scholarly journals Single-Atom Pd–N3 Sites on Carbon-Deficient g-C3N4 for Photocatalytic H2 Evolution

2021 ◽  
Author(s):  
Guimei Liu ◽  
Haiqin Lv ◽  
Yubin Zeng ◽  
Mingzhe Yuan ◽  
Qingguo Meng ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Active Sites ◽  
Charge Carriers ◽  
Single Atom ◽  
H2 Evolution ◽  
Environment Friendly ◽  
Coordination Environment ◽  
Highly Active ◽  
Excellent Photocatalytic Activity ◽  
New Strategy

AbstractPhotocatalytic hydrogen evolution is an attractive field for future environment-friendly energy. However, fast recombination of photogenerated charges severely inhibits hydrogen efficiency. Single-atom cocatalysts such as Pt have emerged as an effective method to enhance the photocatalytic activity by introduction of active sites and boosting charge separation with low-coordination environment. Herein, we demonstrated a new strategy to develop a highly active Pd single atom in carbon-deficient g-C3N4 with a unique coordination. The single-atom Pd–N3 sites constructed by oil bath heating and photoreduction process were confirmed by HADDF-STEM and XPS measurements. Introduction of single-atom Pd greatly improved the separation and transportation of charge carriers, leading to a longer lifespan for consequent reactions. The obtained single-atom Pd loaded on the carbon-deficient g–C3N4 showed excellent photocatalytic activity in hydrogen production with about 24 and 4 times higher activity than that of g–C3N4 and nano-sized Pd on the same support, respectively. This work provides a new insight on the design of single-atom catalyst.

scholarly journals Secondary-Atom-Doping Enables Robust Fe–N–C Single-Atom Catalysts with Enhanced Oxygen Reduction Reaction

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Xin Luo ◽  
Xiaoqian Wei ◽  
Hengjia Wang ◽  
Wenling Gu ◽  
Takuma Kaneko ◽  
...  
Keyword(s):  
Active Sites ◽  
Reduction Reaction ◽  
Single Atom ◽  
General Strategy ◽  
Carbon Supports ◽  
Coordination Environment ◽  
Energy Devices ◽  
Highly Active ◽  
Half Wave ◽  
Secondary Doping

AbstractSingle-atom catalysts (SACs) with nitrogen-coordinated nonprecious metal sites have exhibited inimitable advantages in electrocatalysis. However, a large room for improving their activity and durability remains. Herein, we construct atomically dispersed Fe sites in N-doped carbon supports by secondary-atom-doped strategy. Upon the secondary doping, the density and coordination environment of active sites can be efficiently tuned, enabling the simultaneous improvement in the number and reactivity of the active site. Besides, structure optimizations in terms of the enlarged surface area and improved hydrophilicity can be achieved simultaneously. Due to the beneficial microstructure and abundant highly active FeN5 moieties resulting from the secondary doping, the resultant catalyst exhibits an admirable half-wave potential of 0.81 V versus 0.83 V for Pt/C and much better stability than Pt/C in acidic media. This work would offer a general strategy for the design and preparation of highly active SACs for electrochemical energy devices.

The Synthesis of CuS Hexagonal Nanosheet-Graphene for Use as a High Performance Photocatalyst

NANO ◽  
2016 ◽  
Vol 11 (05) ◽  
pp. 1650054 ◽  
Author(s):  
Bin Zeng ◽  
Yang Yin
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
High Performance ◽  
Organic Pollutant ◽  
High Photocatalytic Activity ◽  
Charge Carriers ◽  
Thermal Method ◽  
One Pot ◽  
Graphene Nanocomposites ◽  
Excellent Photocatalytic Activity

CuS hexagonal nanosheet/graphene was fabricated by a facile one-pot microwave-thermal method. The samples possess excellent photocatalytic activity for degradation of organic pollutant under visible light. The high photocatalytic activity was attributed to the deposition of CuS hexagonal nanosheet onto graphene. CuS nanosheet serves as a transporter which efficiently inhibits the recombination of the photo-induced charge carriers in the nanocomposites. The developed method demonstrates a facile approach towards the synthesis of two-dimensional semiconductor-graphene nanocomposites with excellent photocatalytic performance under visible light.

ZnS/HALLOYSITE NANOCOMPOSITES: SYNTHESIS, CHARACTERIZATION AND ENHANCED PHOTOCATALYTIC ACTIVITY

2013 ◽  
Vol 06 (02) ◽  
pp. 1350013 ◽  
Author(s):  
YI ZHANG ◽  
HUAMING YANG
Keyword(s):  
Photocatalytic Activity ◽  
Active Sites ◽  
Uv Light ◽  
Halloysite Nanotubes ◽  
Narrow Particle Size Distribution ◽  
Zns Nanoparticles ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Eosin B ◽  
Excellent Photocatalytic Activity

