APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Shuo Li,Yahui Li,Juan Zhang,Xiutao Liu,Kaixin Zhang,Yu Zhang,Xi-ming Song
A CoOOH cocatalyst overlayer is electrochemically deposited on the BiVO 4 surface, and thermal annealing converted CoOOH to Co 3 O 4 in situ. The primary difference between the two cocatalysts lies in their electrolyte permeabilities, resulting in significant differences in their thermodynamic effects on enhancing the photoelectrochemical water oxidation performance. We proved that the CoOOH cocatalyst is unable to achieve true chemical passivation of the surface states of the BiVO 4 photoanode, whereas the Co 3 O 4 cocatalyst can chemically passivate the surface states. Nevertheless, the CoOOH cocatalyst still exhibits better water oxidation performance than Co 3 O 4 , which is attributed to the fact that the permeable CoOOH cocatalyst can accumulate more photogenerated holes in the bulk phase and provide more active sites. However, the CoOOH cocatalyst still exhibits better water oxidation performance compared to Co 3 O 4 , which is attributed to the permeable CoOOH cocatalyst can accumulate more photogenerated holes in its bulk phase and offer more active sites.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2019
·Vol. 19
·期 6
·3437-3446
·
IF 1.093
Niu Yakun,Zhou Yi,Niu Ping,Shen Haiyan,Ma Ying
Ti doped hematite photoanodes have been intensively investigated due to their excellent activity for photoelectrochemical water oxidation. However, little attention has been paid to the doping effect on the photocurrent onset potential of hematite and the underlying mechanism. In this
paper, Ti doped hematite nanorod arrays were successfully prepared through a facile treatment of hematite with TiCl3 solution. The photocurrent of the Ti doped hematite photoanode increases by three times, and its onset potential shifts more positively as compared with that of the
undoped one. Electrochemical analyses were employed to unravel the mechanism of anodic shift of the onset potential. Cyclic voltammograms and electrochemical impedance spectra confirmed that more surface states were formed in Ti doped hematite than the undoped one. As a result, lower activity
towards oxygen evolution reaction (OER) and increased electron–hole recombination after light on/off in low potential region were observed in Ti doped hematite. It is concluded that these doping induced surface states may be a hindrance to charge transfer and the onset potential of Ti
doped hematite shifts anodically.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2022
·
IF 5.518
Xiaoyi Lu,Shangshang Zhang,Weiguang Shi,Dan Cheng,Hong-Wei Li,Shihan Xu,Biao Dong
Carbon dots (CDs) are important zero-dimensional materials with excellent luminescent properties. However, the mechanism of CDs photoluminescence is still an open debate, which significantly hinders the development of CDs with desired optical properties. In this work, bright blue fluorescent carbonized 1.0 G polyamine-amine polymer dots (NCPDs) has been prepared by a simple hydrothermal method, with a quantum yield of 57 %. The dominant luminescence of the NCPDs is attributed to the surface states based on synergistic hybridization between the carbon backbones and connected functional groups at below 120 °C. Photoluminescence transforms from the surface states to the surface - carbon core states, and then to carbon core states from 120° to 150 °C. Meanwhile, the degree of carbonization increases along with the size of NCPDs growing from 1.36 to 3.20 nm, and the NCPDs present excitation-dependent emission properties. Due to the remarkable fluorescence property of NCPDs, Cu 2+ determination has been carried out in the aqueous phase, and the detection limit is 9 nM, which is much lower than the international minimum standard (20 μM). NCPDs present high selectivity and sensitivity toward detecting Cu 2+ , and provide potential applications in detecting metal pollution in the environmental water.
