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Dinámica de enlace de hidrógeno interfacial en la deshidrogenación facilitada por la superficie del agua en TiO

Shijing Tan¹, Hao Feng¹, Qijing Zheng¹

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

Journal of the American Chemical Society

|December 18, 2019

Resumen

Rastrear el movimiento del átomo de hidrógeno durante la deshidrogenación del agua en óxidos metálicos es un desafío. Este estudio midió con precisión la deshidrogenación del agua en TiO2{\displaystyle TiO2{\text{110}} , revelando que las excitaciones vibratorias y los enlaces de hidrógeno interfaciales facilitan la transferencia de átomos de H.

Área de la Ciencia:

Ciencias de la superficie
Física y química
Ciencias de los materiales

Sus antecedentes:

Comprender la deshidrogenación interfacial del agua en los óxidos metálicos es crucial para la catálisis y la ciencia de los materiales.
El seguimiento de los átomos de hidrógeno ligero a nivel molecular presenta desafíos experimentales significativos.

Objetivo del estudio:

Para medir con precisión el proceso de deshidrogenación del agua facilitado por la superficie en los sitios terminales de dióxido de titanio (TiO2).
Aclarar el papel de la dinámica de los enlaces de hidrógeno y las excitaciones vibratorias en la deshidrogenación del agua.

Principales métodos:

Se utiliza el microscopio de túnel de barrido (STM) para mediciones precisas.
Investigó tanto H2O como D2O para rastrear la dinámica del átomo de hidrógeno y deuterio.
Resultados experimentales combinados con cálculos teóricos.

Principales resultados:

Transferencia secuencial observada de dos átomos de H (o D) desde H2O (o D2O) a sitios adyacentes de oxígeno en la superficie.
Demostró que las excitaciones vibratorias y electrónicas impulsan el proceso de deshidrogenación.
Se determinó una barrera de baja energía (70-120 meV) para la deshidrogenación en sitios estequiométricos de Ti5c, lo que indica que el H2O es menos estable que su forma disociativa.

Conclusiones:

La superficie de óxido metálico participa activamente en la deshidrogenación del agua.
Los enlaces de hidrógeno interfaciales juegan un papel clave en la asistencia de la transferencia y el intercambio de átomos de H.
Se ha revelado un nuevo mecanismo atomístico para las interacciones agua-óxido metálico, aplicable a los óxidos metálicos en general.

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