In Situ-Grown Island-Shaped Hollow Graphene on TaON with Spatially Separated Active Sites Achieving Enhanced Visible-Light CO2 Reduction

ACS Catalysis ◽  
2020 ◽  
Vol 10 (24) ◽  
pp. 15083-15091
Author(s):  
Lang Pei ◽  
Yongjun Yuan ◽  
Wangfeng Bai ◽  
Taozhu Li ◽  
Heng Zhu ◽  
...  
Keyword(s):  
Visible Light ◽  
Active Sites ◽  
Co2 Reduction

scholarly journals In Situ Spectroscopic Methods for Electrocatalytic CO2 Reduction

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 481
Author(s):  
Lei Jin ◽  
Ali Seifitokaldani
Keyword(s):  
Energy Conversion ◽  
Conversion Efficiency ◽  
Active Sites ◽  
Co2 Reduction ◽  
Value Added ◽  
Energy Conversion Efficiency ◽  
High Energy ◽  
Spectroscopic Methods ◽  
X Ray

Electrochemical reduction of CO2 to value-added chemicals and fuels is a promising approach to store renewable energy while closing the anthropogenic carbon cycle. Despite significant advances in developing new electrocatalysts, this system still lacks enough energy conversion efficiency to become a viable technology for industrial applications. To develop an active and selective electrocatalyst and engineer the reaction environment to achieve high energy conversion efficiency, we need to improve our knowledge of the reaction mechanism and material structure under reaction conditions. In situ spectroscopies are among the most powerful tools which enable measurements of the system under real conditions. These methods provide information about reaction intermediates and possible reaction pathways, electrocatalyst structure and active sites, as well as the effect of the reaction environment on products distribution. This review aims to highlight the utilization of in situ spectroscopic methods that enhance our understanding of the CO2 reduction reaction. Infrared, Raman, X-ray absorption, X-ray photoelectron, and mass spectroscopies are discussed here. The critical challenges associated with current state-of-the-art systems are identified and insights on emerging prospects are discussed.

scholarly journals Active sites for tandem reactions of CO2 reduction and ethane dehydrogenation

2018 ◽  
Vol 115 (33) ◽  
pp. 8278-8283 ◽  
Author(s):  
Binhang Yan ◽  
Siyu Yao ◽  
Shyam Kattel ◽  
Qiyuan Wu ◽  
Zhenhua Xie ◽  
...  
Keyword(s):  
Active Sites ◽  
Density Functional ◽  
Raw Materials ◽  
Co2 Reduction ◽  
Tandem Reactions ◽  
In Situ Characterization ◽  
Functional Theory ◽  
Ethane Dehydrogenation ◽  
Ethylene Selectivity

Ethylene (C2H4) is one of the most important raw materials for chemical industry. The tandem reactions of CO2-assisted dehydrogenation of ethane (C2H6) to ethylene creates an opportunity to effectively use the underutilized ethane from shale gas while mitigating anthropogenic CO2 emissions. Here we identify the most likely active sites over CeO2-supported NiFe catalysts by using combined in situ characterization with density-functional theory (DFT) calculations. The experimental and theoretical results reveal that the Ni–FeOx interfacial sites can selectively break the C–H bonds and preserve the C–C bond of C2H6 to produce ethylene, while the Ni–CeOx interfacial sites efficiently cleave all of the C–H and C–C bonds to produce synthesis gas. Controlled synthesis of the two distinct active sites enables rational enhancement of the ethylene selectivity for the CO2-assisted dehydrogenation of ethane.

Facile in situ fabrication of Cu2O@Cu metal-semiconductor heterostructured nanorods for efficient visible-light driven CO2 reduction

2020 ◽  
Vol 385 ◽  
pp. 123940 ◽  
Author(s):  
Jianqing Zhou ◽  
Yifei Li ◽  
Luo Yu ◽  
Zhengpeng Li ◽  
Danfeng Xie ◽  
...  
Keyword(s):  
Visible Light ◽  
Co2 Reduction ◽  
In Situ Fabrication ◽  
Visible Light Driven

scholarly journals Charge-Transfer Regulated Visible Light Driven Photocatalytic H2 Production and CO2 Reduction in Tetrathiafulvalene Based Coordination Polymer Gel

2020 ◽  
Author(s):  
Parul Verma ◽  
Pallavi Sarkar ◽  
Ashish Singh ◽  
Swapan Pati ◽  
Tapas Maji
Keyword(s):  
Photocatalytic Activity ◽  
Charge Transfer ◽  
Coordination Polymer ◽  
Visible Light ◽  
Co2 Reduction ◽  
Pt Nanoparticles ◽  
H2 Production ◽  
Polymer Gel ◽  
H2 Evolution

