Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 6 de 6
Filter
Add more filters










Database
Language
Publication year range
1.
Small ; : e2400783, 2024 Apr 04.
Article in English | MEDLINE | ID: mdl-38573959

ABSTRACT

Endowing conventional materials with specific functions that are hardly available is invariably of significant importance but greatly challenging. TiO2 is proven to be highly active for the photocatalytic hydrogen evolution while intrinsically inert for electrocatalytic hydrogen evolution reaction (HER) due to its poor electrical conductivity and unfavorable hydrogen adsorption/desorption behavior. Herein, the first activation of inert TiO2 for electrocatalytic HER is demonstrated by synergistically modulating the positions of d-band center and triggering hydrogen spillover through the dual doping-induced partial phase transition. The N, F co-doping-induced partial phase transition from anatase to rutile phase in TiO2 (AR-TiO2|(N,F)) exhibits extraordinary HER performance with overpotentials of 74, 80, and 142 mV at a current density of 10 mA cm-2 in 1.0 M KOH, 0.5 M H2SO4, and 1.0 M phosphate-buffered saline electrolytes, respectively, which are substantially better than pure TiO2, and even superior to the benchmark Pt/C catalysts. These findings may open a new avenue for the development of low-cost alternative to noble metal catalysts for electrocatalytic hydrogen production.

2.
Adv Mater ; 35(42): e2210975, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37200014

ABSTRACT

Atomically dispersed transition metal-nitrogen/carbon (M-N/C) catalysts have emerged as the most promising substitutes to the precious platinum counterparts toward the oxygen reduction reaction (ORR). However, the reported M-N/C catalysts are usually in the form of common M-N4 moieties with only a single metal active site, and they suffer from insufficient activity. Herein, an unusual trinuclear active structure is elaborately developed with a nitrogen-coordinated single Mn atom adjacent to two Co atoms (Co2 MnN8 ) anchored in N-doped carbon as a highly efficient ORR catalyst via adsorption-pyrolysis of a bimetallic zeolitic imidazolate framework precursor. Atomic structural investigations and density functional theory (DFT) calculations reveal that Co2 MnN8 would experience a spontaneous OH binding to form Co2 MnN8 -2OH as the real active site, leading to a single electron-filled state in the d z 2 ${\mathrm{d}}_{{z}^{2}}$ orbital and an optimized binding energy of intermediates. Accordingly, the as-developed Co2 MnN8 /C exhibits an unprecedented ORR activity with a high half-wave potential of 0.912 V and outstanding stability, not only surpassing the Pt/C catalyst but also representing a new record for the Co-based catalyst.

3.
Adv Mater ; 34(17): e2109605, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35233852

ABSTRACT

Engineering non-precious transition metal (TM)-based electrocatalysts to simultaneously achieve an optimal intrinsic activity, high density of active sites, and rapid mass transfer ability for the oxygen reduction reaction (ORR) remains a significant challenge. To address this challenge, a hybrid composite consisting of Fex Co alloy nanoparticles uniformly implanted into hierarchically ordered macro-/meso-/microporous N-doped carbon polyhedra (HOMNCP) is rationally designed. The combined results of experimental and theoretical investigations indicate that the alloying of Co enables a favorable electronic structure for the formation of the *OH intermediate, while the periodically trimodal-porous structured carbon matrix structure not only provides highly accessible channels for active site utilization but also dramatically facilitates mass transfer in the catalytic process. As expected, the Fe0.5 Co@HOMNCP composite catalyst exhibits extraordinary ORR activity with a half-wave potential of 0.903 V (vs reversible hydrogen electrode), surpassing most Co-based catalysts reported to date. More remarkably, the use of the Fe0.5 Co@HOMNCP catalyst as the air electrode in a zinc-air battery results in superior open-circuit voltage and power density compared to a commercial Pt/C + IrO2 catalyst. The results of this study are expected to inspire the development of advanced TM-based catalysts for energy storage and conversion applications.

