Energy & Environmental Science
·
2024
·Vol. 17
·期 4
·1416-1425
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IF 32.4
Jingdan Lei,Hexige Wuliji,Qingyong Ren,Xiaowen Hao,Hongliang Dong,Heyang Chen,Tian-Ran Wei,Jiawei Zhang,Pengfei Qiu,Kunpeng Zhao,Xun Shi
Advanced thermoelectric technology requires high-performance materials with exceptional electrical performance for large power output during service. AB2Sb2-type Zintl phases, especially Mg3Sb2, have attracted great attention recently because of the advantages of high-performance, low-cost and nontoxic components. Currently, remarkably high thermoelectric figures of merit zT values of 1.7–1.9 are reported in n-type Mg3Sb2-based materials, but they are quite low in p-type materials because of the small valence band degeneracy Nv and relatively high band effective mass . Here, we propose a band shaping strategy to effectively enhance the material's electrical transports. Through alloying Zn at the Mg2 sites of Mg3Sb2, double band degeneracy is achieved. Further alloying Yb at the Mg1 sites, band edge effective mass is greatly reduced. Combining the optimized carrier concentration by Li doping, the maximum power factor and zT values are increased to 15.9 μW cm−1 K−2 and 1.4, respectively, superior to those of the vast majority of reported p-type AB2Sb2 Zintl phases. This work demonstrates that band edge shaping is very successful for the optimization of electrical transport and thermoelectric performance in semiconductors.
研究领域:
凝聚态物理
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材料科学
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半导体物理
✓ 已验证
DOI
高影响因子
Surfaces and Interfaces
·
2024
·
IF 5.7
Zhonghui Han,Xiaobin Yang,Xinnan Shi,Leyao Wu,Peng Hu,Haibo Fan,Feng Teng
The band structure of heterojunction plays an important role in the performance of actual application and can be adjusted by the change of preparation condition. Herein, Cu 2 O nanofilms with different band structures were prepared via electrodeposition method by modifying the solution environment. With the value of pH increased from 7 to 12, the conductivity of the Cu₂O nanofilms shifted from n-type to p-type. Combined the obtained Cu 2 O film with TiO 2 nanoarray, the Cu 2 O/TiO 2 heterojunction were prepared. The photoelectrochemical performance of the Cu 2 O/TiO 2 heterojunction was affected by the interfacial band structure. The T7 sample has higher photocurrent (450 μA) caused by the unique S-scheme band structure, the T11 sample with a p-n junction structure takes second place (225 μA). The n-n type II heterojunction has the lowest photocurrent (20 μA). The Fermi level of Cu 2 O nanofilm was affected by the type of defects, such as oxygen and copper vacancies, leading to changes of band structure at the interface between Cu 2 O and TiO 2 . The obtained result further illustrates the importance of energy band engineering, and provides route and sight for the development and application of Cu 2 O/TiO 2 heterojunction.
研究领域:
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Lei Zhang,Zhiyuan Jiang,Jingru Guo,Chao Zhang,Xiaolong Xu,Dong Shi,Yongliang Shao,Zizheng Ai,Yongzhong Wu,Xiaopeng Hao
An in-depth understanding of structure-activity relationship between the phase constitution and solar-to-hydrogen (STH) conversion efficiency is conducive to guiding the optimization route of targeted photocatalyst candidates, further establishing advanced photocatalytic systems. Herein, based on the concept of phase engineering, we encompassed the crystalline phase of CdS and achieved precise regulation of phase proportion as well as phase boundary width in the phase junction for the first time. The above cooperative effect not only modifies energy band distribution for sufficient redox potentials, but also guarantees the reverse migration orientation of photogenerated carriers in phase junction, thereby endowing photocarriers with a prolonged lifetime. Compared to pure cubic or hexagonal phase (72.6 or 101.1 μmol h −1 g −1 ), this CdS system with optimized phase junction demonstrates an improved photocatalytic hydrogen evolution activity of 1.04 mmol h −1 g −1 and favorable stability without cocatalyst assistance, which mainly stems from an efficient protons reduction process interacting with long-lived photogenerated electrons. This research explores the mechanism behind phase regulation and its relationship with junction capability, providing a powerful strategy to manipulate crystal phase distribution and paving a feasible avenue for other phase-dependent photocatalysts towards rational design of heterostructures based on different phases in solar energy conversion field.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Small