Abstract The much-needed renewable alternatives to fossil fuel can be achieved efficiently and sustainably by converting solar energy to solar fuels via hydrogen generation from water or CO2 reduction. In this regard, a soft processable metal-organic hybrid semiconducting material has been developed and studied for photocatalytic activity towards H2 production and CO2 reduction to CO and CH4 under visible light and direct sunlight irradiation. A tetrapodal low molecular weight gelator is synthesized by integrating tetrathiafulvalene and terpyridine through amide linkage (TPY-TTF). The TPY-TTF acts as a linker and by self-assembly with ZnII results in a charge-transfer (CT) coordination polymer gel (CPG); Zn-TPY-TTF. The Zn-TPY-TTF shows impressive photocatalytic activity towards H2 production (rate = 530 μmol g-1h-1) and CO2 reduction to CO (rate = 438 μmol g-1h-1, selectivity >99%) regulated by charge-transfer interaction. Furthermore, in-situ stabilization of Pt nanoparticles to CPG (Pt@Zn-TPY-TTF) exhibits remarkably enhanced H2 evolution (rate =14727 μmol g-1h-1). Importantly, Pt@Zn-TPY-TTF modulate the CO2 reduction from CO to CH4 (rate = 292 μmol g-1h-1, selectivity >97%). Real-time CO2 reduction reaction is monitored by in-situ DRIFT study and subsequent plausible mechanism is derived computationally. The photocatalytic activity of Zn-TPY-TTF and Pt@Zn-TPY-TTF composite was also examined under sunlight that display excellent H2 evolution and CO2 reduction.

scholarly journals Charge-transfer regulated visible light driven photocatalytic H2 production and CO2 reduction in tetrathiafulvalene based coordination polymer gel

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Parul Verma ◽  
Ashish Singh ◽  
Faruk Ahamed Rahimi ◽  
Pallavi Sarkar ◽  
Sukhendu Nath ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Charge Transfer ◽  
Coordination Polymer ◽  
Visible Light ◽  
Self Assembly ◽  
Hydrogen Generation ◽  
Co2 Reduction ◽  
Pt Nanoparticles ◽  
Polymer Gel

AbstractThe much-needed renewable alternatives to fossil fuel can be achieved efficiently and sustainably by converting solar energy to fuels via hydrogen generation from water or CO2 reduction. Herein, a soft processable metal-organic hybrid material is developed and studied for photocatalytic activity towards H2 production and CO2 reduction to CO and CH4 under visible light as well as direct sunlight irradiation. A tetrapodal low molecular weight gelator (LMWG) is synthesized by integrating tetrathiafulvalene (TTF) and terpyridine (TPY) derivatives through amide linkages and results in TPY-TTF LMWG. The TPY-TTF LMWG acts as a linker, and self-assembly of this gelator molecules with ZnII ions results in a coordination polymer gel (CPG); Zn-TPY-TTF. The Zn-TPY-TTF CPG shows high photocatalytic activity towards H2 production (530 μmol g−1h−1) and CO2 reduction to CO (438 μmol g−1h−1, selectivity > 99%) regulated by charge-transfer interactions. Furthermore, in situ stabilization of Pt nanoparticles on CPG (Pt@Zn-TPY-TTF) enhances H2 evolution (14727 μmol g−1h−1). Importantly, Pt@Zn-TPY-TTF CPG produces CH4 (292 μmol g−1h−1, selectivity > 97%) as CO2 reduction product instead of CO. The real-time CO2 reduction reaction is monitored by in situ DRIFT study, and the plausible mechanism is derived computationally.

scholarly journals Investigation of the Kinetics and Reaction Mechanism for Photodegradation Tetracycline Antibiotics over Sulfur-Doped Bi2WO6-x/ZnIn2S4 Direct Z-Scheme Heterojunction

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2123
Author(s):  
Yanbo Jiang ◽  
Kai Huang ◽  
Wei Ling ◽  
Xiandong Wei ◽  
Yijing Wang ◽  
...  
Keyword(s):  
Visible Light ◽  
Environmental Remediation ◽  
Active Sites ◽  
Rational Design ◽  
Organic Pollutant ◽  
Xps Spectra ◽  
Interfacial Transport ◽  
Photodegradation Rate ◽  
Photochemical Properties

