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1.
Small ; : e2311163, 2024 Feb 02.
Article in English | MEDLINE | ID: mdl-38308114

ABSTRACT

Carbon materials hold significant promise in electrocatalysis, particularly in electrochemical CO2 reduction reaction (eCO2 RR) and two-electron oxygen reduction reaction (2e- ORR). The pivotal factor in achieving exceptional overall catalytic performance in carbon catalysts is the strategic design of specific active sites and nanostructures. This work presents a comprehensive overview of recent developments in carbon electrocatalysts for eCO2 RR and 2e- ORR. The creation of active sites through single/dual heteroatom doping, functional group decoration, topological defect, and micro-nano structuring, along with their synergistic effects, is thoroughly examined. Elaboration on the catalytic mechanisms and structure-activity relationships of these active sites is provided. In addition to directly serving as electrocatalysts, this review explores the role of carbon matrix as a support in finely adjusting the reactivity of single-atom molecular catalysts. Finally, the work addresses the challenges and prospects associated with designing and fabricating carbon electrocatalysts, providing valuable insights into the future trajectory of this dynamic field.

2.
Small ; : e2311132, 2024 Mar 21.
Article in English | MEDLINE | ID: mdl-38511553

ABSTRACT

Metal phthalocyanine molecules with Me-N4 centers have shown promise in electrocatalytic CO2 reduction (eCO2R) for CO generation. However, iron phthalocyanine (FePc) is an exception, exhibiting negligible eCO2R activity due to a higher CO2 to *COOH conversion barrier and stronger *CO binding energy. Here, amine functional groups onto atomic-Fe-rich carbon dots (Af-Fe-CDs) are introduced via a one-step solvothermal molecule fusion approach. Af-Fe-CDs feature well-defined Fe-N4 active sites and an impressive Fe loading (up to 8.5 wt%). The synergistic effect between Fe-N4 active centers and electron-donating amine functional groups in Af-Fe-CDs yielded outstanding CO2-to-CO conversion performance. At industrial-relevant current densities exceeding 400 mA cm-2 in a flow cell, Af-Fe-CDs achieved >92% selectivity, surpassing state-of-the-art CO2-to-CO electrocatalysts. The in situ electrochemical FTIR characterization combined with theoretical calculations elucidated that Fe-N4 integration with amine functional groups in Af-Fe-CDs significantly reduced energy barriers for *COOH intermediate formation and *CO desorption, enhancing eCO2R efficiency. The proposed synergistic effect offers a promising avenue for high-efficiency catalysts with elevated atomic-metal loadings.

3.
Angew Chem Int Ed Engl ; 63(16): e202318589, 2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38385612

ABSTRACT

Catalyst surface dynamics drive the generation of active species for electrocatalytic reactions. Yet, the understanding of dominant site formation and reaction mechanisms is limited. In this study, we thoroughly investigate the dynamic reconstruction of two-dimensional defective Bi nanosheets from exfoliated Bi2Se3 nanosheets under electrochemical CO2 and nitrate (NO3 -) reduction conditions. The ultrathin Bi2Se3 nanosheets obtained by NaBH4-assisted cryo-mediated liquid-phase exfoliation are more easily reduced and reconstructed to Bi nanosheets with high-density grain boundaries (GBs; GB-rich Bi). The reconstructed GB-rich Bi catalyst affords a remarkable yield rate of 4.6 mmol h-1 mgcat. -1 and Faradaic efficiency of 32 % for urea production at -0.40 V vs. RHE. Notably, this yield rate is 2 and 8.2 times higher than those of the low-GB Bi and bulk Bi catalysts, respectively. Theoretical analysis demonstrates that the GB sites significantly reduce the *CO and *NH2 intermediate formation energy and C-N coupling energy barrier, enabling selective urea electrosynthesis on the GB-rich Bi catalyst. This work will trigger further research into the structure-activity interplay in dynamic processes using in situ techniques.