·
2024
·
IF 13
Aizhu Chen,Xuhui Yang,Lijuan Shen,Ying Zheng,Min-Quan Yang
Loading cocatalysts onto semiconductors is one of the most popular strategies to inhibit charge recombination, but the efficiency is generally hindered by the localized built-in electric field and the weakly connected interface. Here, this work designs and synthesizes a 1D P-doped CdS nanowire/Ni 2 P heterojunction with gradient doped P to address the challenges. In the composite, the gradient P doping not only creates a funneled bandgap structure with a built-in electric field oriented from the bulk of P-CdS to the surface, but also facilitates the formation of a tightly connected interface using the co-shared P element. Consequently, the photogenerated charge carriers are enabled to be pumped from inside to surface of the P-CdS and then smoothly across the interface to the Ni 2 P. The as-obtained P-CdS/Ni 2 P displays high visible-light-driven H 2 evolution rate of ≈8265 µmol g −1 h −1 , which is 336 times and 120 times as that of CdS and P-CdS, respectively. This work is anticipated to inspire more research attention for designing new gradient-doped semiconductor/cocatalyst heterojunction photocatalysts with bridged interface for efficient solar energy conversion.
研究领域:
材料科学
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能源转换
·
光催化技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nanomaterials
·
2021
·Vol. 11
·期 11
·2940
·
IF 5.076
Bingke Zhang,Shengwen Fu,Dongbo Wang,Shujie Jiao,Zhi Zeng,Xiangyu Zhang,Zhikun Xu,Yaxin Liu,Chenchen Zhao,Jingwen Pan,Donghao Liu,Jinzhong Wang
The photocatalysis technique has been proven to be a promising method to solve environmental pollution in situations of energy shortage, and has been intensively investigated in the field of pollutant degradation. In this work, a band structure-controlled solid solution of BiOBrXI1−X(x = 0.00, 0.05, 0.10, 0.15, 0.20, 1.00) with highly efficient light-driven photocatalytic activities was successfully synthesized via simple solvothermal methods. The phase composition, crystal structure, morphology, internal molecular vibration, optical properties, and energy band structure were characterized and analyzed by XRD, SEM, HRTEM, XPS, Raman, and UV Vis DRS. To evaluate the photocatalytic activity of BiOBrXI1−X, rhodamine B was selected as an organic pollutant. In particular, BiOBr0.15I0.85displayed significantly enhanced photocatalytic activity by virtue of modulating the energy band position, optimizing redox potentials, and accelerating carrier separation. Moreover, the enhancement mechanism was elucidated on the basis of band structure engineering, which provides ideas for the design of highly active photocatalysts for practical application in the fields of environmental issues and energy conservation.Keywords:BiOBrXI1−X;solid solution;photocatalytic degradation;band structure engineering
研究领域:
环境科学
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材料科学
·
化学
✓ 已验证
DOI
PubMed
高影响因子
Applied Materials Today
·
2022
·
IF 8.663
Wei Jiao,Lili Zhang,Ruiquan Yang,Jing Ning,Lei Xiao,Yifan Liu,Jianyi Ma,Nasir Mahmood,Xian Jian
Increasing visible light absorption and constructing an active surface for TiO 2 have long been pursued to obtain high photocatalytic activities. Modifying TiO 2 at an atomic scale is desirable to optimize its surface state and band structure but remains a huge challenge. Herein, we developed an ultrasmall (∼5 nm) visible-light-responsive TiO 2 photocatalyst with a novel hybrid structure (TiO 2 /C) through a chemical vapor deposition process on large scale. Environmental in-situ transmission electron microscope studies confirmed the anatase TiO 2 with a monolayer carbon shell in a hybrid structure. The resulted structure possesses narrowed bandgap 2.83 eV, favoring the enhanced visible-light-responsive photocatalytic activity. Density functional theory (DFT) simulations confirm the tunable mechanism of carbon-induced localized energy band within the bandgap of TiO 2 . As a physical barrier without turning TiO 2 black, the monolayer carbon shell stabilizes Ti 3+ inside TiO 2, facilitates the separation of photo-induced carriers and enriches abundant absorbing sites of target pollutants. Consequently, the TiO 2 /C exhibits outstanding photocatalytic performance in both photoelectrochemical water oxidation and dye degradation under visible light besides superior activity for hydrogen evolution under simulated sunlight irradiation. This design proved a meaningful strategy in obtaining visible-light-responsive photocatalysts with a stable active surface for industrial application.