Electrocatalytic urea mineralization in aqueous alkaline medium using NiII cyclam-modified nanoparticulate TiO2 anodes and its relationship with the simultaneous electrogeneration of H2 on Pt counterelectrodes

被引：1

作者：

Murcio-Hernandez, S. ^{[1
]}

Rueda-Solorio, A. V. ^{[1
]}

Banda-Aleman, J. A. ^{[1
]}

Gonzalez-Nava, C. ^{[1
]}

Rodriguez, F. J. ^{[1
]}

Bustos, E. ^{[1
]}

Espejel-Ayala, F. ^{[1
]}

Rodriguez, A. ^{[1
]}

Sepulveda, S. ^{[2
]}

Manriquez, J. ^{[1
]}

机构：

[1] Ctr Invest & Desarrollo Tecnol Electroquim SC, Parque Tecnol Queretaro S-N, Pedro Escobedo 76703, Queretaro, Mexico

[2] Univ Autonoma Nuevo Leon, Ctr Innovac Invest & Desarrollo Ingn & Tecnol, San Nicolas De Los Garza, Nuevo Leon, Mexico

来源：

ARABIAN JOURNAL OF CHEMISTRY | 2020年 / 13卷 / 01期

关键词：

Ni-II cyclam electrodeposition; Nanoparticulate TiO2 electrodes; Urea mineralization; CO intermediates inhibition; H-2; electrogeneration; TETRAAZAMACROCYCLIC COMPLEXES; ELECTROCHEMICAL DECOMPOSITION; HYDROGEN-PRODUCTION; OPTICAL-PROPERTIES; TIO2(110) SURFACE; NICKEL ELECTRODES; OXIDATION; ELECTROOXIDATION; FILM; MECHANISM;

D O I：

10.1016/j.arabjc.2017.12.029

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Ni(II)cyclam-modified nanoparticulate TiO2-coated ITO electrodes (ITO/TiO2//Ni-II-cyclam) were prepared by electropolymerization of Ni(II)cyclam monomers to TiO2-coated ITO electrodes (ITO/TiO2) to improve electrocatalytic urea CO(NH2)(2) oxidation in alkaline aqueous solutions. A high value adding secondary effect was the collection of electrons at Pt cathodes, to simultaneously generate H-2 from water reduction. Ni(II)cyclam-modified ITO electrodes (ITO//Ni-II-cyclam) were also prepared by electropolymerization of Ni(II)cyclam monomers to bare ITO electrodes (ITO) for comparison purposes. In the presence of the TiO2 nanoparticles, the urea mineralization on Ni(II)cyclam coatings was doubled (23.95% - organic carbon removal at 120 min of electrolysis) compared to those without TiO2 nanoparticles (13.02% - organic carbon removal at 120 min of electrolysis). In agreement, the faradaic efficiency for H-2 generation at the Pt cathode, electrically connected to an anode having TiO2 nanoparticles (0.99 at 120 min of electrolysis), was also twice as effective than that observed when the same Pt cathode was electrically connected to an anode without TiO2 nanoparticles (0.46 at 120 min of electrolysis). The experimental results indicated that the poisoning of Ni-II centers (which is caused by an excessive production of CO intermediates during the urea oxidation on both Ni(II)cyclam-modified anodes) was strongly inhibited in the presence of the nanoparticulate TiO2 vertical bar Ni(II)cyclam junction. A final comparison between our results and those reported in selected publications revealed that the Ni(II)cyclam-modified nanoparticulate TiO2-coated ITO anodes here developed, constitutes a promising electrocatalytic system for performing direct urea mineralization at a relative short electrolysis time. Furthermore, the combination of the following phenomena: (a) effective charge separation on the semiconducting ITO vertical bar nanoparticulate TiO2 junctions, (b) remarkable capabilities of the nanoporous TiO2 films for tuning the load of OH- anions demanded by the urea oxidation and, (c) outstanding capabilities of the TiO2 nanoparticles for capturing CO intermediates (at Ti3+ donor sites), successfully promoted the enhancement of the electron external transport to Pt cathodes, and consequently improved the faradaic efficiency associated to the cathodic generation of H-2. (C) 2017 Production and hosting by Elsevier B.V. on behalf of King Saud University.

引用

页码：1641 / 1660

页数：20