The rational design of direct Z-scheme heterostructural photocatalysts using solar energy is promising for energy conversion and environmental remediation, which depends on the precise regulation of redox active sites, rapid spatial separation and transport of photoexcited charge and a broad visible light response. The Bi2WO6 materials have been paid more and more attention because of their unique photochemical properties. In this study, S2− doped Bi2WO6-x coupled with twin crystal ZnIn2S4 nanosheets (Sov−BWO/T−ZIS) were prepared as an efficient photocatalyst by a simple hydrothermal method for the removal of tetracycline hydrochloride (TCH). Multiple methods (XRD, TEM, XPS, EPR, UV vis DRS, PL etc.) were employed to systematically investigate the morphology, structure, composition and photochemical properties of the as-prepared samples. The XRD spectrum indicated that the S2− ions were successfully doped into the Sov−BWO component. XPS spectra and photoelectrochemical analysis proved that S2− served as electronic bridge and promoted captured electrons of surface oxygen vacancies transfer to the valence band of T−ZIS. Through both experimental and in situ electron paramagnetic resonance (in situ EPR) characterizations, a defined direct Z-scheme heterojunction in S-BWO/T−ZIS was confirmed. The improved photocatalytic capability of S-BWO/T−ZIS results ascribed that broadened wavelength range of light absorption, rapid separation and interfacial transport of photoexcited charge, precisely regulated redox centers by optimizing the interfacial transport mode. Particularly, the Sov−50BWO/T−ZIS Z-scheme heterojunction exhibited the highest photodegradation rate was 95% under visible light irradiation. Moreover, this heterojunction exhibited a robust adsorption and degradation capacity, providing a promising photocatalyst for an organic pollutant synergistic removal strategy.

Fabrication of hierarchical Co3O4@CdIn2S4 p–n heterojunction photocatalysts for improved CO2 reduction with visible light

2020 ◽  
Vol 8 (15) ◽  
pp. 7177-7183 ◽  
Author(s):  
Lijuan Huang ◽  
Bifang Li ◽  
Bo Su ◽  
Zhuang Xiong ◽  
Chunjie Zhang ◽  
...  
Keyword(s):  
Visible Light ◽  
Co2 Reduction ◽  
Surface Growth ◽  
Growth Method

Hierarchical Co3O4@CdIn2S4 p–n heterojunction photocatalysts have been constructed by an in situ surface growth method for CO2 reduction with visible light.

In situ fabrication of Ag3PO4/TiO2 nanotube heterojunctions with enhanced visible-light photocatalytic activity

2015 ◽  
Vol 17 (18) ◽  
pp. 12199-12206 ◽  
Author(s):  
Zhen Wei Tong ◽  
Dong Yang ◽  
Yuan Yuan Sun ◽  
Yao Tian ◽  
Zhong Yi Jiang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Active Sites ◽  
Dye Adsorption ◽  
Adsorption Properties ◽  
Visible Light Photocatalytic Activity ◽  
In Situ Fabrication ◽  
Growth Method ◽  
Visible Light Photocatalytic

Ag3PO4/TNT heterojunctions have been fabricated via a facile in situ growth method. Compared with pure Ag3PO4, Ag3PO4/TNT possesses more active sites, less bulk defects, as well as better dye adsorption properties, and thus exhibits a significantly elevated photocatalytic activity and stability for RhB degradation.

scholarly journals Stable, active CO2 reduction to formate via redox-modulated stabilization of active sites

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Le Li ◽  
Adnan Ozden ◽  
Shuyi Guo ◽  
F. Pelayo Garcı́a de Arquer ◽  
Chuanhao Wang ◽  
...  
Keyword(s):  
Active Sites ◽  
Structural Changes ◽  
Experimental Studies ◽  
Co2 Reduction ◽  
Membrane Electrode Assembly ◽  
Membrane Electrode ◽  
Faradaic Efficiency ◽  
Stable Production ◽  
Exchange Membrane

AbstractElectrochemical reduction of CO2 (CO2R) to formic acid upgrades waste CO2; however, up to now, chemical and structural changes to the electrocatalyst have often led to the deterioration of performance over time. Here, we find that alloying p-block elements with differing electronegativities modulates the redox potential of active sites and stabilizes them throughout extended CO2R operation. Active Sn-Bi/SnO2 surfaces formed in situ on homogeneously alloyed Bi0.1Sn crystals stabilize the CO2R-to-formate pathway over 2400 h (100 days) of continuous operation at a current density of 100 mA cm−2. This performance is accompanied by a Faradaic efficiency of 95% and an overpotential of ~ −0.65 V. Operating experimental studies as well as computational investigations show that the stabilized active sites offer near-optimal binding energy to the key formate intermediate *OCHO. Using a cation-exchange membrane electrode assembly device, we demonstrate the stable production of concentrated HCOO– solution (3.4 molar, 15 wt%) over 100 h.

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