Nanoscale
·
2015
·Vol. 7
·期 13
·5767-5775
·
IF 7.394
Ping Wang,Jie Zhang,Haili He,Xiaolong Xu,Yongdong Jin
The use of colloidal semiconductor nanocrystals (NCs), especially those with a core/shell structure, for photocatalytic hydrogen (H2) production from water is currently one of the hottest research fields. Although the ligand on the semiconductor NC surface is crucial to the optical and optoelectronic properties of the NC, the study of the ligand effect on the photocatalytic activity of H2 generation is rarely reported. Herein, we employ nearly monodispersed CdSe/CdS core/shell NCs as a model photocatalytic system, and three kinds of ligands with different numbers of functional thiol groups (i.e., poly(acrylic acid), 3-mercaptopropionic acid and 2,3-dimercaptosuccinic acid) are selected as the ligands to investigate the effect of ligand on the efficiency of H2 photogeneration. The results show that the H2 photogeneration efficiency is highly dependent on the surface ligand of the NCs, and it increases with the increase of the number of the functional thiol groups in the ligand, and correspondingly, the photoluminescence intensity and average fluorescence lifetime, which are measured by steady state and time-resolved fluorescence measurements, are decreased. The surface trap-related charge separation efficiency, which is mediated by surface coating with different ligands, is supposed to cause the distinct ligand-dependent performance in the H2 evolution.
研究领域:
材料科学
·
光化学
·
纳米技术
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ACS Applied Energy Materials
·
2021
·
IF 6.024
Jun Zhang,Shuai Shao,Desen Zhou,Tingmin Di,Tielin Wang
Two-dimensional (2D) layered nanocomposite provides a surface-to-surface heterojunction, which is an effective way to improve the photocatalytic performance because larger contact areas can promote the separation rate of interfacial charge carriers. In this study, Co(OH)2/g-C3N4/Ni(OH)2 2D layered photocatalysts have been successfully synthesized through a simple precipitation–hydrothermal method. The composite achieves a high H2-production rate of 899 μmol·h–1·g–1, which exceeds the rate of samples only coupled with Co(OH)2 and Ni(OH)2 by 4.0 and 1.9 times, respectively. In addition, the activity is even higher than that of the optimized Pt-g-C3N4 sample (1 wt. % Pt–C). The characterization results reveal the close contact of g-C3N4 and Ni/Co hydroxides, and such a face-to-face contact can greatly improve the interfacial charge-transfer rate, resulting in a high photocatalytic performance. This work demonstrates a simple way to enhance the photocatalytic H2 production of g-C3N4 under the cooperative effect of Co(OH)2 and Ni(OH)2 and provides novel insights into constructing other 2D ternary heterostructure nanocomposites.
研究领域:
材料科学
·
催化化学
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Journal of Energy Chemistry
·
2020
·
IF 7.216
Xuedong Jing,Na Lu,Jindou Huang,Peng Zhang,Zhenyi Zhang
Engineering lattice defects in two-dimensional (2D) sulfide semiconductors has been accepted as an effective strategy to enhance the efficiency of the solar-to-fuels conversion. Although many researches have proven the lattice defect-mediated photocatalytic activity of ZnIn 2 S 4 , the artificial control of S-defects for optimizing the charge-carrier kinetics process in ZnIn 2 S 4 has long been a challenging task. Herein, we report a facile one-step method to modulate the lattice S-content of ZnIn 2 S 4 microflowers (MFs) only through adjusting the used amount of S-precursor in the hydrothermal solution that contains the metal precursors with a fixed Zn/In stoichiometric ratio at 1:2. We also demonstrated that the S-vacancies at the In facets were the main type of lattice defects in the formed ZnIn 2 S 4 MFs, which could enhance both the separation and migration processes of the photoinduced charge-carriers due to the existence of discrete defect energy-levels (DELs) and the reduced effective mass of electrons, as evidenced by the first-principles calculations and the electron spectra analyses. The ZnIn 2 S 4 MFs with the optimal content of S-vacancy obtained by a hydrothermal treatment of the precursors with the Zn/In/S stoichiometric ratio of 1:2:8 possessed the long-lived photoinduced electron (~94.64 ns) for contributing to the photo-physical and -chemical processes. Thus, upon visible light irradiation, the H 2 -evolution rate of this sample reached ~ 2.40 mmol h −1 g −1 with an apparent quantum efficiency of ~ 0.16% at 420 nm even though only using 5 mg of photocatalysts without any cocatalysts .