4.
Adv Mater ; 34(20): e2107548, 2022 May.
Article in English | MEDLINE | ID: mdl-35306709

ABSTRACT

Developing an efficient and non-precious pH-universal hydrogen evolution reaction electrocatalyst is highly desirable for hydrogen production by electrochemical water splitting but remains a significant challenge. Herein, a hierarchical structure composed of heterostructured Ni2 P-Ni12 P5 nanorod arrays rooted on Ni3 S2 film (Ni2 P-Ni12 P5 @Ni3 S2 ) via a simultaneous corrosion and sulfidation is built followed by a phosphidation treatment toward the metallic nickel foam. The combination of theoretical calculations with in/ex situ characterizations unveils that such a unique sequential phase conversion strategy ensures the strong interfacial coupling between Ni2 P and Ni12 P5 as well as the robust stabilization of 1D heteronanorod arrays by Ni3 S2 film, resulting in the promoted water adsorption/dissociation energy, the optimized hydrogen adsorption energy, and the enhanced electron/proton transfer ability accompanied with an excellent stability. Consequently, Ni2 P-Ni12 P5 @Ni3 S2 /NF requires only 32, 46, and 34 mV overpotentials to drive 10 mA cm-2 in 1.0 m KOH, 0.5 m H2 SO4 , and 1.0 m phosphate-buffered saline electrolytes, respectively, exceeding almost all the previously reported non-noble metal-based electrocatalysts. This work may pave a new avenue for the rational design of non-precious electrocatalysts toward pH-universal hydrogen evolution catalysis.

5.
Front Hum Neurosci ; 14: 576114, 2020.
Article in English | MEDLINE | ID: mdl-33262696

ABSTRACT

Numerous studies find that creativity is not only associated with low effort and flexible processes but also associated with high effort and persistent processes especially when defensive behavior is induced by negative emotions. The important role of self-esteem is to buffer negative emotions, and individuals with low self-esteem are prone to instigating various forms of defensive behaviors. Thus, we thought that the relationships between trait creativity and executive control brain networks might be modulated by self-esteem. The resting-state electroencephalogram (RS-EEG) microstates can be divided into four classical types (MS1, MS2, MS3, and MS4), which can reflect the brain networks as well as their dynamic characteristic. Thus, the Williams Creative Tendency Scale (WCTS) and Rosenberg Self-esteem Scale (RSES) were used to investigate the modulating role of self-esteem on the relationships between trait creativity and the RS-EEG microstates. As our results showed, self-esteem consistently modulated the relationships between creativity and the duration and contribution of MS2 related to visual or imagery processing, the occurrence of MS3 related to cingulo-opercular networks, and transitions between MS2 and MS4, which were related to frontoparietal control networks. Based on these results, we thought that trait creativity was related to the executive control of bottom-up processing for individuals with low self-esteem, while the bottom-up information from vision or visual imagery might be related to trait creativity for individuals with high self-esteem.

6.
Sci Rep ; 10(1): 15710, 2020 09 24.
Article in English | MEDLINE | ID: mdl-32973269

ABSTRACT

Individuals with high neuroticism had the decreased control functions of anterior cingulate cortex (ACC) over amygdala (emotion regions) and low socioeconomic status (SES) had negative effects on the functions of ACC. Based on these, we hypothesized that the decreased functions of ACC might make individuals with low SES had high level of neuroticism. According to the score of objective SES (OSES) and subjective SES (SSES) scales, subjects were divided into four groups (low SSES, high SSES, low OSES and high OSES) to investigate the roles of dynamic characteristics related to the ACC in the relationships between SES and neuroticism using resting-state EEG (RS-EEG) microstates analysis. It had been found that RS-EEG microstates can be divided into four types (MS1, MS2, MS3 and MS4) and the MS3 was related cingulo-opercular brain networks (including ACC and anterior insular). As our prediction, SSES had direct effects on neuroticism relative to OSES. Moreover, the neuroticism for low SSES was positively related to the occurrence and contribution of MS3, as well as the possibilities of transitions between MS3 and MS1. Based on these, we thought that low-SSES individuals might be more difficult to inhibit the negative emotions, especially inhibit the spontaneous thoughts related to these emotions.


Subject(s)
Gyrus Cinguli/physiology , Neuroticism/physiology , Adolescent , Brain Mapping , Electroencephalography , Female , Humans , Male , Social Class , Socioeconomic Factors , Young Adult
SELECTION OF CITATIONS
SEARCH DETAIL
...