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result(s) for
"Han, Chunqiu"
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Modulating electron density of vacancy site by single Au atom for effective CO2 photoreduction
2021
The surface electron density significantly affects the photocatalytic efficiency, especially the photocatalytic CO
2
reduction reaction, which involves multi-electron participation in the conversion process. Herein, we propose a conceptually different mechanism for surface electron density modulation based on the model of Au anchored CdS. We firstly manipulate the direction of electron transfer by regulating the vacancy types of CdS. When electrons accumulate on vacancies instead of single Au atoms, the adsorption types of CO
2
change from physical adsorption to chemical adsorption. More importantly, the surface electron density is manipulated by controlling the size of Au nanostructures. When Au nanoclusters downsize to single Au atoms, the strong hybridization of Au 5
d
and S 2
p
orbits accelerates the photo-electrons transfer onto the surface, resulting in more electrons available for CO
2
reduction. As a result, the product generation rate of Au
SA
/Cd
1−x
S manifests a remarkable at least 113-fold enhancement compared with pristine Cd
1−x
S.
The electron density of reactive sites significantly affects catalytic performances. Here, authors demonstrate the electron density of different reactive sites can be modulated by regulating the type of vacancy and the size of Au, leading to effective CO
2
photoreduction.
Journal Article
Product Peroxidation Inhibition in Methane Photooxidation into Methanol
2024
Methane photooxidation into methanol offers a practical approach for the generation of high‐value chemicals and the efficient storage of solar energy. However, the propensity for C─H bonds in the desired products to cleave more easily than those in methane molecules results in a continuous dehydrogenation process, inevitably leading to methanol peroxidation. Consequently, inhibiting methanol peroxidation is perceived as one of the most formidable challenges in the field of direct conversion of methane to methanol. This review offers a thorough overview of the typical mechanisms involved radical mechanism and active site mechanism and the regulatory methods employed to inhibit product peroxidation in methane photooxidation. Additionally, several perspectives on the future research direction of this crucial field are proposed. This review presents a comprehensive summary of the typical mechanisms employed to inhibit methanol peroxidation, including both the radical mechanism and the active site mechanism, and related various methods for modifying photocatalysts to effectively suppress methanol peroxidation during the methane photooxidation process are summarized. Additionally, several perspectives on the future research direction of this crucial field are proposed.
Journal Article
Spatiotemporal photon distribution control on active sites enables bio-inspired methane-to-methanol conversion
2026
Direct catalytic conversion of methane to methanol offers a pathway for transforming a potent greenhouse gas into a portable clean liquid fuel, thereby mitigating carbon emissions and supporting sustainable energy. However, this process faces challenges from thermodynamically favorable methanol overoxidation. Here, we show that spatiotemporal regulation of photogenerated charge carriers on engineered catalytic sites enables a bio-inspired ordered two-step photocatalytic process that imitates methane monooxygenase. In a platinum-loaded cadmium sulfide photocatalyst, unsaturated sulfur sites modulate hole migration while platinum sites modulate electron migration, ensuring their concurrent surface arrival within picoseconds and prolonged localization. This dynamics temporarily anchors methane at hole-enriched sulfur sites while hydroxyl radical generation occurs at electron-rich platinum sites, decoupling hydroxyl radical formation from methane dehydrogenation to suppress overoxidation. The approach achieves methane-to-methanol conversion with selectivity of 83.5%, offering a bio-inspired solar-driven strategy for C
1
valorization.
Researchers report a bioinspired method to convert methane to methanol via controlled photon distribution on catalyst sites, which achieves 83.5% selectivity, suppressing overoxidation for efficient solar-powered sustainable fuel production.