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2014
·
IF 3.552
Yaru Ni,Wei Wang,Wenjuan Huang,Chunhua Lu,Zhongzi Xu
A new idea was employed to simultaneously reduce graphene oxide (GO) and wrap it on the surface of high-reactive anatase TiO 2 for fabricating novel TiO 2 -graphene (GP) hybrid materials. The process was based on the surface negatively charged property of GO. With the introduction of strong chemical interaction between TiO 2 and GP, the GP wrapped TiO 2 gives a strong red-shift of the light absorption edge and a further narrowed bandgap compared to that of GP randomly supported TiO 2 . This structure can also significantly enhance the separation efficiency of photogenerated electrons and holes. Furthermore, in contrast to the normal anatase TiO 2 , as-prepared TiO 2 is dominated with the high-reactive {0 0 1} facet. The superiority of the formed “core–shell” structure is confirmed by photocatalytic degradation of methylene blue (MB) under the xenon lamp and visible light irradiation. New photocatalytic mechanisms are also proposed based on the obtained results. This work may open a new doorway for new significant application of GP to prepare more GP-based high-reactive photocatalysts for environmental protection.
研究领域:
材料科学
·
环境科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Zhenyu Liu,Xiaoman Li,Senda Su,Wenming Ding,Linghu Meng,Yingying Wang,Mengyao Tan,Min Luo
Energy band engineering strategy by doping has been extensively proved to have great influence on photocatalytic properties of semiconductors. Herein, a novel Co-doped Bi 2 MoO 6 (Co-BMO) photocatalyst was developed for photocatalytic nitrogen fixation. Co-BMO with microsphere structure was synthesized by a one-step solvothermal method. The NH 3 yield of 0.3 % Co-BMO (130.07 μmol·h −1 ·g cat −1 ) was about 3.9 times higher than that of pure BMO without scavengers and visible light irradiation. The band gap of 0.3 % Co-BMO was reduced and the average PL lifetime was improved due to the successful doping of Co 2+ , which directly led to higher separation efficiency of photogenerated carriers and improved photocatalyst activity. In addition, gas chromatography (GC) tests showed that 0.3 % Co-BMO had a higher photocatalytic oxygen production capacity, which meant that more protons would be involved in the nitrogen reduction reaction . Their synergistic effect greatly enhanced the photocatalytic nitrogen fixation ability of 0.3 % Co-BMO. This novel photocatalyst may be a promising candidate for photocatalytic nitrogen fixation.
研究领域:
材料科学
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环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2021
·
IF 19.503
Peijie Ma,Xu Zhang,Cong Wang,Zhiwei Wang,Kaiwen Wang,Yibo Feng,Jiaxing Wang,Yadi Zhai,Jiguang Deng,Lihua Wang,Kun Zheng
Polymeric carbon nitride (C 3 N 4 ) is a very attractive candidate to produce photocatalytic hydrogen peroxide (H 2 O 2 ) due to its low-cost, metal-free characteristics. However, the low efficiency would limit its development to higher yields because of insufficient light absorption and electron-hole separation. Here, we developed a simple method to anchor CN quantum dots (QDs) onto g-C 3 N 4 nanosheets to form a homojunction structure (HJ-C 3 N 4 ), which could improve photocatalytic performance largely without introducing metal elements. Its superior efficiency is a result of the band alignment by the homojunction structure providing excellent electron-hole separation and QDs providing suppressed recombination. Simultaneously, the light responsiveness of QDs endows a wide spectrum-responsive adsorption and enhances the adsorption intensity. The H 2 O 2 yield of the HJ-C 3 N 4 reached 115 μmol L −1 h −1 in pure water by visible light, which has an 8.6x higher production than g-C 3 N 4 nanosheets . The material design of 0D/2D homojunction could be extended to other materials with specific band alignment.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2024
