Selective photocatalytic CO2 reduction on copper–titanium dioxide: a study of the relationship between CO production and H2 suppression

2019 ◽  
Vol 55 (56) ◽  
pp. 8068-8071 ◽  
Author(s):  
Yangchun Lan ◽  
Yongzhi Xie ◽  
Jiaxi Chen ◽  
Zhuofeng Hu ◽  
Dehu Cui

High selectivity of CO2 reduction and suppression of H2 evolution on a Cu/TiO2 photocatalyst.

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1115
Author(s):  
Lujia Ding ◽  
Qiutong Han ◽  
Hong Lu ◽  
Yong Yang ◽  
Gang Lu ◽  
...  

Atomic valence state regulation is an advantageous approach for improving photocatalytic efficiency and product selectivity. However, it is difficult to precisely control the ratio of the different valence states on the surface and the relationship between the surface valence change and catalytic efficiency in the photocatalytic reaction process is unclear. Herein, CeVO4 ultrathin nanosheets were fabricated by one-step solvothermal method with ethanolamine (MEA) as the structure-directing agent. The ratio of the concentrations of intrinsic Ce4+ and Ce3+ ions is precisely modulated from 19.82:100 to 13.33:100 changed by the volume of MEA added without morphology modification. The photocatalytic efficiency increases as the concentrations of intrinsic Ce4+ and Ce3+ ions decrease and CV3 (prepared with 3 mL of MEA) shows the highest CO generation rate approximately 6 and 14 times larger than CV (prepared without MEA) and CV1 (prepared with 1 mL of MEA), respectively, in the photocatalytic CO2 reduction. Interestingly, about 6.8% photo-induced Ce4+ ions were generated on the surface of the catalysts during the photocatalytic CO2 reduction without any phase and morphology changes for CV3. The photocatalytic reaction mechanism is proposed considering the intrinsic and photo-induced Ce4+ ions to obtain efficient photocatalysts.


Author(s):  
Qing Huang ◽  
Jiang Liu ◽  
Liang Feng ◽  
Qi Wang ◽  
Wei Guan ◽  
...  

Abstract Photocatalytic CO2 reduction into energy carriers is of utmost importance due to the rising concentrations of carbon dioxide and the depleting energy resource. However, the highly selective generation of desirable hydrocarbon fuel, such as methane (CH4), from CO2 remains extremely challenging. Herein, we present two stable polyoxometalate-grafted metalloporphyrin coordination frameworks (POMCFs), which are constructed with reductive Zn-ε-Keggin clusters and photosensitive TCPP linkers, exhibiting high selectivity (> 96%) for CH4 formation in photocatalytic CO2 reduction system. To our knowledge, the high CH4 selectivity of POMCFs has surpassed all of the reported coordiantion framework-based heterogeneous photocatalysts for CO2-to-CH4 conversion. Significantly, the introduction of Zn-ε-keggin cluster with strong reducing ability is the important origin for POMCFs to obtain high photocatalytic selectivity for CH4 formation, considering that eight MoV atoms can theoretically donate eight electrons to fulfill the multi-electrons reduction process of CO2 to CH4 transformation.


2014 ◽  
Vol 1040 ◽  
pp. 183-187 ◽  
Author(s):  
Ilia A. Lysak ◽  
Galina V. Lysak ◽  
Tatyana D. Malinovskaya ◽  
Anatoly S. Ruhov

In the current article the use of nanoparticles of titanium dioxide is justified to be an active component of the photocatalytic materials. The relationship between composition, structure and bactericidal properties of titanium dioxide is also established. It is shown that the polypropylene carrier comprising on a surface of at least 2.1 ± 0.3 mg/g of titanium dioxide nanoparticles, where both phases of titanium dioxide such as rutile and anatase are presented, allows the antibacterial treatment of water with high efficiency and it can be used for water purification from microbial contamination.