Journal Article
Keto-enol tautomerism as dynamic electron/hole traps promote charge carrier separation for hydrogen peroxide photosynthesis
2025
Covalent organic frameworks (COFs) are promising photocatalysts for H
2
O
2
photosynthesis, but charge carrier separation remains a critical challenge. Donor-acceptor COFs enhance charge separation, but the slow kinetics of water oxidation and oxygen reduction reactions lead to carrier accumulation, thereby decreasing efficiency. Here, we report T-C type COFs (T = trap units, C = catalytic units), demonstrating that units with keto-enol tautomerism can serve as dynamic electron/hole traps (T) to mitigate Coulomb forces. This design effectively facilitates swift charge transfer and extends carrier lifetimes, thereby enhancing reactions at the C units. Imine COFs derived from 2,4,6-trihydroxybenzaldehyde (Tp) outperform those based on 1,3,5-benzenetricarboxaldehyde due to tautomerization. The optimal Tp COF (TpBpy) achieves an H
2
O
2
generation rate of 37.9 μmol h⁻¹ (or 8350 μmol h⁻¹ g⁻¹) under simulated light, and a solar-to-chemical conversion efficiency of 0.038% in a flow reactor under natural sunlight. This work provides molecular design strategies and standard criteria for efficient H
2
O
2
photocatalysts.
This study shows that keto-enol tautomerism in 2,4,6-trihydroxybenzaldehyde (Tp) imine COFs acts as variable electron/hole traps, boosting exciton dissociation and charge transfer. Tp COF (TpBpy) achieves an photocatalytic H
2
O
2
generation rate of 8350 μmol h
-1
g
-1
under simulated light, and a solar-to-chemical conversion efficiency of 0.038% in a flow reactor under natural sunlight.
Journal Article
Black phosphorus quantum dot/g-C3N4 composites for enhanced CO2 photoreduction to CO
2018
The development of low cost, metal free semiconductor photocatalysts for CO2 reduction to fuels and valuable chemical feedstocks is a practically imperative for reducing anthropogenic CO2 emissions. In this work, black phosphorus quantum dots (BPQDs) were successfully dispersed on a graphitic carbon nitride (g-C3N4) support via a simple electrostatic attraction approach, and the activities of BP@g-C3N4 composites were evaluated for photocatalytic CO2 reduction. The BP@g-C3N4 composites displayed improved carrier separation efficiency and higher activities for photocatalytic CO2 reduction to CO (6.54 μmol g−1 h−1 at the optimum BPQDs loading of 1 wt%) compared with pure g-C3N4 (2.65 μmol g−1 h−1). This work thus identifies a novel approach towards metal free photocatalysts for CO2 photoreduction.
Journal Article
Modulating electron density of vacancy site by single Au atom for effective CO 2 photoreduction
2021
The surface electron density significantly affects the photocatalytic efficiency, especially the photocatalytic CO
reduction reaction, which involves multi-electron participation in the conversion process. Herein, we propose a conceptually different mechanism for surface electron density modulation based on the model of Au anchored CdS. We firstly manipulate the direction of electron transfer by regulating the vacancy types of CdS. When electrons accumulate on vacancies instead of single Au atoms, the adsorption types of CO
change from physical adsorption to chemical adsorption. More importantly, the surface electron density is manipulated by controlling the size of Au nanostructures. When Au nanoclusters downsize to single Au atoms, the strong hybridization of Au 5d and S 2p orbits accelerates the photo-electrons transfer onto the surface, resulting in more electrons available for CO
reduction. As a result, the product generation rate of Au
/Cd
S manifests a remarkable at least 113-fold enhancement compared with pristine Cd
S.
Journal Article
Janus liposozyme for the modulation of redox and immune homeostasis in infected diabetic wounds
2024
Diabetic foot ulcers often become infected, leading to treatment complications and increased risk of loss of limb. Therapeutics to manage infection and simultaneously promote healing are needed. Here we report on the development of a Janus liposozyme that treats infections and promotes wound closure and re-epithelialization. The Janus liposozyme consists of liposome-like selenoenzymes for reactive oxygen species (ROS) scavenging to restore tissue redox and immune homeostasis. The liposozymes are used to encapsulate photosensitizers for photodynamic therapy of infections. We demonstrate application in methicillin-resistant
Staphylococcus aureus
-infected diabetic wounds showing high ROS levels for antibacterial function from the photosensitizer and nanozyme ROS scavenging from the liposozyme to restore redox and immune homeostasis. We demonstrate that the liposozyme can directly regulate macrophage polarization and induce a pro-regenerative response. By employing single-cell RNA sequencing, T cell-deficient
Rag1
−/−
mice and skin-infiltrated immune cell analysis, we further reveal that IL-17-producing γδ T cells are critical for mediating M1/M2 macrophage transition. Manipulating the local immune homeostasis using the liposozyme is shown to be effective for skin wound repair and tissue regeneration in mice and mini pigs.