·
IF 10.7
Zhengjie Su,Xinru Wu,Dong-Hau Kuo,Baoqian Yang,Binghong Wu,Longyan Chen,Pengkun Zhang,Jinguo Lin,Dongfang Lu,Xiaoyun Chen
Herein, an Ag/S co-doped Bi2O3-based sulfur oxide catalyst was prepared via a facile green method. The Ag/S–Bi2O3 catalyst with suitable Ag/S doping demonstrated super visible light photocatalytic hydrogen evolution (PHE) at 7.52 mmol g−1 h−1, with an apparent quantum efficiency (AQE) of 8.67% at 420 nm. Ag/S co-doping can adjust the energy band structure of an oxidation type Bi2O3 catalyst, converting it into a visible light hydrogen production catalyst suitable for hydrogen production. Sulfur doping adjusts the content of oxygen vacancies to enhance the surface active sites, and the introduction of noble metal silver endows the catalyst with more excellent electrical conductivity and electron trapping ability. Thus, Bi2O3 with Ag/S co-doping produced a suitable energy band structure, enhanced the content of oxygen vacancies and the number of surface active sites, and endowed the catalyst with excellent electrical conductivity and electron trapping ability, significantly producing catalysts with excellent visible light PHE activity. Furthermore, Ag/S–Bi2O3-3 exhibited super visible light PHE activity and excellent stability and persistence and is expected to play a potential role in the field of PHE reactions (PHERs).
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
OPTICAL MATERIALS
·
2021
·
IF 3.08
Tingting Li,Chengcheng Sun,Chang Xue,Yutao Jiang,Jian Zhang,Lijuan Zhao
Iron (Fe) doped ZnSe microspheres were fabricated by solvothermal method . X-ray diffraction (XRD), Raman analysis, Fourier transform infrared (FT-IR) spectra and X-ray photoelectron spectroscopy (XPS) results indicate that Fe 2+ cations were incorporated into the zinc blende ZnSe lattices successfully and uniformly distributed in sample. SEM images displayed that doping with Fe 2+ cations did not change the morphology of microspheres . The growth mechanism of Fe-doped ZnSe microspheres was proposed. The band gap increases and photoluminescence (PL) peaks in visible region show blue-shift as doping with Fe ions . In addition, a reduction in PL lifetimes in visible range was also observed, which may be due to the increase in non-radiative energy transfer between Fe 2+ doping in the ZnSe matrix. The 5 E↔ 5 T 2 transition of Fe 2+ in the 3.6–5.5 μm spectral range was observed in Fe-doped sample at low temperature.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2018
·Vol. 6
·期 19
·9057-9063
·
IF 9.931
Xu Zhang,Yu-Zhu Zhou,De-Yao Wu,Xiao-Hua Liu,Rui Zhang,Hui Liu,Cun-Ku Dong,Jing Yang,Sergei A. Kulinich,Xi-Wen Du
Zinc oxide is a cost-efficient and eco-friendly material for solar-to-chemical energy conversion. However, the relatively wide band gap and poor stability restrict its practical applications. Herein, we report on the modification of ZnO nanosheets with a porous atomically thin ZnS overlayer. The as-prepared ZnS/ZnO/ZnS sandwich nanosheets exhibit a reduced band gap (2.72 eV) and yet a slightly elevated conduction band minimum, which remarkably broadens the wavelength range for light absorption and generates electrons with enough reducing capability. At the same time, the newly-prepared sandwich nanosheets possess alternatively exposed ZnS and ZnO surface patches, which attract and accommodate photo-generated holes and electrons, respectively. In addition, the ZnS overlayer catalyzes and accelerates hole-consumption reactions, thus preserving electrons for efficient water splitting. As a result, the ZnS/ZnO/ZnS sandwich nanosheets demonstrate intensive light absorption, fast charge separation, long electron lifetime, and eventually the highest hydrogen production rate reported for oxide catalysts so far. This work proves that passivation with an ultrathin layer is a potent approach for energy-band engineering, and semiconductor sandwich nanostructures are promising for highly efficient water splitting under sunlight.
研究领域:
材料科学
·
能源转换
·
光催化技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）