Zinc sulfide (ZnS) nanoparticles are successfully deposited on the surface of natural halloysite nanotubes (HNTs) to produce ZnS /HNTs nanocomposites. The samples are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy and photoluminescence (PL) analysis. The results indicate that ZnS nanoparticles are uniformly attached on the surface of HNTs with narrow particle size distribution center at ~10 nm, and are prevented from aggregation by HNTs and expose more active sites. ZnS /HNTs show excellent photocatalytic activity for the degradation of eosin B under UV light, better than pure ZnS and HNTs, indicating its potential application in the field of environmental protection. The mechanism for photocatalytic activity enhancement is also investigated.

scholarly journals CuInS2/Mg(OH)2 Nanosheets for the Enhanced Visible-Light Photocatalytic Degradation of Tetracycline

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1567 ◽  
Author(s):  
Xiaogang Zheng ◽  
Yiting Mao ◽  
Jing Wen ◽  
Xiaojin Fu ◽  
Xinhui Liu
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Ph Value ◽  
Inorganic Ions ◽  
Charge Carriers ◽  
Oh Radicals ◽  
Cycle Times ◽  
Atomic Force ◽  
Excellent Photocatalytic Activity ◽  
Visible Light Driven

CuInS2/Mg(OH)2 (CIS/Mg(OH)2) nanosheets have been prepared for the visible light activated photodegradation of tetracycline hydrochloride (TCH). The introduction of CuInS2 has proven to enhance the photocatalytic activity of Mg(OH)2 nanosheets. It’s ascribed to the enhanced transfer and separation of charge carriers at the junction interface between CuInS2 and Mg(OH)2. The photocatalytic activity of obtained CIS/Mg(OH)2 is greatly affected by CuInS2 content, pH value, and inorganic ions. Among these samples, 2-CIS/Mg(OH)2 exhibits the excellent photocatalytic activity and durability for the visible light driven removal of TCH after five cycle times. Atomic force microscope (AFM) images indicate that the surface roughness of 2-CIS/Mg(OH)2 is intensively influenced in adsorption-photocatalysis process. The •O2− and •OH radicals are vital for the visible light driven photocatalytic activity of 2-CIS/Mg(OH)2 for TCH removal.

scholarly journals Synthesis and enhanced photocatalytic performance of 0D/2D CuO/tourmaline composite photocatalysts

2020 ◽  
Vol 11 ◽  
pp. 407-416 ◽  
Author(s):  
Changqiang Yu ◽  
Min Wen ◽  
Zhen Tong ◽  
Shuhua Li ◽  
Yanhong Yin ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Organic Contaminants ◽  
Hydrothermal Process ◽  
Charge Carriers ◽  
Molecular Vibration ◽  
Surface Element ◽  
Composite Photocatalysts ◽  
Excellent Photocatalytic Activity ◽  
Photoinduced Charge ◽  
Facile Hydrothermal Process

Photocatalysis is considered to be a green and promising technology for transforming organic contaminants into nontoxic products. In this work, a CuO/tourmaline composite with zero-dimensional/two-dimensional (0D/2D) CuO architecture was successfully obtained via a facile hydrothermal process, and its photocatalytic activity was evaluated by the degradation of methylene blue (MB). Surface element valence state and molecular vibration characterization revealed that CuO chemically interacted with tourmaline via Si–O–Cu bonds. The specific surface area of the CuO/tourmaline composite (23.60 m2 g−1) was larger than that of the pristine CuO sample (3.41 m2 g−1). The CuO/tourmaline composite exhibited excellent photocatalytic activity for the degradation of MB, which was ascribed to the increase in the quantity of the adsorption-photoreactive sites and the efficient utilization of the photoinduced charge carriers. This study provides a facile strategy for the construction of 0D/2D CuO structures and the design of tourmaline-based functional composite photocatalysts for the treatment of organic contaminants in water.

scholarly journals Influence of Hydrogenation on Morphology, Chemical Structure and Photocatalytic Efficiency of Graphitic Carbon Nitride

2021 ◽  
Vol 22 (23) ◽  
pp. 13096
Author(s):  
Daria Baranowska ◽  
Tomasz Kędzierski ◽  
Małgorzata Aleksandrzak ◽  
Ewa Mijowska ◽  
Beata Zielińska
Keyword(s):  
Photocatalytic Activity ◽  
Active Sites ◽  
Chemical Structure ◽  
Carbon Nitride ◽  
Elevated Temperatures ◽  
Hydrogen Atmosphere ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Photocatalytic Efficiency ◽  
Highly Active

In this contribution, the effect of hydrogenation conditions atmosphere (temperature and time) on physicochemical properties and photocatalytic efficiency of graphitic carbon nitride (g-C3N4, gCN) was studied in great details. The changes in the morphology, chemical structure, optical and electrochemical properties were carefully investigated. Interestingly, the as-modified samples exhibited boosted photocatalytic degradation of Rhodamine B (RhB) with the assistance of visible light irradiation. Among modified gCN, the sample annealed at 500 °C for 4 h (500-4) in H2 atmosphere exhibited the highest photocatalytic activity—1.76 times higher compared to pristine gCN. Additionally, this sample presented high stability and durability after four cycles. It was noticed that treating gCN with hydrogen at elevated temperatures caused the creation of nitrogen vacancies on gCN surfaces acting as highly active sites enhancing the specific surface area and improving the mobility of photogenerated charge carriers leading to accelerating the photocatalytic activity. Therefore, it is believed that detailed optimization of thermal treatment in a hydrogen atmosphere is a facile approach to boost the photoactivity of gCN.