研究领域:
材料科学
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环境科学
✓ 已验证
DOI
高影响因子
Small
·
2014
·Vol. 10
·期 15
·3099-3109
·
IF 7.514
Lian Hu,Huizhen Wu,Bingpo Zhang,Lingxiao Du,Tianning Xu,Yongyue Chen,Yong Zhang
We explore a strongly interacting QDs/Ag plasmonic coupling structure that enables multiple approaches to manipulate light emission from QDs. Group II–VI semiconductor QDs with unique surface states (SSs) impressively modify the plasmonic character of the contiguous Ag nanostructures whereby the localized plasmons (LPs) in the Ag nanostructures can effectively extract the non-radiative SSs of the QDs to radiatively emit via SS–LP resonance. The SS–LP coupling is demonstrated to be readily tunable through surface-state engineering both during QD synthesis and in the post-synthesis stage. The combination of surface-state engineering and band-tailoring engineering allows us to precisely control the luminescence color of the QDs and enables the realization of white-light emission with single-size QDs. Being a versatile metal, the Ag in our optical device functions in multiple ways: as a support for the LPs, for optical reflection, and for electrical conduction. Two application examples of the QDs/Ag plasmon coupler for optical devices are given, an Ag microcavity + plasmon-coupling structure and a new QD light-emitting diode. The new QDs/Ag plasmon coupler opens exciting possibilities in developing novel light sources and biomarker detectors.
研究领域:
光学
·
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nanoscale
·
2022
·Vol. 14
·期 45
·17044-17052
·
IF 8.307
Lili Gao,Peng Wang,Huan Chai,Shuwen Li,Jun Jin,Jiantai Ma
Regarding the indirect hole transfer route in hematite-based photoelectrodes, the widely accepted viewpoint is that the FeIVO states act as a hole transfer medium, while other types of surface states act as recombination centers. Alternatively, it has rarely been reported that the recombining surface states may contribute to the charge transport in modified photoelectrodes. In this study, we employed CoCr layered double hydroxide (LDH)/Fe2O3 and CoCr LDH/Zr:Fe2O3 as research models to investigate the distinct charge transfer pathways in composite photoanodes. Different from the adverse role of surface states at ∼0.7 V versus the reversible hydrogen electrode (r-SS) in the bare hematite photoelectrodes (Fe2O3 or Zr:Fe2O3), the r-SS in the composite photoanodes (CoCr LDH/Fe2O3 or CoCr LDH/Zr:Fe2O3) served as a hole transfer station to induce high-valent Co cations, and the position of r-SS determined the onset potential of the composite photoelectrodes. Moreover, the FeIVO states still acted as active intermediates to transport numerous holes to the cocatalyst, which enhanced the charge utilization efficiency at 1.23 V versus the reversible hydrogen electrode (RHE) to a large extent. Besides, a noteworthy fact is that Zr doping increased the number of active FeIVO states, which significantly contributed to the enhancement in current density. However, it led to a delayed onset potential because of the positively shifted surface states (r-SS and FeIVO). Evidently, the different surface state distributions between Fe2O3 and Zr:Fe2O3 gave rise to anisotropic charge transfer and recombination behavior in the composite photoanodes. This study gives extensive insight into the hole transfer route in composite photoanodes and reveals the surface state-tuning effects of dopants and cocatalysts, which are significant for a deep understanding of the surface states and optimal design of composite photoanodes via surface state modulation.
研究领域:
材料科学
·
光电化学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Ruikai Wang,Zhichao Hao,Haiyan Li,Chenghui Xia,Bohua Dong,Lixin Cao
Optimizing the interfacial action of photoanode for photoelectrochemical (PEC) behavior to facilitate charge transport is essential for enhancing solar-to-fuel efficiency. Herein, a typical CuWO 4 /NiFe-LDH/Ag photoanode was reported and an alternative pathway for charge transfer in the PEC process through surface states mechanism was elucidated. In particular, the layer double hydroxides (NiFe-LDH) acted as charge-transfer agents to facilitate the transfer of photogenerated carriers; while the surface plasmon resonance (SPR) effect of the Ag provided hot electrons, which increased the carrier concentration and promoted the charge separation. The influence of presence of surface states on the PEC process was systematically illustrated. Experimental results indicated that the optimized CuWO 4 /NiFe-LDH/Ag photoanode displayed a photocurrent that was more than an order of magnitude larger than that of the pure CuWO 4 (increasing from 0.30 mA cm −2 to 1.45 mA cm −2 at 1.23 V vs. RHE), accompanied by favorable electrochemical impedance and stability (maintaining 92.4%). Importantly, increasing the available filled surface states could be beneficial in enhancing the PEC behavior. This work provided additional insights into photoanode charge transport in PEC processes.