4.
Small ; 19(26): e2302295, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37194952

ABSTRACT

Although the electrocatalytic nitrate reduction reaction (NO3 - RR) is an attractive NH3 synthesis route, it suffers from low yield due to the lack of efficient catalysts. Here, this work reports a novel grain boundary (GB)-rich Sn-Cu catalyst, derived from in situ electroreduction of Sn-doped CuO nanoflower, for effectively electrochemical converting NO3 - to NH3 . The optimized Sn1% -Cu electrode achieves a high NH3 yield rate of 1.98 mmol h-1 cm-2 with an industrial-level current density of -425 mA cm-2 at -0.55 V versus a reversible hydrogen electrode (RHE) and a maximum Faradaic efficiency of 98.2% at -0.51 V versus RHE, outperforming the pure Cu electrode. In situ Raman and attenuated total reflection Fourier transform infrared spectroscopies reveal the reaction pathway of NO3 - RR to NH3 by monitoring the adsorption property of reaction intermediates. Density functional theory calculations clarify that the high-density GB active sites and the competitive hydrogen evolution reaction (HER) suppression induced by Sn doping synergistically promote highly active and selective NH3 synthesis from NO3 - RR. This work paves an avenue for efficient NH3 synthesis over Cu catalyst by in situ reconstruction of GB sites with heteroatom doping.

5.
BMC Public Health ; 23(1): 1486, 2023 08 04.
Article in English | MEDLINE | ID: mdl-37542247

ABSTRACT

BACKGROUND: Little is known about the potential mechanisms of healthy eating and exercise change, and design interventions which aim to promote healthy eating and exercise change among individuals at risk of metabolic syndrome. This study aimed to identify key determinants of healthy eating, exercise behaviors, and health among individuals at risk of metabolic syndrome using the integrated common-sense model of illness self-regulation. METHOD: A cross-sectional study with a multi-wave data collection strategy. A total of 275 participants at risk of metabolic syndrome based on the clinical prediction model were included in the final analysis. Path analysis was employed to explore the pattern of relationships between key variables using AMOS. RESULTS: The mediation analysis suggested that personal and treatment control, and coherence can positively affect self-reported health via intentions and health behaviors (exercise and healthy eating). Additionally, relationships between self-efficacy (exercise and healthy eating) and health outcomes can be mediated by health behaviors, and both intentions and health behaviors. CONCLUSIONS: This current research used the integrated common-sense model of illness self-regulation to predict healthy eating, exercise behaviors, and self-reported health among individuals at risk of metabolic syndrome. The results suggested that self-efficacy, intention, consequences, personal control, treatment control, and coherence were the key determinants of behavior and health, which can help design interventions to encourage healthy eating and exercise changes among individuals with a high risk of MetS.


Subject(s)
Metabolic Syndrome , Self-Control , Humans , Metabolic Syndrome/epidemiology , Feeding Behavior , Diet, Healthy , Cross-Sectional Studies , Models, Statistical , Surveys and Questionnaires , Prognosis , Health Behavior
6.
J Med Internet Res ; 25: e49257, 2023 11 29.
Article in English | MEDLINE | ID: mdl-38019579

ABSTRACT

BACKGROUND: Metabolic syndrome (MetS) is a common public health challenge. Health-promoting behaviors such as diet and physical activity are central to preventing and controlling MetS. However, the adoption of diet and physical activity behaviors has always been challenging. An individualized mobile health (mHealth)-based intervention using the Behavior Change Wheel is promising in promoting health behavior change and reducing atherosclerotic cardiovascular disease (ASCVD) risk. However, the effects of this intervention are not well understood among people with MetS in mainland China. OBJECTIVE: We aimed to evaluate the effects of the individualized mHealth-based intervention using the Behavior Change Wheel on behavior change and ASCVD risk in people with MetS. METHODS: We conducted a quasi-experimental, nonrandomized study. Individuals with MetS were recruited from the health promotion center of a tertiary hospital in Zhejiang province, China. The study involved 138 adults with MetS, comprising a control group of 69 participants and an intervention group of 69 participants. All participants received health education regarding diet and physical activity. The intervention group additionally received a 12-week individualized intervention through a WeChat mini program and a telephone follow-up in the sixth week of the intervention. Primary outcomes included diet, physical activity behaviors, and ASCVD risk. Secondary outcomes included diet self-efficacy, physical activity self-efficacy, knowledge of MetS, quality of life, and the quality and efficiency of health management services. The Mann-Whitney U test and Wilcoxon signed rank test were primarily used for data analysis. Data analysis was conducted based on the intention-to-treat principle using SPSS (version 25.0; IBM Corp). RESULTS: Baseline characteristics did not differ between the 2 groups. Compared with the control group, participants in the intervention group showed statistically significant improvements in diet behavior, physical activity behavior, diet self-efficacy, physical activity self-efficacy, knowledge of MetS, physical health, and mental health after a 12-week intervention (P=.04, P=.001, P=.04, P=.04, P=.001, P=.04, P=.04, and P<.05). The intervention group demonstrated a statistically significant improvement in outcomes from pre- to postintervention evaluations (P<.001, P=.03, P<.001, P=.04, P<.001, P<.001, and P<.001). The intervention also led to enhanced health management services and quality. CONCLUSIONS: The individualized mHealth-based intervention using the Behavior Change Wheel was effective in promoting diet and physical activity behaviors in patients with MetS. Nurses and other health care professionals may incorporate the intervention into their health promotion programs.