scholarly journals Synthesis, Characterization, and Photocatalytic Activity of g-C3N4/GaN-ZnO Composite

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Nguyen Ha Trang ◽  
Tran Thi Viet Ha ◽  
Nguyen Minh Viet ◽  
Nguyen Minh Phuong
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Recombination Rate ◽  
Active Sites ◽  
High Stability ◽  
Low Cost ◽  
Charge Carriers ◽  
Strong Reduction ◽  
Ft Ir ◽  
Antibiotic Residue

Recently, photocatalysis process has shown great potential as a low-cost, environmentally friendly, and sustainable method for the water/wastewater treatment. Among that, g-C3N4 is one of the most promising photocatalyst and widely used for a variety of applications. In spite of some unique features such as strong reduction ability, active under visible light, nontoxic, and high stability, g-C3N4 photocatalytic capability under visible light is limited due to fast recombination rate of reactive charges. To deal with this issue, in this study, g-C3N4 is combined with GaN-ZnO for reducing the recombination rate of charge carriers and increasing the active sites. The g-C3N4/GaN-ZnO composite was characterized by several methods such as SEM, EDX, XRD, FT-IR, UV-Vis, and BET. It is also observed that the composite with outstanding features can work effectively under visible light; thus, it is likely to be widely applied in environment treatment, especially in antibiotic residue with more than 90% of tetracycline was decomposed after 3 hours.

scholarly journals A Cobalt-Iron Double-Atom Catalyst for the Oxygen Evolution Reaction

2019 ◽  
Author(s):  
Lichen Bai ◽  
Chia-Shuo Hsu ◽  
Duncan Alexander ◽  
Hao Ming Chen ◽  
Xile Hu
Keyword(s):  
Oxygen Evolution ◽  
Active Site ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
Single Atom ◽  
X Ray ◽  
Highly Active ◽  
Cobalt Iron ◽  
X Ray Absorption

Single atom catalysts exhibit well-defined active sites and potentially maximum atomic efficiency. However, they are unsuitable for reactions that benefit from bimetallic promotion such as the oxygen evolution reaction (OER) in alkaline medium. Here we show that a single atom Co precatalyst can be in-situ transformed into a Co-Fe double atom catalyst for OER. This catalyst exhibits one of the highest turnover frequencies among metal oxides. Electrochemical, microscopic, and spectroscopic data including those from operando X-ray absorption spectroscopy, reveal a dimeric Co-Fe moiety as the active site of the catalyst. This work demonstrates double-atom catalysis as a promising approach for the developed of defined and highly active OER catalysts.

Highly active dye-sensitized photocatalytic H2 evolution catalyzed by a single-atom Pt cocatalyst anchored onto g-C3N4 nanosheets under long-wavelength visible light irradiation

2018 ◽  
Vol 42 (17) ◽  
pp. 14083-14086 ◽  
Author(s):  
Yuan Xue ◽  
Yonggang Lei ◽  
Xiangyu Liu ◽  
Yanan Li ◽  
Wanan Deng ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Single Atom ◽  
Eosin Y ◽  
H2 Evolution ◽  
Long Wavelength ◽  
Dye Sensitized ◽  
Highly Active ◽  
Photocatalytic H2 Evolution

A single-atom Pt cocatalyst anchored onto g-C3N4 nanosheets could efficiently catalyze H2 evolution from an Eosin Y-sensitized system under 520 nm irradiation.

Fabrication of N-doped Reduced Graphene Oxide/Ag3PO4 Nanocomposite with Excellent Photocatalytic Activity for the Degradation of Organic Pollutants

NANO ◽  
2017 ◽  
Vol 12 (01) ◽  
pp. 1750013 ◽  
Author(s):  
Longhai Feng ◽  
Lirong Kong ◽  
Zhenyuan Ji ◽  
Yi Wang ◽  
Xiaoping Shen ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photocatalytic Performance ◽  
Organic Pollutant ◽  
Charge Carriers ◽  
Simulated Solar Light ◽  
Solar Light Irradiation ◽  
Reduced Graphene ◽  
Excellent Photocatalytic Activity

An efficient N-doped reduced graphene oxide (N-RGO)/Ag3PO4 nanocomposite with enhanced photocatalytic activity has been prepared through a facile solution-based approach. Since N-RGO could offer more sites for the anchoring of Ag3PO4 nanoparticles, and effectively promote the charge carriers separation and transfer due to its high electrical conductivity, the photocatalytic activity of N-RGO/Ag3PO4 nanocomposite is much higher than bare Ag3PO4 and N-RGO in the degradation of phenol pollutant under simulated solar light irradiation. The mechanism for the photocatalytic process was also investigated. The excellent photocatalytic performance makes the N-RGO/Ag3PO4 nanocomposite a promising photocatalyst for organic pollutant treatment.

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