Unravelling the effect of charge dynamics at the plasmonic metal/semiconductor interface for CO2 photoreduction

Laura Collado,Anna Reynal,Carlos Escudero,Mariam Barawi,Juan M Coronado,James R Durrant,David P Serrano,Fernando Fresno,Virginia Perez-Dieste,Víctor A De La Peña O’Shea

doi:10.1038/s41467-018-07397-2

Abstract

Sunlight plays a critical role in the development of emerging sustainable energy conversion and storage technologies. Light-induced CO2 reduction by artificial photosynthesis is one of the cornerstones to produce renewable fuels and environmentally friendly chemicals. Interface interactions between plasmonic metal nanoparticles and semiconductors exhibit improved photoactivities under a wide range of the solar spectrum. However, the photo-induced charge transfer processes and their influence on photocatalysis with these materials are still under debate, mainly due to the complexity of the involved routes occurring at different timescales. Here, we use a combination of advanced in situ and time-resolved spectroscopies covering different timescales, combined with theoretical calculations, to unravel the overall mechanism of photocatalytic CO2 reduction by Ag/TiO2 catalysts. Our findings provide evidence of the key factors determining the enhancement of photoactivity under ultraviolet and visible irradiation, which have important implications for the design of solar energy conversion materials.

Highlights

Sunlight plays a critical role in the development of emerging sustainable energy conversion and storage technologies
Our study reveals that the plasmonic metal/semiconductor junction can introduce synergetic optical and electronic effects that modify the interfacial charge generation and electron transfer kinetics, driving CO2 photoreduction towards highly electron-demanding products
UV-driven CO2 photoreduction experiments show that homogenously distributed Ag NPs on the anatase TiO2 surface (Fig. 1 and Supplementary Figures 1 and 2a–o) lead to a nearly 15-fold enhancement in the CH4 production rate compared to the bare semiconductor (Fig. 1a), with which CO is obtained as the main product

Summary

Introduction

Sunlight plays a critical role in the development of emerging sustainable energy conversion and storage technologies. Surface VB studies, electrochemical measurements and DFT calculations altogether allow to describe the Ag/TiO2 interfaces as complex electronic structures resulting from the formation of IFS states due to the charge donation between surface Ti–O and Ag neighbours.

Results

Conclusion