研究领域:
材料科学
·
能源化学
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Applied Materials Today
·
2023
·
IF 8.3
Guiyang Yu,Ke Gong,Lan Hu,Chuanwang Xing,Yujia Hu,Debao Wang,Xiyou Li
The development of mild and environmental method for direct transformation of aromatic alcohol into hydrobenzoin via controlled C‒C coupling is a highly attractive but challenging goal. In this paper, a P-doped g-C 3 N 4 photocatalyst with NiS nanoparticles modification is first reported to apply the visible-light-driven C‒C coupling of aromatic alcohol into hydrobenzoin, as well as integrating with the production of clean H 2 fuel. The synergistic effect of doped P atoms and formed type-II heterojunction between PCN and NiS improves the light absorption ability of g-C 3 N 4 and greatly suppresses the charge recombination. Optimized 2.0% NiS/PCN composite achieves the complete conversion of aromatic alcohol within 6 h reaction time, as far as we known, which is the highest efficiency so far for aromatic alcohol conversion via photocatalytic strategy. Hydrobenzoin is controllably formed with 68% selectivity, together with a highly-efficient H 2 production rate of 994.8 μmol·g −1 ·h −1 . In-situ EPR studies reveal a preferential activation of C‒H bond than O‒H bond in aromatic alcohol by photoexcited holes, forming C 6 H 5 ĊH 2 OH radicals for subsequent coupling. The residual protons interact with photoexcited electrons to generate H 2 . Our study not only offers an efficient g-C 3 N 4 -based photocatalyst for the synthesis of hydrobenzoin under mild conditions, but also opens up a new avenue for manipulating the activation of C‒H or O‒H bonds for high selectivity of hydrobenzoin product.
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Nano Research
·
2023
·Vol. 16
·期 5
·6278-6289
·
IF 9.9
Xu Jialun,Zhang Zhihua,Yu Daiyi,Du Wei,Song Nan,Duan Xuezhi,Zhou Xinggui
The catalytic performances over propylene epoxidation with H 2 and O 2 (HOPO process) are significantly affected by the properties (e.g., surface properties, Ti coordination, and morphology) of titanosilicate zeolite. Introducing urea into zeolite synthesis is a simple and convenient method to modify these properties of titanosilicate zeolite. Uncalcined pore-blocked titanium silicalite-1 (TS-1, i.e., TS-1-B) with the lower urea dosage possesses more defective structure and unsaturated coordinated Ti sites verified by 29 Si nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) analysis, which results in a high initial activity and hydrogen efficiency; while the high surface acidity generated by these Ti species leads to a continuous decrease in the activity and the propylene oxide (PO) selectivity during the reaction. As the amount of urea gradually increases, the TS-1-B samples present the reduced surface defects and defective and unsaturated Ti species. Specially, TS-1-B-0.30U presents the weaker PO adsorption on PO-diffusion reflectance infrared Fourier transform spectra (DRIFTS), and thus results in the high stable PO formation rate and selectivity over its Au catalyst. Furthermore, a flat-plate-like shape with a shorter thickness of 100 nm along the b-axis direction is observed on the urea-modified TS-1. Compared with the conventional ellipsoidal TS-1 with crystal sizes of 200 and 500 nm, the flat-plate-like TS-1-0.30U displays the less surface defects, unsaturated Ti species, and the weaker Lewis acid, which is favorable for the desorption and intracrystalline diffusion of PO, thus reduces the occurrence of side reactions for the improved selectivity and stability. This work may provide a reference for developing titanium-containing materials with high activity and stability over HOPO reaction.
