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La red de enlaces de hidrógeno promueve la división del agua en la superficie de TiO2

Xiaochuan Ma¹, Yongliang Shi², Jianyi Liu¹

¹Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.

Journal of the American Chemical Society

|July 19, 2022

Resumen

Las redes de enlace de hidrógeno en la división del agua son cruciales. Este estudio muestra que estas redes, en superficies de dióxido de titanio, facilitan la transferencia de protones y agujeros para una división eficiente del agua bajo luz UV.

Área de la Ciencia:

Ciencias de la superficie
Fotocatálisis
Separación del agua

Sus antecedentes:

Romper el enlace OH en moléculas de agua aisladas es un desafío.
Las redes de enlace de hidrógeno influyen significativamente en la reactividad de las moléculas de agua.
Comprender estas redes es clave para la fotosíntesis natural y la fotocatálisis artificial.

Objetivo del estudio:

Investigar el papel de las redes de enlaces de hidrógeno en la división del agua a nivel molecular.
Para dilucidar el mecanismo de transferencia de protones y agujeros facilitado por estas redes.
Explorar el impacto de la cobertura de agua en la formación y función de la red de enlaces de hidrógeno.

Principales métodos:

Se utilizó la interfaz fotocatalítica prototipo H2O/anatasa-TiO2 ((001) - ((1 × 4).
Cobertura de agua controlada para formar redes de enlaces de hidrógeno por encima de una sola capa.
Se utiliza la irradiación de luz ultravioleta (UV) y la espectroscopia de fotoelectrones UV/rayos X in situ.
Se han realizado cálculos de la teoría funcional de la densidad (DFT).

Principales resultados:

Una red de enlaces de hidrógeno promueve la transferencia de protones y agujeros acoplados para la división del agua.
La irradiación UV crea un canal para la transferencia de agujeros fotoexcitados y la liberación de protones, formando grupos hidroxilo.
Los grupos hidroxilo suministran electrones, reduciendo Ti4 + a Ti3 + y creando estados de brecha.
Los cálculos de DFT confirman que la división del agua es exotérmica con la ayuda de la red de enlaces de hidrógeno.

Conclusiones:

La red de enlaces de hidrógeno es indispensable para la escisión del agua, no sólo para la actividad exótica del fotocatalizador.
Esta red interna es crucial en las interfaces acuosas / catalizadoras prácticas.
Los hallazgos ofrecen información a nivel molecular sobre los mecanismos de división del agua.

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