Subject(s)
Cardiovascular Diseases , Health Behavior , Metabolic Syndrome , Adult , Humans , Cardiovascular Diseases/prevention & control , Heart Disease Risk Factors , Metabolic Syndrome/therapy , Quality of Life , Risk Factors , Telemedicine , Carotid Artery Diseases/prevention & control
7.
J Clin Nurs ; 32(1-2): 137-146, 2023 Jan.
Article in English | MEDLINE | ID: mdl-35018678

ABSTRACT

AIMS AND OBJECTIVES: To establish a set of scientific and practical nursing care quality evaluation indicators for PACU in China. BACKGROUND: No unified nursing care quality evaluation indicators for post-anaesthesia care unit (PACU) were found in China. DESIGN: An international literature review, domestic cross-sectional survey and two-round e-Delphi study. METHODS: The international literature review and domestic cross-sectional survey were conducted to identify the potential nursing care quality evaluation indicators for PACU. A total of 38 and 32 indicators were extracted from 24 articles and the cross-sectional survey respectively. Two rounds of e-Delphi study were conducted to collect opinions from a panel of 20 independent experts and establish the final version of the nursing care quality evaluation indicators for PACU. A GRRAS checklist was used to guide the reporting of this study. RESULTS: Of 20 experts, 19 completed the first round of e-Delphi study and 18 completed the second round, with a response rate of 95% and 90% respectively. The experts' authority coefficient in the two rounds of e-Delphi study was 0.91 and 0.90 respectively. The Kendall W value of the two rounds ranged between 0.108 and 0.385 (p < .01). Four structure indicators, 12 process indicators and seven outcome indicators were included in the nursing care quality evaluation indicators for PACU. CONCLUSIONS: With the methods of literature review, cross-sectional survey and e-Delphi study, we established a set of scientific and practical nursing care quality evaluation indicators for PACU, to improve the nursing care quality, reduce incidence of complications and ensure patient safety. RELEVANT TO CLINICAL PRACTICE: The findings from this study enable nurses and managers in PACU settings to evaluate clinical nursing care quality using a robust framework.


Subject(s)
Anesthesia , Patient Safety , Humans , Delphi Technique , Cross-Sectional Studies , China , Quality Indicators, Health Care
8.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 52(3): 371-378, 2023 Jun 25.
Article in English, Zh | MEDLINE | ID: mdl-37476948

ABSTRACT

OBJECTIVES: To develop a Chinese version of the Long-Term Conditions Questionnaire (LTCQ) and to test its reliability and validity in Chinese patients with chronic diseases. METHODS: With the consent of the original authors, a Chinese version of LTCQ was developed according to the cultural adjustment guidelines. A questionnaire survey was conducted on 319 patients with chronic diseases in Sir Run Run Shaw Hospital, Wuyi County First People's Hospital and Hangzhou Gongchen Bridge Street Health Service Center. The questionnaire was evaluated by item analysis (including frequency analysis, total question correlation method and critical ratio method), reliability analysis (Cronbach's alpha coefficient) and validity analysis [including content validity (expert scoring method) and structural validity (exploratory factor analysis)]. RESULTS: The Chinese version of the LTCQ included 20 entries, with a Cronbach's alpha coefficient of 0.926, a retest reliability of 0.829, a split-half reliability of 0.878, an entry content validity index of 1, and a content validity index at the questionnaire level of 1. Four common factors were extracted by exploratory factor analysis, namely physical state and daily life, psychological state, support and coping, and safe environment, with a cumulative variance contribution rate of 67.244%. Discussion: The Chinese version of the LTCQ developed in this study has good reliability and validity and it may be used to assess the long-term conditions of patients with chronic diseases in China.


