Photocatalytic Reduction of CO₂ on TiO₂ and Other Semiconductors

TLDR

Rising CO₂ levels and fossil‑fuel depletion threaten climate and energy security, motivating solar‑driven conversion of CO₂ into fuels such as methane or methanol for simultaneous mitigation and storage. This review surveys current heterogeneous photocatalytic strategies for reducing CO₂ on TiO₂ and other metal‑oxide, oxynitride, sulfide, and phosphide semiconductors. It examines nanostructured photocatalysts, the light‑absorption to charge‑separation and CO₂‑reduction pathway, and the metrics used to quantify their efficiency.

Abstract

Rising atmospheric levels of carbon dioxide and the depletion of fossil fuel reserves raise serious concerns about the ensuing effects on the global climate and future energy supply. Utilizing the abundant solar energy to convert CO2 into fuels such as methane or methanol could address both problems simultaneously as well as provide a convenient means of energy storage. In this Review, current approaches for the heterogeneous photocatalytic reduction of CO2 on TiO2 and other metal oxide, oxynitride, sulfide, and phosphide semiconductors are presented. Research in this field is focused primarily on the development of novel nanostructured photocatalytic materials and on the investigation of the mechanism of the process, from light absorption through charge separation and transport to CO2 reduction pathways. The measures used to quantify the efficiency of the process are also discussed in detail.