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Formación del rodio envasado en forma hexagonal como efecto de tamaño
Jing Lu Huang1, Zhi Li2, Hao Hong Duan2
1National Center for Electron Microscopy in Beijing, School of Materials Science and Engineering, Key Laboratory of Advanced Materials of Ministry of Education of China, State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University , Beijing 100084, China.
Journal of the American Chemical Society
|January 4, 2017
Resumen
Los investigadores descubrieron nanopartículas de rodio empacadas en hexágono, una nueva estructura cristalina. Este hallazgo desafía las suposiciones anteriores basadas en el rodio cúbico centrado en la cara (fcc) y abre nuevas vías para la investigación de la ciencia de los materiales.
Área de la Ciencia:
- Ciencias de los materiales
- Nanotecnología
- Física del estado sólido
Sus antecedentes:
- Las investigaciones anteriores sobre las propiedades del rodio (Rh) se centraron exclusivamente en la estructura cristalina cúbica centrada en la cara (fcc) en forma a granel.
- La diversidad estructural y el potencial de los diferentes alótropos de rodio permanecieron inexplorados.
Objetivo del estudio:
- Informar sobre el primer descubrimiento y caracterización de nanopartículas de rodio empacadas de forma hexagonal.
- Investigar los métodos de síntesis y la estabilidad de esta nueva fase Rh de hcp.
- Explorar las diferencias estructurales y energéticas entre el hcp y el rodio fcc.
Principales métodos:
- Síntesis directa de nanopartículas hcp Rh a través de la reacción solvotermal.
- Descomposición inducida por haz de electrones de las monocapas de Rh para formar hcp Rh.
- Evaluación de la estabilidad de las nanopartículas hcp Rh bajo irradiación con haz de electrones.
- Cálculos basados en principios para determinar las energías superficiales y las propiedades estructurales.
Principales resultados:
- Síntesis exitosa de nanopartículas de rodio envasadas en forma hexagonal.
- Estabilidad demostrada de las nanopartículas hcp Rh bajo irradiación de haz de electrones.
- Se observó una expansión de celosía significativa en las nanopartículas hcp Rh (6% de volumen atómico más grande) en comparación con fcc Rh.
- Los cálculos de los primeros principios indicaron una energía superficial más baja para hcp Rh, explicando la estructura cristalina dependiente del tamaño.
Conclusiones:
- El descubrimiento de nanopartículas de rodio hcp representa un avance significativo en la comprensión del polimorfismo estructural del rodio.
- La expansión de la celosía observada y la menor energía superficial de hcp Rh sugieren propiedades catalíticas o electrónicas únicas.
- Los hallazgos destacan la importancia de la forma de nanopartículas en la determinación de la estructura cristalina, impulsada por los efectos de la energía superficial.
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