Subject(s)
Asian People , Quality of Life , Humans , China , Chronic Disease , Reproducibility of Results , Surveys and Questionnaires
9.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 52(3): 361-370, 2023 Jun 25.
Article in English, Zh | MEDLINE | ID: mdl-37476947

ABSTRACT

OBJECTIVES: To develop a Chinese version of the Stress Adaption Scale (SAS) and to assess its reliability and validity among Chinese patients with multimorbidity. METHODS: The Brislin model was used to translate, synthesize, back-translate, and cross culturally adapt the SAS. A total of 323 multimorbidity patients selected by convenience sampling method from four hospitals in Zhejiang province. The critical ratio method, total question correlation method, and graded response model (item characteristic curve and item discrimination) were used for item analysis. Cronbach's alpha coefficient and split-half reliability were used for the reliability analysis. Content validity analysis, structural validity analysis, and criterion association validity analysis were performed by expert scoring method, confirmatory factor analysis, and Pearson correlation coefficient method, respectively. RESULTS: The Chinese version of the SAS contained 2 dimensions of resilience and thriving, with a total of 10 items. In the item analysis, the critical ratio method showed that the critical ratio of all items was greater than 3.0 (P<0.001); the correlation coefficient method showed that the Pearson correlation coefficients for all items exceeded 0.4 (P<0.01). The graded response model showed that items of the revised scale exhibited distinct item characteristic curves and all items had discrimination parameters exceeding 1.0. In the reliability analysis, Cronbach's alpha coefficient of the revised Chinese version of the SAS scale was 0.849, and the split-half reliability was 0.873. In the validity analysis, the item-level content validity index and scale-level content validity index both exceeded 0.80. In the confirmatory factor analysis, the revised two-factor model showed satisfactory fit indices (χ2/df=3.115, RMSEA=0.081, RMR=0.046, GFI=0.937, AGFI=0.898, CFI=0.936, TLI=0.915). In the criterion-related validity analysis, the Chinese version of the SAS score was negatively correlated with the Perceived Stress Scale and the Treatment Burden Questionnaire, with correlation coefficients of -0.592 and -0.482, respectively (both P<0.01). CONCLUSIONS: The Chinese version of the SAS has good reliability and validity, which can be used to evaluate the stress adaption capacity among multimorbidity patients in China, and provides a reference for developing individualized health management measures.


Subject(s)
Adaptation, Psychological , Asian People , Multimorbidity , Stress, Psychological , Humans , China , Reproducibility of Results , Stress, Psychological/ethnology , Stress, Psychological/psychology , Surveys and Questionnaires , Translating , Cross-Cultural Comparison
10.
BMC Public Health ; 22(1): 1740, 2022 09 14.
Article in English | MEDLINE | ID: mdl-36104817

ABSTRACT

BACKGROUND: Adherence to physical activity is inadequate in adults with metabolic syndrome. Adherence to physical activity recommendations is crucial and can result in improved health outcomes and reduced medical burdens. A comprehensive behavior change intervention, including identifying determinants of adherence to physical activity recommendations, intervention options, intervention content and implementation options, was imperative for enhancing physical activity adherence. The aim of the study is to develop an intervention to increase physical activity adherence among individuals with metabolic syndrome. METHODS: The study followed the eight steps of the Behavior Change Wheel guide, including defining the problem in behavioral terms (Step 1), selecting target behavior (Step 2), specifying target behavior (Step 3), identifying what needs to change (Step 4), identifying intervention functions (Step 5), identifying policy categories (Step 6), identifying behavior change techniques (Step 7), and determining model of delivery (Step 8). The semi-structured, in-depth interviews were employed to identify the determinants of adherence to physical activity among twenty-eight individuals with metabolic syndrome based on capability, opportunity, motivation and behavior model. Next, the intervention functions and policy categories were chosen to address these determinants. Finally, behavior change techniques were selected to assist in the delivery of the intervention functions and be translated into intervention content. RESULTS: Our study identified eighteen facilitators and fifteen barriers to physical activity adherence. It resulted in the selection of seven intervention functions and nineteen behavior change techniques for the intervention program. Then, the current study identified an app as the delivery mode. Finally, a behavioral change intervention was generated for individuals with metabolic syndrome to increase physical activity recommendation adherence. CONCLUSIONS: The Behavior Change Wheel provided a systematic approach to designing a behavior change intervention, which helped improve the health outcomes and reduce medical burdens and economic burdens among individuals with metabolic syndrome. The findings suggested that potential intervention should pay special attention to increasing knowledge in metabolic syndrome, imparting skills of physical activity, offering a supportive environment, and providing suggestions on regular physical activity using the appropriate behavior change techniques. A feasibility study will be undertaken to assess the acceptability and effectiveness of the intervention program in the future.


