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Updated: Apr 16, 2026

The Effect of Interfacial Chemical Bonding in TiO2-SiO2 Composites on Their Photocatalytic NOx Abatement Performance
Published on: July 4, 2017
Nitric oxide reduction to ammonia by TiO₂ electrons in colloid solution via consecutive one-electron transfer steps
Sara Goldstein1, David Behar1, Tijana Rajh2
1†Institute of Chemistry and the Accelerator Laboratory, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Abstract:
The reaction mechanism of nitric oxide (NO) reduction by excess electrons on TiO2 nanoparticles (e(TiO2)(-)) has been studied under anaerobic conditions. TiO2 was loaded with 10-130 electrons per particle using γ-irradiation of acidic TiO2 colloid solutions containing 2-propanol. The study is based on time-resolved kinetics and reactants and products analysis. The reduction of NO by e(TiO2)(-) is interpreted in terms of competition between a reaction path leading to formation of NH3 and a path leading to N2O and N2. The proposed mechanism involves consecutive one-electron transfers of NO, and its reduction intermediates HNO, NH2O(•), and NH2OH. The results show that e(TiO2)(-) does not reduce N2O and N2. Second-order rate constants of e(TiO2)(-) reactions with NO (740 ± 30 M(-1) s(-1)) and NH2OH (270 ± 30 M(-1) s(-1)) have been determined employing the rapid-mixing stopped-flow technique and that with HNO (>1.3 × 10(6) M(-1) s(-1)) was derived from fitting the kinetic traces to the suggested reaction mechanism, which is discussed in detail.
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