Therapies for treating bacterial infection and increasing wound healing are needed. Here the authors report a liposozyme that combines reactive oxygen species generation and scavenging for antibacterial action and modulation of redox and immune homeostasis, increasing wound healing.
Journal Article
Huangqi Shengmai Yin Ameliorates Myocardial Fibrosis by Activating Sirtuin3 and Inhibiting TGF-β/Smad Pathway
2021
Myocardial fibrosis (MF) is an important pathological process in which a variety of cardiovascular diseases transform into heart failure. The main manifestation of MF is the excessive deposition of collagen in the myocardium. Here, we explored whether Huangqi Shengmai Yin (HSY) can inhibit isoprenaline (ISO)-induced myocardial collagen deposition in rats, thereby reducing the cardiac dysfunction caused by MF. The results of echocardiography showed that HSY upregulated fractional shortening and ejection fraction, and reduced the left ventricular systolic dysfunction in the rats with MF. Pathological results showed that HSY protected myocardium, inhibited apoptosis, and effectively reduced collagen deposition. HSY also inhibited the expression of collagen I and III and α-smooth muscle actin (α-SMA) in the heart tissue. HSY increased the expression of Sirtuin 3 (Sirt3) and inhibited the protein levels of the components in the transforming growth factor-β (TGF-β)/Smad pathway. At the same time, it also regulated the expression of related proteins in the matrix metalloproteinases family. In summary, HSY played a therapeutic role in rats with ISO-induced MF by protecting myocardium and inhibiting collagen deposition. Therefore, HSY is a potential therapeutic agent for ameliorating MF.
Journal Article
PFC/M1 activation and excitability: a longitudinal cohort study on fatigue symptoms in healthcare workers post-COVID-19
2024
Background
Fatigue is one of the most common neurological symptoms reported post coronavirus disease 2019 (COVID-19) infection. In order to establish effective early intervention strategies, more emphasis should be placed on the correlation between fatigue and cortical neurophysiological changes, especially in healthcare workers, who are at a heightened risk of COVID-19 infection.
Methods
A prospective cohort study was conducted involving 29 COVID-19 medical workers and 24 healthy controls. The assessment included fatigue, sleep and health quality, psychological status, and physical capacity. Functional near-infrared spectroscopy (fNIRS) was employed to detect activation of brain regions. Bilateral primary motor cortex (M1) excitabilities were measured using single- and paired-pulse transcranial magnetic stimulation. Outcomes were assessed at 1, 3, and 6 months into the disease course.
Results
At 1-month post-COVID-19 infection, 37.9% of patients experienced severe fatigue symptoms, dropping to 10.3% at 3 months. Interestingly, the remarkable decreased activation/excitability of bilateral prefrontal lobe (PFC) and M1 were closely linked to fatigue symptoms after COVID-19. Notably, greater increase in M1 region excitability correlated with more significant fatigue improvement. Re-infected patients exhibited lower levels of brain activation and excitability compared to single-infection patients.
Conclusions
Both single infection and reinfection of COVID-19 lead to decreased activation and excitability of the PFC and M1. The degree of excitability improvement in the M1 region correlates with a greater recovery in fatigue. Based on these findings, targeted interventions to enhance and regulate the excitability of M1 may represent a novel strategy for COVID-19 early rehabilitation. Trial registration: The Ethics Review Committee of Xijing Hospital, No. KY20232051-F-1;
www.chictr.org.cn
, ChiCTR2300068444.
Journal Article