Subject(s)
Metabolic Syndrome , Adult , Behavior Therapy/methods , Exercise , Feasibility Studies , Humans , Metabolic Syndrome/therapy , Motivation
11.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 51(1): 115-121, 2022 Feb 25.
Article in English | MEDLINE | ID: mdl-35576113

ABSTRACT

: To design and develop a Wechat applet for intelligent health management of metabolic syndrome. Based on the needs and requirements of individuals undergoing health check-up, patients with metabolic syndrome and medical workers, a Wechat applet for metabolic syndrome management was designed and developed, which involving health data collection, health risk prediction, health management knowledge base fusion and intelligent recommendation, data privacy and security. The platform consists of three user ports: individuals undergoing health check and patients with metabolic syndrome, the medical workers and the system administrators. The main functions of the platform included metabolic syndrome risk prediction, intelligent recommendation of health management strategies, health behavior record and supervision, experts' consultation and health knowledge guide. The Wechat applet developed in this study can be used for metabolic syndrome risk prediction for general population, and health management for patients with metabolic syndrome, which helps them to enhance health management awareness and health behavior adherence.


Subject(s)
Metabolic Syndrome , Humans , Metabolic Syndrome/therapy , Software
12.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 51(1): 27-37, 2022 Feb 25.
Article in English | MEDLINE | ID: mdl-35576114

ABSTRACT

To evaluate and summarize the evidence of diet and physical activity management in patients with metabolic syndrome (MS). BMJ Best Practice, UpToDate, Joanna Briggs Institute (JBI) database, Agency for Healthcare Research and Quality (AHRQ) network, National Institute for Health and Clinical Excellence (NICE) network, Scottish Intercollegiate Guidelines Network (SIGN), Guidelines International Network (GIN), Medlive, Registered Nurses' Association of Ontario (RNAO) network, American Diabetes Association (ADA) network, New Zealand Guideline Group (NZGG) network, Canadian medical association clinical practice guidelines network, PubMed, EmBase, Web of Science, CINAHL, Cochrane Library, CNKI, China Science and Technology Journal Database, Wanfang Knowledge Data Service Platform and Chinese biomedical database were searched systematically to obtain guidelines, evidence summary, expert consensus, best practice information book, clinical decision-making, recommended practice, and systematic review on diet and physical activity management in patients with MS. The retrieval period is from the establishment of database to November 2021. Two researchers with evidence-based medicine background evaluated the quality and evidence level of the included literature. A total of 36 articles met the criteria, including 3 guidelines, 5 expert consensus, 1 clinical decision and 27 systematic reviews. We summarized 49 pieces of evidence related to diet and physical activity in patients with MS, involving 15 aspects, namely diet goals, diet patterns, diet time, carbohydrate intake, fat intake, fiber intake, salt intake, fruits, vegetables and grains intake, coffee intake, effects of diet, principle of physical activity, intensity, form, time of physical activity, effects of physical activity, physical activity prescription of patients with MS and cardiovascular disease, and the joint effects of diet and physical activity. Diet and physical activity management can effectively improve the health outcomes of patients with MS. Health professionals should choose and apply the best evidence with consideration of the clinical situation and patient preference.


