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La supresión casi completa de la recombinación superficial en la fotoelectrolisis solar por el catalizador "Co-Pi"
Diane K Zhong1, Sujung Choi, Daniel R Gamelin
1Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States.
Journal of the American Chemical Society
|September 28, 2011
Resumen
La adición de un electrocatalizador de cobalto-fosforo-nitrógeno (Co-Pi) a los fotoánodos de vanadato de bismuto dopado con tungsteno (W:BiVO(4) mejora significativamente la oxidación del agua solar. Esta modificación de la superficie mejora la eficiencia y reduce la pérdida de energía en la división fotoelectroquímica (PEC) del agua.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- La electroquímica es electroquímica.
- Energía renovable Energía renovable.
Sus antecedentes:
- La división solar del agua es una tecnología clave para la producción de hidrógeno renovable.
- El vanadato de bismuto dopado con tungsteno (W:BiVO(4)) es un material de fotoánodo prometedor.
- Los electrocatalizadores eficientes de oxidación del agua son cruciales para mejorar el rendimiento de la división solar del agua.
Objetivo del estudio:
- Investigar el efecto de un electrocatalizador de cobalto-fosforo-nitrógeno (Co-Pi) abundante en la tierra en los fotoánodos W:BiVO ((4) para la oxidación del agua solar.
- Para evaluar la mejora del rendimiento de los fotoánodos W:BiVO(4) modificados con Co-Pi utilizando técnicas fotoelectroquímicas (PEC).
- Evaluar el potencial de esta estrategia de modificación de Co-Pi para aplicaciones solares de escisión de agua de bajo costo.
Principales métodos:
- Fabricación de W:BiVO(4) fotoánodos.
- Modificación de la superficie de W:BiVO(4) con el electrocatalizador Co-Pi.
- Mediciones fotoelectroquímicas (PEC) a pH 8, incluidos experimentos con H(2) O(2) como sustrato sustituto.
- Comparación de los resultados con los fotoanodos Co-Pi/α-Fe.
Principales resultados:
- La modificación de Co-Pi indujo un cambio catódico significativo (∼440 mV) en el potencial de inicio para la oxidación sostenida del agua PEC a pH 8.
- La interfaz de Co-Pi con W:BiVO(4) fotoánodos suprimió efectivamente las pérdidas de recombinación de agujero de electrones superficiales.
- Se logró un bajo potencial de inicio absoluto de ∼310 mV frente a RHE con el sistema Co-Pi/W:BiVO ((4).
Conclusiones:
- El fotoánodo Co-Pi/W:BiVO(4) demuestra una oxidación de agua solar altamente eficiente.
- Las mejoras observadas son prometedoras para el desarrollo de células PEC en tándem de bajo costo para la división total del agua solar.
- Esta estrategia de modificación de la superficie es aplicable a otros materiales candidatos de fotoánodos.
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