研究领域:
材料科学
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能源科学
·
光催化
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2018
·Vol. 6
·期 22
·10456-10465
·
IF 9.931
Xiaohui Zhong,Huichao He,Minji Yang,Gaili Ke,Zongyan Zhao,Faqin Dong,Bowen Wang,Yaqi Chen,Xianying Shi,Yong Zhou
BiVO4 is a promising photoanode material for photoelectrochemical water splitting, but its actual activity is hindered by the high energy surface states. Here, we report that In3+ can be used as a dopant to substitute the partial sites of Bi3+ in BiVO4 for modifying the surface states and improving the water oxidation activity of a BiVO4 nanoflake film. Among the In3+-doped BiVO4 film photoanodes, the 7% In3+-doped BiVO4 film shows optimal photoelectrochemical water oxidation activity. At 1.23 V vs. RHE, the 7% In3+-doped BiVO4 photoanode exhibits a photocurrent density of 1.56 mA cm−2 in 0.1 M Na2SO4, which is over 200% greater than that of the undoped BiVO4 photoanode. In3+-doping did not change the morphology, phase and band gap of BiVO4 obviously, but resulted in a positive shift of the flat band position and higher surface charge separation efficiency for water oxidation. Density functional theory calculations indicate that the surface energy of BiVO4 decreased after In3+-doping that involved more unsaturated electrons of the Bi atom in the Bi–O bonds, thus reducing the amount of exposed unsaturated Bi atoms and broken Bi–O bonds. Therefore, the enhanced water oxidation activity on the In3+-doped BiVO4 photoanode can be ascribed to In3+-doping that passivated the surface states of BiVO4 and thus inhibited the surface charge recombination.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
Materials Research Express
·
2021
·Vol. 8
·期 8
·085002
·
IF 1.62
Xiangming Liu,Xiaoshi Peng,Tao Xu,Yulong Li,Huiyue Wei,Zanyang Guan,Feng Wang
Ternary Ag-In-S and quaternary Ag-In-Zn-S nanoparticles with different ratio of Ag/In/Zn/S are synthesized. The incorporation of Zn into Ag-In-S nanoparticles leads to the increase in the optical bandgap and the blue shift of photoluminescence (PL). The optical properties of these nanoparticles are significantly dependent on the chemical composition of nanoparticles. Time-resolved PL spectroscopy in nanosecond time regime is used to study the recombination processes of carriers, which involve the surface states and intrinsic crystallographic defects. These measurements support the donor-acceptor model, in which the PL is achieved by radiative recombination of the localized electron and hole.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2019
·
IF 2.961
Huanhuan Xu,Lihe Yan,Jinhai Si,Xiaoyu Li,Yanmin Xu,Xun Hou
Carbon nanodots have been demonstrated to be an effective reducing agent in fabricating silver nanoparticles . In this study, the dependence of reduction efficiency of the CDs on the irradiation wavelength and their photoluminescence property is investigated. We find that the CDs excited by short wavelength light shows much higher photoreducibility than those excited by longer wavelength irradiation, although their PL intensity might be about the same. By analyzing the PL and the time-resolved PL property of the formed CDs-Ag NPs composites we find that, when the CDs are excited, there are two kinds of recombination path ways of the carriers contributing to their photoluminescence: the direct excitation of surface states, and the excited electrons from carbonic-core transferred to the surface states; only the electrons originates from the intrinsic carbonic-core excited by short wavelength can reduce the Ag ions , while those originates from the direct excitation of the surface states by long wavelength light are ineffective. The proposed reduction kinetics of Ag ions is significant to understand the photoreduction property of the CDs.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2017
·Vol. 5
·期 41
·10785-10793
·
IF 5.256
Lei Han,Shi Gang Liu,Jiang Xue Dong,Jia Yu Liang,Ling Jie Li,Nian Bing Li,Hong Qun Luo