Subject(s)
Metabolic Syndrome , Canada , Consensus , Diet , Exercise , Humans , Metabolic Syndrome/therapy
13.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 51(1): 19-26, 2022 Feb 25.
Article in English | MEDLINE | ID: mdl-35576110

ABSTRACT

: To explore the potential associations between perceived stress and health-promoting behaviors based on the theoretical schema of the middle-range theory of adaptation to chronic illness. From January to May 2021, a convenience sampling method was used to recruit 230 young and middle-aged patients with metabolic syndrome who underwent physical examination in the inpatient center of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine. The Health-Promoting Health Profile-Ⅱ, Chinese Perceived Stress Scale, Coping and Adaptation Processing Scale-Short Form, and Multi-dimensional Scale of Perceived Social Support were used in the cross-sectional study. The chain mediation effect procedure and bootstrap sampling test were used to examine the mediating role of adaptability and social support between perceived stress and health-promoting behaviors. The mean score of health-promoting behaviors was 100.0±14.6, the mean score of perceived stress was 22.0± 6.9, the mean score of adaptability was 47.0±6.1, and the mean score of social support was 63.8±10.8. Perceived stress had a negative impact on patients' health-promoting behaviors (=-0.309, <0.05). The adaptability (effect size= -0.112, 95%:-0.199~-0.038) and social support (effect size= -0.032, 95%:-0.083~played a mediating role and a chain mediating role in the process of perceived stress influencing patients' health-promoting behaviors (effect size= -0.045, 95%:-0.093~-0.020). Adaptability and social support play an intermediary role between perceived stress and health-promoting behaviors in young and middle-aged patients with metabolic syndrome. Healthcare professionals can motivate patients to develop healthy behaviors by developing intervention strategies on adaptability and social support.


Subject(s)
Metabolic Syndrome , Adaptation, Psychological , Cross-Sectional Studies , Humans , Middle Aged , Social Support , Stress, Psychological
14.
Small ; 16(22): e1906782, 2020 06.
Article in English | MEDLINE | ID: mdl-32363806

ABSTRACT

Single atom catalysts (SACs) are widely researched in various chemical transformations due to the high atomic utilization and catalytic activity. Carbon-supported SACs are the largest class because of the many excellent properties of carbon derivatives. The single metal atoms are usually immobilized by doped N atoms and in some cases by C geometrical defects on carbon materials. To explore the catalytic mechanisms and improve the catalytic performance, many efforts have been devoted to modulating the electronic structure of metal single atomic sites. Doping with polynary metals and heteroatoms has been recently proposed to be a simple and effective strategy, derived from the modulating mechanisms of metal alloy structure for metal catalysts and from the donating/withdrawing heteroatom doping for carbon supports, respectively. Polynary metals SACs involve two types of metal with atomical dispersion. The bimetal atom pairs act as dual catalytic sites leading to higher catalytic activity and selectivity. Polynary heteroatoms generally have two types of heteroatoms in which N always couples with another heteroatom, including B, S, P, etc. In this Review, the recent progress of polynary metals and heteroatoms SACs is summarized. Finally, the barriers to tune the activity/selectivity of SACs are discussed and further perspectives presented.

15.
Small ; 15(11): e1804613, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30730101

ABSTRACT

Although photocatalysis is one of the most promising technologies for environmental and energy issues, the irreconcilable contradiction between the absorption of the visible light and the strong redox capability of the photocatalyst and the low photocatalytic reaction kinetics result in the poor efficiency. Here, a composite photocatalyst is reported with high redox capability and accelerated reaction kinetics synergistically utilizing 2D semiconducting structural advantages and the noble-metal-free Schottky junction effect. The 2D structure can not only increase the bandgap of the photocatalyst but also improve the transfer and separation of the photogenerated charge carriers. Furthermore, the introduction of the noble-metal-free Schottky junction effect accelerates the photocatalytic reaction kinetics. The Schottky barrier can also prevent the photogenerated charges trapped by the electron acceptor from flowing back to the semiconductor, which can further boost the photocatalytic performance. The transfer process of the photogenerated charge carriers is also researched in detail by the comprehensive characterization methods, which enable the photocatalytic mechanism to be revealed.

16.
Nano Lett ; 16(1): 466-70, 2016 Jan 13.
Article in English | MEDLINE | ID: mdl-26651056

ABSTRACT

The practical recycling of carbon dioxide (CO2) by the electrochemical reduction route requires an active, stable, and affordable catalyst system. Although noble metals such as gold and silver have been demonstrated to reduce CO2 into carbon monoxide (CO) efficiently, they suffer from poor durability and scarcity. Here we report three-dimensional (3D) graphene foam incorporated with nitrogen defects as a metal-free catalyst for CO2 reduction. The nitrogen-doped 3D graphene foam requires negligible onset overpotential (-0.19 V) for CO formation, and it exhibits superior activity over Au and Ag, achieving similar maximum Faradaic efficiency for CO production (∼85%) at a lower overpotential (-0.47 V) and better stability for at least 5 h. The dependence of catalytic activity on N-defect structures is unraveled by systematic experimental investigations. Indeed, the density functional theory calculations confirm pyridinic N as the most active site for CO2 reduction, consistent with experimental results.