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Science China-Materials
·
2023
·Vol. 66
·期 6
·2274-2282
·
IF 8.1
Zhang Yang,Cao Ning,Liu Xiaoming,He Fengting,Zheng Bin,Zhao Chaocheng,Wang Yongqiang
Graphite carbon nitride (g-C 3 N 4 ) has become an emerging metal-free photocatalyst and attracted the attention of researchers. However, pure g-C 3 N 4 (PCN) prepared by traditional thermal condensation polymerization has a low polymerization of heptazine ring chains and a large number of charge recombination centers, which hinder in-plane charge transport, leading to undesirable photocatalytic performance. Herein, PCN fabrication by thermal treatment with ammonium oxalate monohydrate was performed to produce highly dispersed porous g-C 3 N 4 nanosheets, and the integrity of their in-plane heptazine ring chains was successfully improved without introducing heteroatoms. Electron paramagnetic resonance and 13 C nuclear magnetic resonance analyses revealed significantly increased electron density and delocalization of the π-conjugated structure. The obtained samples exhibited acceptable stability and photocatalytic activity, and the hydrogen reduction rates without and with the Pt co-catalyst were 11.2 and 5.3 times that of PCN.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Xiangyu Zhou,Jingbo Wu,Yan Xiao,Yinhua Jiang,Wenli Zhang,Yan Liu,Zhanchao Liu,Jianming Zhang
Reasonable design and construction of heterogeneous photocatalysts with close interface contact are considered as the effective strategy to realize the application of highly efficient solar for hydrogen evolution and pollutant degradation. Here, a novel Zn 0.5 Cd 0.5 S nanospheres/Sn 3 O 4 nanosheets (ZCS/SO) heterostructure photocatalyst was firstly synthesized using a simple hydrothermal method, where Zn 0.5 Cd 0.5 S nanospheres in-situ grew on the surfaces of Sn 3 O 4 nanosheets derived by ultrasonicating Sn 3 O 4 nanoflowers. The synthesized ZCS/SO heterostructure exhibited much higher photocatalytic activity for H 2 production and tetracycline hydrochloride (TCH) degradation than pristine Sn 3 O 4 and Zn 0.5 Cd 0.5 S. The optimal ZCS/SO-10 performed the highest rate of hydrogen production of 7.19 mmol·g −1 ·h −1 , which was 112.3 and 3.6 times those of Sn 3 O 4 and Zn 0.5 Cd 0.5 S, respectively. And the AQY of ZCS/SO-10 for H 2 evolution was up to 16.6 % at λ = 420 nm. Moreover, ZCS/SO-10 displayed the highest TCH degradation rate (0.0484 min −1 ), which were 228.3 and 1.9 times those of Sn 3 O 4 (0.000212 min −1 ) and Zn 0.5 Cd 0.5 S (0.0249 min −1 ). Such excellent dual-functional photocatalytic performance of ZCS/SO heterostructure could be attributed to the synergistic effect between Sn 3 O 4 and Zn 0.5 Cd 0.5 S as well as the formation of heterogenous interfaces with close contacts, which greatly increased specific surface area, enlarged spectral response range, enhanced hydrophilicity and accelerated photogenerated charge transfer, resulting in the improvement of photogenerated charge yield and photoreaction efficiency. Detailed electron transport mechanisms and possible degradation paths of TCH were also proposed. This work provides a feasible strategy for the preparation of transition metal sulfide photocatalysts efficiently utilizing solar energy to realize the production of clean energy and water environmental remediation.
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Small
·
2023
·
IF 13.3
Mengxiao Zhong,Junyu Yang,Meijiao Xu,Siyu Ren,Xiaojie Chen,Ce Wang,Mingbin Gao,Xiaofeng Lu
Rational designing electrocatalysts is of great significance for realizing high-efficiency H 2 production in the water splitting process. Generally, reducing the usage of precious metals and developing low-potential nucleophiles oxidation reaction to replace anodic oxygen evolution reaction (OER) are efficient strategies to promote H 2 generation. Here, NiS-coated nickel–carbon nanofibers (NiS@Ni-CNFs) are prepared for low-content Pt deposition (Pt-NiS@Ni-CNFs) to attain the alkaline HER catalyst. Due to the reconfiguration of NiS phase and synergistic effect between Pt and nickel sulfides, the Pt-NiS@Ni-CNFs catalyst shows a high mass activity of 2.74-fold of benchmark Pt/C sample. In addition, the NiS@Ni-CNFs catalyst performs a superior urea oxidation reaction (UOR) activity with the potential of 1.366 V versus reversible hydrogen electrode (RHE) at 10 mA cm −2 , which demonstrates the great potential in the replacement of OER. Thus, a urea-assisted water splitting electrolyzer of Pt-NiS@Ni-CNFs (cathode)||NiS@Ni-CNFs (anode) is constructed to exhibit small voltages of 1.44 and 1.65 V to reach 10 and 100 mA cm −2 , which is much lower than its overall water splitting process, and presents a 6.5-fold hydrogen production rate enhancement. This work offers great opportunity to design new catalysts toward urea-assisted water splitting with significantly promoted hydrogen productivity and reduced energy consumption.