The facile and effective synthesis of truly multicolor photoluminescent (PL) polymer carbon dots (PCDs) is still a considerable challenge. Here, a mild and facile synthetic method to prepare multicolor emissive PCDs by self-oxidation and autopolymerization using hydroquinone and ethylenediamine as precursors is reported. The resulting PCDs were separated via silica-gel column chromatography, which gave three types of PCDs emitting bright and stable yellow, green, and blue fluorescence. The three types of PCDs exhibited attractive features such as excellent solubility, excitation wavelength-independent photoluminescence, high stability, monoexponential fluorescence lifetimes, and homogeneous optical properties. The uniform optical properties of the as-prepared PCDs helped us to explore their multicolor emissive PL mechanism. Detailed characterization and investigation of the PCDs revealed that their surface state was primarily responsible for the observed multicolor emissive photoluminescence. A PL mechanism that involved control of the energy gap by the surface state was proposed to explain the effect of the surface functional groups on the PL properties of the PCDs. The emission of the PCDs was strongly associated with the CN functional groups on their surface. The band gap narrowed with increasing content of CN on the PCD surface, resulting in the red shift of the PL emission peak.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Kangwang Wang,Longfu Li,Peifeng Yu,Nannan Tang,Lingyong Zeng,Kuan Li,Chao Zhang,Rui Chen,Zaichen Xiang,Huichao Wang,Yongqing Cai,Kai Yan,Huixia Luo
Topological semimetals with protected surface states mark a new paradigm of research beyond the early landmarks of band-structure engineering, allowing fabrication of efficient catalyst to harness the rich metallic surface states to activate specific chemical processes. Herein, we demonstrate a facile solid-phase method for in-situ doping of Ir at the Os sites in the Os 3 Sn 7 , an alloy with topological states, which significantly improves the photocatalytic performance for the reduction of CO 2 to CO and CH 4 . Experimental evidence combined with theoretical calculations reveal that the nontrivial topological surface states greatly accelerate charge-separation/electron-enrichment and adsorption/activation of CO 2 molecules, rendering highly efficient reaction channels to stimulate the formation of *COOH and *CO, as well CHO*. This work shows the promise of achieving high photocatalytic performances with synthesizing topological catalysts and provides hints on the design of novel topological catalysts with superior photoactivity towards the CO 2 reduction reaction.
研究领域:
材料科学
·
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2021
·
IF 4.311
Minhua Ai,Xidi Li,Lun Pan,Xiaoting Xu,Jin Yang,Ji-Jun Zou,Xiangwen Zhang
Sluggish interfacial carrier transfer and oxygen production kinetics of photoelectrochemical water splitting are related to the Fermi-level pinning of the hematite surface states, thus it requires extra energy input and results in low PEC efficiency. Here we develop a facile secondary calcination strategy for regulating the density and distribution of surface states in hematite photoanode system. The fabricated α-Fe 2 O 3 -450 possesses significantly reduced disordered layers and renovated surface oxygen vacancy structure to increase carrier density and effectively passivate surface trapping states. Thus, both bulk and interfacial recombination of electrons and holes are effectively suppressed, and the quasi-hole Fermi level moves to more positive position, leading to a large photovoltage for reducing kinetic overpotential. Therefore, the photocurrent density of α-Fe 2 O 3 -450 (1.035 mA cm −2 ) is 1.8 times higher than that of pristine α-Fe 2 O 3 (0.58 mA cm −2 ) at 1.23 V versus reversible hydrogen electrode, and α-Fe 2 O 3 -450 has more cathodic onset potential than α-Fe 2 O 3 .
研究领域:
材料科学
·
电化学
·
可再生能源
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）