/novel descriptors and reaction mechanism to provide the audience with a broad and basic understanding. Moreover, the progress on water‐splitting technology is also discussed. Some invigorating perspectives on the challenges and future directions at the HER field are provided.
Journal Article
Cortical structural differences in major depressive disorder correlate with cell type-specific transcriptional signatures
Major depressive disorder (MDD) has been shown to be associated with structural abnormalities in a variety of spatially diverse brain regions. However, the correlation between brain structural changes in MDD and gene expression is unclear. Here, we examine the link between brain-wide gene expression and morphometric changes in individuals with MDD, using neuroimaging data from two independent cohorts and a publicly available transcriptomic dataset. Morphometric similarity network (MSN) analysis shows replicable cortical structural differences in individuals with MDD compared to control subjects. Using human brain gene expression data, we observe that the expression of MDD-associated genes spatially correlates with MSN differences. Analysis of cell type-specific signature genes suggests that microglia and neuronal specific transcriptional changes account for most of the observed correlation with MDD-specific MSN differences. Collectively, our findings link molecular and structural changes relevant for MDD.
The correlation between brain structural changes in major depressive disorder (MDD) and gene expression is unclear. Here, the authors explore the correlation between cell type-specific gene expression changes and cortical structural difference in individuals with major depressive disorder.
Journal Article
A conserved PLPLRT/SD motif of STING mediates the recruitment and activation of TBK1
Nucleic acids from bacteria or viruses induce potent immune responses in infected cells
1
–
4
. The detection of pathogen-derived nucleic acids is a central strategy by which the host senses infection and initiates protective immune responses
5
,
6
. Cyclic GMP-AMP synthase (cGAS) is a double-stranded DNA sensor
7
,
8
. It catalyses the synthesis of cyclic GMP-AMP (cGAMP)
9
–
12
, which stimulates the induction of type I interferons through the STING–TBK1–IRF-3 signalling axis
13
–
15
. STING oligomerizes after binding of cGAMP, leading to the recruitment and activation of the TBK1 kinase
8
,
16
. The IRF-3 transcription factor is then recruited to the signalling complex and activated by TBK1
8
,
17
–
20
. Phosphorylated IRF-3 translocates to the nucleus and initiates the expression of type I interferons
21
. However, the precise mechanisms that govern activation of STING by cGAMP and subsequent activation of TBK1 by STING remain unclear. Here we show that a conserved PLPLRT/SD motif within the C-terminal tail of STING mediates the recruitment and activation of TBK1. Crystal structures of TBK1 bound to STING reveal that the PLPLRT/SD motif binds to the dimer interface of TBK1. Cell-based studies confirm that the direct interaction between TBK1 and STING is essential for induction of IFNβ after cGAMP stimulation. Moreover, we show that full-length STING oligomerizes after it binds cGAMP, and highlight this as an essential step in the activation of STING-mediated signalling. These findings provide a structural basis for the development of STING agonists and antagonists for the treatment of cancer and autoimmune disorders.
A molecular model of STING-mediated signalling is proposed, as structural analysis identifies a crucial motif for the binding of TBK1 to STING, and a separate model involved in IRF-3 binding.
Journal Article