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PubMed
高影响因子
INORGANICA CHIMICA ACTA
·
2023
·
IF 2.8
Meifeng Chen,Tingting Xiao,Yuanfei Huang,Xiaosong Zhou,Jin Luo,Xunfu Zhou,Yuanyuan Ge
Research on the subject of photolysis focuses on the creation of effective non-precious metal co-catalysts. Graphitic carbon nitride (g-C 3 N 4 ) is a promising candidate for photocatalytic hydrogen generation from water. But its photocatalytic activity is limited by the slow redox reaction, high carrier recombination rate, and inadequate optical absorption. Incorporating in situ loading Ni 2 P/Cu 3 P and phosphorus doping on g-C 3 N 4 is effective in overcoming the drawbacks. Phosphorus doping reduces the band gap of g-C 3 N 4 for increased light absorption and improves the separation of photogenerated charge. Additionally, Ni 2 P/Cu 3 P heterojunctions anchored on P-doped g-C 3 N 4 (P-C 3 N 4 ) as non-noble co-catalysts boost light adsorption, enabling charge transfer and speeding the hydrogen evolution process. The resultant Ni 2 P/Cu 3 P@P-C 3 N 4 composite photocatalyst achieves an effective photocatalytic hydrogen evolution rate of 201 times greater than that of g-C 3 N 4 (12.9 μmol·h −1 ·g −1 ). This work is instructive to develop efficient g-C 3 N 4 -based photocatalysts for photocatalytic water splitting without the need for noble metals.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2022
·
IF 24.319
Lili Guo,Jingqi Chi,Jiawei Zhu,Tong Cui,Jianping Lai,Lei Wang
Seawater electrolysis is an efficient method for producing carbon-neutral hydrogen; however, it is hindered by high energy cost and chlorine evolution reaction. In this study, we report Ru, P dual-doped NiMoO 4 multichannel nanorods in-situ grown on nickel foam (Ru/P-NiMoO 4 @NF), which can achieve chlorine-free hydrogen production by coupling seawater splitting with thermodynamically favorable urea oxidation . The Ru/P-NiMoO 4 @NF exhibits bifunctional activity with working potentials of 0.23 V to deliver 3000 mA cm −2 for HER and 1.46 V to deliver 1000 mA cm −2 for UOR. The overall urea splitting system in the two-electrode electrolyzer require low voltage of 1.73 V to drive 500 mA cm −2 , and demonstrate remarkable durability to keep above 100 mA cm −2 for 145 h. Density functional theory calculations reveal that dual-doping modulate the d -band center of catalyst, thus enhancing the adsorption of reactants and intermediates. This work provides information for designing catalysts for combing seawater splitting with urea purification.
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JOURNAL OF PHYSICS D-APPLIED PHYSICS
·
2022
·Vol. 55
·期 44
·444008
·
IF 3.409
Jian Cao,Xiaoli Jin,Zhaoyu Ma,Huiqing Wang,Yixue Xu,Yuwei Guo,Haiquan Xie,Junying Zhang
Graphitic carbon nitride (g-C3N4) is gaining more and more attentions as a promising metal-free photocatalyst for H2 production. Nevertheless, from the perspective of practical applications, the photocatalytic performance over g-C3N4 in visible-light region needs a further improvement. In this work, C doping and C quantum dots (QDs) are co-integrated in g-C3N4 by a one-step thermal polymerization method to obtain an advanced C QDs/C doped g-C3N4 photocatalyst. The synergistic effects of C doping and C QDs modification promote the photocatalytic activity of g-C3N4 significantly. The optimal C QDs/C doped g-C3N4 exhibits a significant improvement on visible-light-driven photocatalytic hydrogen production (205 μmol g−1 h−1) with an apparent quantum yield (AQE) at 420 nm reaching 1.24%, which is approximately nine-fold enhancement than that of pristine g-C3N4. The increased photocatalytic activity mainly benefits from the enhanced visible light absorption and carrier separation efficiency. This study may open a new perspective for the design and fabrication of C-modified g-C3N4 for photocatalytic hydrogen production.
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JOURNAL OF HAZARDOUS MATERIALS
·
2022
·
IF 14.224
Jiabao Wu,Ying Tao,Chi Zhang,Qiong Zhu,Dieqing Zhang,Guisheng Li
Photoelectrochemical (PEC) activation of chloride ions (Cl - ) to degrade persistent organic pollutants (POPs) is a promising strategy for the treatment of industrial saline organic wastewater. However, the wide application of this technology is greatly restricted due to the general photoanode activation of Cl - with poor capability, the propensity to produce toxic by-products chlorates, and the narrow pH range. Herein, oxygen vacancies-enriched titanium dioxide (O v -TiO 2 ) photoanode is explored to strongly activate Cl - to drive the deep mineralization of POPs wastewater in a wide pH range (2−12) with simultaneous production of H 2 . More importantly, nearly no toxic by-product of chlorates was produced during such PEC-Cl system. The degradation efficiency of 4-CP and H 2 generation rate by O v -TiO 2 were 99.9% within 60 min and 198.2 μmol h −1 cm −2 , respectively, which are far superior to that on the TiO 2 (33.1% within 60 min, 27.5 μmol h −1 cm −2 ) working electrode. DFT calculation and capture experiments revealed that O v -TiO 2 with abundant oxygen vacancies is conducive to the activation of Cl - to produce more reactive chlorine species, evidenced by its high production of free chlorine (48.7 mg L −1 vs 7.5 mg L −1 of TiO 2 ). The as-designed PEC-Cl system in this work is expected to realize the purification of industrial saline organic wastewater coupling with green energy H 2 evolution.
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