Modulation of photo-generated solvated electrons for ammonia synthesis via facet-dependent engineering of heterojunctions

To mitigate global problems related to energy and global warming, it is helpful to develop an ammonia synthesis process using catalysts that are highly active under mild conditions. Here we show that the ammonia synthesis activity of Ru/Ba/LaCeOx pre-reduced at 700 °C is the highest reported among oxide-supported Ru catalysts. Our results indicate that low crystalline oxygen-deficient composite oxides, which include Ba2+, Ce3+ and La3+, with strong electron-donating ability, accumulate on Ru particles and thus promote N≡N bond cleavage, which is the rate determining step for ammonia synthesis.

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Electron Donation by Low-Crystalline Ba-La-Ce Oxygen-Deficient Composite Oxide Accumulating on Ru Nanoparticles for Ammonia Synthesis under Mild Conditions

10.26434/chemrxiv.7763657 ◽

2019 ◽

Author(s):

Katsutoshi Sato ◽

Shin-ichiro Miyahara ◽

Yuta Ogura ◽

Kotoko Tsujimaru ◽

Yuichiro Wada ◽

...

Keyword(s):

Ammonia Synthesis ◽

Bond Cleavage ◽

Synthesis Process ◽

Strong Electron ◽

Mild Conditions ◽

Ru Nanoparticles ◽

Rate Determining Step ◽

Highly Active ◽

Composite Oxides ◽

Low Crystalline

To mitigate global problems related to energy and global warming, it is helpful to develop an ammonia synthesis process using catalysts that are highly active under mild conditions. Here we show that the ammonia synthesis activity of Ru/Ba/LaCeOx pre-reduced at 700 °C is the highest reported among oxide-supported Ru catalysts. Our results indicate that low crystalline oxygen-deficient composite oxides, which include Ba2+, Ce3+ and La3+, with strong electron-donating ability, accumulate on Ru particles and thus promote N≡N bond cleavage, which is the rate determining step for ammonia synthesis.

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Effect of Hydrothermal Treatment of Activated Carbon by Nitric Acid on Activ-ity of Ba-Ru-K/AC Catalyst for Ammonia Synthesis

CHINESE JOURNAL OF CATALYSIS (CHINESE VERSION) ◽

10.3724/sp.j.1088.2012.20233 ◽

2013 ◽

Vol 33 (7) ◽

pp. 1191-1197

Author(s):

Guoquan FENG ◽

Guojun LAN ◽

Ying LI ◽

Wenfeng HAN ◽

Huazhang LIU

Keyword(s):

Activated Carbon ◽

Nitric Acid ◽

Hydrothermal Treatment ◽

Ammonia Synthesis

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Photoredox Reactions of Iodo Iron(III) Complexes Containing Tetradentate Ligands

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20010109 ◽

2001 ◽

Vol 66 (1) ◽

pp. 109-118 ◽

Cited By ~ 4

Author(s):

Jozef Šima ◽

Dáša Lauková ◽

Vlasta Brezová

Keyword(s):

Schiff Bases ◽

Spin Trapping ◽

Molar Ratio ◽

Oh Radicals ◽

Solvated Electrons ◽

Open Chain ◽

Tetradentate Ligands ◽

Visible Irradiation ◽

Epr Spin Trapping ◽

Spin Trapping Technique

Photoredox reactions occurring in irradiated methanolic solutions of trans-[FeIII(R,R'-salen)(CH3OH)I], where R,R'-salen2- are N,N'-ethylenebis(R,R'-salicylideneiminato), tetradentate open-chain N2O2-Schiff bases with R,R' = H, 5-Cl, 5-Br, 3,5-di-Br, 3,5-di-(CH3), 3-OCH3, 5-OCH3, have been investigated and their mechanism proposed. The complexes are redox-stable in the dark. Ultraviolet and/or visible irradiation of methanolic solution of the complexes induces photoreduction of Fe(III) to Fe(II). Depending on the composition of the irradiated solutions, •CH2OH radicals or solvated electrons were identified by the EPR spin trapping technique. The final product of the photooxidation coupled with the photoreduction of Fe(III) is formaldehyde and the molar ratio of Fe(II) and CH2O is close to 2 : 1. The efficiency of the photoredox process is strongly wavelength-dependent and influenced by the peripheral groups R,R' of the tetradentate ligands.

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