2008 ◽  
Vol 39-40 ◽  
pp. 399-401
Author(s):  
Viliam Pavlík ◽  
Eugen Jóna ◽  
Martina Sapietová ◽  
Soňa Šnircová

The glasses with composition of Li2O . 2 SiO2 . n ZrO2 . n TiO2 (where n = 0; 0.015; 0.031; 0.050; 0.075; 0.1; 0.15; 0.2) were prepared and the relationship between structural and selected parameters of thermal stability vs. crystallization has been studied by differential thermal analysis. Structural analysis was provided by X–ray diffraction. The order of thermal stability vs. crystallization representing of activation energy of studied glass systems which increase with higher addition both oxides. The same order was obtained from the values of XRD. On the comparison the glasses with zero addition titanium dioxide their activation energy was much higher.


2016 ◽  
Vol 52 (50) ◽  
pp. 7886-7889 ◽  
Author(s):  
Kanemichi Muraoka ◽  
Hiromu Kumagai ◽  
Miharu Eguchi ◽  
Osamu Ishitani ◽  
Kazuhiko Maeda

A hybrid photocatalyst composed of an yttrium–tantalum oxynitride (with a 2.1 eV band gap) and a binuclear Ru(ii) complex containing both photosensitizing and catalytic units was capable of reducing CO2 to HCOOH with very high selectivity (>99%) under visible light (>400 nm) irradiation.


2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Paulina Półrolniczak ◽  
Mariusz Walkowiak

AbstractTiOThe relationship between reaction conditions and morphology is discussed and practical guidelines for titanium dioxide nanowire synthesis are suggested


2021 ◽  
Author(s):  
Rongming Cai ◽  
Mingzi Sun ◽  
Jiazheng Ren ◽  
Min Ju ◽  
Xia Long ◽  
...  

Copper-based catalysts are efficient for CO2 reduction affording commodity chemicals. However, the Cu(I) active species are easily reduced to Cu(0) during CO2RR, leading to rapid decay of catalytic performance. Herein,...


RSC Advances ◽  
2018 ◽  
Vol 8 (17) ◽  
pp. 9112-9119 ◽  
Author(s):  
Avraham Dayan ◽  
Gideon Fleminger ◽  
Osnat Ashur-Fabian

This work presents a UVA switchable integrin-targeted photodynamic therapy in melanoma, composed of an RGD-modified DLDH conjugated to TiO2nanoparticles, with high selectivity towards integrin-expressing cancer cells.


2018 ◽  
Vol 115 (50) ◽  
pp. 12686-12691 ◽  
Author(s):  
Bianca M. Ceballos ◽  
Jenny Y. Yang

A critical challenge in electrocatalytic CO2 reduction to renewable fuels is product selectivity. Desirable products of CO2 reduction require proton equivalents, but key catalytic intermediates can also be competent for direct proton reduction to H2. Understanding how to manage divergent reaction pathways at these shared intermediates is essential to achieving high selectivity. Both proton reduction to hydrogen and CO2 reduction to formate generally proceed through a metal hydride intermediate. We apply thermodynamic relationships that describe the reactivity of metal hydrides with H+ and CO2 to generate a thermodynamic product diagram, which outlines the free energy of product formation as a function of proton activity and hydricity (∆GH−), or hydride donor strength. The diagram outlines a region of metal hydricity and proton activity in which CO2 reduction is favorable and H+ reduction is suppressed. We apply our diagram to inform our selection of [Pt(dmpe)2](PF6)2 as a potential catalyst, because the corresponding hydride [HPt(dmpe)2]+ has the correct hydricity to access the region where selective CO2 reduction is possible. We validate our choice experimentally; [Pt(dmpe)2](PF6)2 is a highly selective electrocatalyst for CO2 reduction to formate (>90% Faradaic efficiency) at an overpotential of less than 100 mV in acetonitrile with no evidence of catalyst degradation after electrolysis. Our report of a selective catalyst for CO2 reduction illustrates how our thermodynamic diagrams can guide selective and efficient catalyst discovery.


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