Visible and Near-Infrared Photothermal Catalyzed Hydrogenation of Gaseous CO2 over Nanostructured Pd@Nb2O5.

Jia Jia,Qiao Qiao,Nazir P Kherani,Paul G O'Brien,Amr S Helmy,Teng Fei,Geoffrey A Ozin,Yuchan Dong,Timothy E Burrow,Le He,Stephen J Pennycook,Kristine Liao,Laura M Reyes,Maria Varela,Mohamad Hmadeh,Doug D Perovic

doi:10.1002/advs.201600189

Abstract

The reverse water gas shift (RWGS) reaction driven by Nb2O5 nanorod‐supported Pd nanocrystals without external heating using visible and near infrared (NIR) light is demonstrated. By measuring the dependence of the RWGS reaction rates on the intensity and spectral power distribution of filtered light incident onto the nanostructured Pd@Nb2O5 catalyst, it is determined that the RWGS reaction is activated photothermally. That is the RWGS reaction is initiated by heat generated from thermalization of charge carriers in the Pd nanocrystals that are excited by interband and intraband absorption of visible and NIR light. Taking advantage of this photothermal effect, a visible and NIR responsive Pd@Nb2O5 hybrid catalyst that efficiently hydrogenates CO2 to CO at an impressive rate as high as 1.8 mmol gcat−1 h−1 is developed. The mechanism of this photothermal reaction involves H2 dissociation on Pd nanocrystals and subsequent spillover of H to the Nb2O5 nanorods whereupon adsorbed CO2 is hydrogenated to CO. This work represents a significant enhancement in our understanding of the underlying mechanism of photothermally driven CO2 reduction and will help guide the way toward the development of highly efficient catalysts that exploit the full solar spectrum to convert gas‐phase CO2 to valuable chemicals and fuels.

Highlights

Solar fuels are attracting increasing attention owing to their potential of being a viable alternative to fossil fuels
The photothermal approach to the catalytic hydrogenation of CO2 has emerged with reported conversion rates as high as mmol gcat−1 h−1 to mol gcat−1 h−1.[8,9] This tactic exploits the transformation of light into heat, generating high local temperatures in nanostructured catalysts that drive CO2 reduction reactions
The film sample was exposed to air for 24 h and a repeat measurement was conducted, more or less reproducing the original rate of 4.7 mmol gcat−1 h−1. These results demonstrate that a certain kind of chemical/surface species were generated in situ during the catalyst testing process and these species, which exist under vacuum or H2 and CO2 gas atmosphere, are influencing the photothermal catalytic reaction in a positive way

Summary

Introduction

Solar fuels are attracting increasing attention owing to their potential of being a viable alternative to fossil fuels. Www.advancedscience.com can be scaled and integrated with existing chemical and petrochemical industry infrastructure.[7] More recently, a photothermal approach in which gas-phase light-assisted hydrogenation of CO2 to useful fuels over supported metallic catalysts, which are traditionally known to be activated thermally at elevated temperatures, has been investigated. In this context, the photothermal approach to the catalytic hydrogenation of CO2 has emerged with reported conversion rates as high as mmol gcat−1 h−1 to mol gcat−1 h−1.[8,9] This tactic exploits the transformation of light into heat, generating high local temperatures in nanostructured catalysts that drive CO2 reduction reactions.

Results and Discussion

Raman Investigation of the Visible Light Induced Photothermal Effect

ASt ISt

Conclusion