17.
Small ; 12(20): 2741-9, 2016 May.
Article in English | MEDLINE | ID: mdl-27059403

ABSTRACT

A proper design of direct liquid phase exfoliation (LPE) for 2D materials as graphene, MoS2 , WS2 , h-BN, Bi2 Se3 , MoSe2 , SnS2 , and TaS2 with common cosolvents is carried out based on considering the polar and dispersive components of surface tensions of various cosolvents and 2D materials. It has been found that the exfoliation efficiency is enhanced by matching the ratio of surface tension components of cosolvents to that of the targeted 2D materials, based on which common cosolvents composed of IPA/water, THF/water, and acetone/water can be designed for sufficient LPE process. In this context, the library of low-toxic and low-cost solvents with low boiling points for LPE is infinitely enlarged when extending to common cosolvents. Polymer-based composites reinforced with a series of different 2D materials are compared with each other. It is demonstrated that the incorporation of cosolvents-exfoliated 2D materials can substantially improve the mechanical and thermal properties of polymer matrices. Typically, with the addition of 0.5 wt% of such 2D material as MoS2 nanosheets, the tensile strength and Young's modulus increased up to 74.85% and 136.97%, respectively. The different enhancement effect of 2D materials is corresponded to the intrinsic properties and LPE capacity of 2D materials.

18.
Nano Lett ; 15(8): 5449-54, 2015 Aug 12.
Article in English | MEDLINE | ID: mdl-26200657

ABSTRACT

Exfoliation of two-dimensional (2D) materials into mono- or few layers is of significance for both fundamental studies and potential applications. In this report, for the first time surface tension components were directly probed and matched to predict solvents with effective liquid phase exfoliation (LPE) capability for 2D materials such as graphene, h-BN, WS2, MoS2, MoSe2, Bi2Se3, TaS2, and SnS2. Exfoliation efficiency is enhanced when the ratios of the surface tension components of the applied solvent is close to that of the 2D material in question. We enlarged the library of low-toxic and common solvents for LPE. Our study provides distinctive insight into LPE and has pioneered a rational strategy for LPE of 2D materials with high yield.

19.
Angew Chem Int Ed Engl ; 54(46): 13701-5, 2015 Nov 09.
Article in English | MEDLINE | ID: mdl-26404732

ABSTRACT

Nitrogen-doped carbon nanotubes (NCNTs) have been considered as a promising electrocatalyst for carbon-dioxide-reduction reactions, but two fundamental chemistry questions remain obscure: 1) What are the active centers with respect to various defect species and 2) what is the role of defect density on the selectivity of NCNTs? The aim of this work is to address these questions. The catalytic activity of NCNTs depends on the structural nature of nitrogen in CNTs and defect density. Comparing with pristine CNTs, the presence of graphitic and pyridinic nitrogen significantly decreases the overpotential (ca. -0.18 V) and increases the selectivity (ca. 80%) towards the formation of CO. The experimental results are in congruent with DFT calculations, which show that pyridinic defects retain a lone pair of electrons that are capable of binding CO2. However, for graphitic-like nitrogen, electrons are located in the π* antibonding orbital, making them less accessible for CO2 binding.

20.
iScience ; 27(6): 110005, 2024 Jun 21.
Article in English | MEDLINE | ID: mdl-38846002

ABSTRACT

Electrocatalysts undergo structural evolution under operating electrochemical CO2 reduction reaction (CO2RR) conditions. This dynamic reconstruction correlates with variations in CO2RR activity, selectivity, and stability, posing challenges in catalyst design for electrochemical CO2RR. Despite increased research on the reconstruction behavior of CO2RR electrocatalysts, a comprehensive understanding of their dynamic structural evolution under reaction conditions is lacking. This review summarizes recent developments in the dynamic reconstruction of catalysts during the CO2RR process, covering fundamental principles, modulation strategies, and in situ/operando characterizations. It aims to enhance understanding of electrocatalyst dynamic reconstruction, offering guidelines for the rational design of CO2RR electrocatalysts.

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