Issue 13, 2018

Necessary and sufficient conditions for the successful three-phase photocatalytic reduction of CO2 by H2O over heterogeneous photocatalysts

Abstract

Artificial photosynthesis has recently drawn an increasing amount of attention due to the fact that it allows for direct solar-to-chemical energy conversion. However, one of the basic steps of this process, namely the reduction of CO2 by H2O to afford O2 and CO2 reduction products (CO2RPs) such as HCOOH, CO, HCHO, CH3OH, and CH4, is very difficult to achieve. In contrast to the CO2 reduction in plants and homogenous systems, the reduction of CO2 to CO2RPs over heterogeneous photocatalysts was challenged by the competing reduction of H+ to H2. Unfortunately, most of the research performed so far has focused only on the reduction of CO2, rather than the characterization of the H2O oxidation and H2 production. Moreover, the fact that the heterogeneous photocatalytic reduction of CO2 into CO2RPs by H2O should satisfy several selectivity criteria has often been ignored. Herein, we propose three such evaluation criteria, namely (1) the origin of carbon in CO2RPs (determined using isotopically labeled CO2 (13CO2)), (2) the relative amount of H2 and CO2RPs produced, and (3) the amount of O2 produced by the oxidation of H2O. If all these criteria are satisfied, i.e., the carbons of CO2RPs originate from CO2, the amount of H2 produced is negligible, and a stoichiometric amount of O2 is produced by the oxidation of H2O, then CO2 introduced into the gas phase is believed to be reduced by H2O to CO2RPs in the aqueous phase.

Graphical abstract: Necessary and sufficient conditions for the successful three-phase photocatalytic reduction of CO2 by H2O over heterogeneous photocatalysts

Associated articles

Article information

Article type
Perspective
Submitted
18 11 2017
Accepted
22 2 2018
First published
28 2 2018

Phys. Chem. Chem. Phys., 2018,20, 8423-8431

Necessary and sufficient conditions for the successful three-phase photocatalytic reduction of CO2 by H2O over heterogeneous photocatalysts

K. Teramura and T. Tanaka, Phys. Chem. Chem. Phys., 2018, 20, 8423 DOI: 10.1039/C7CP07783A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements