Introduction to solar fuels and chemicals: photocatalytic water splitting and CO 2 reduction themed collection

Ryu Abe; Yun Hau Ng; Osamu Ishitani; Kazunari Domen

doi:10.1039/D4SE90069C

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DOI: 10.1039/D4SE90069C (Editorial) Sustainable Energy Fuels, 2024, Advance Article

Introduction to solar fuels and chemicals: photocatalytic water splitting and CO₂ reduction themed collection

Ryu Abe^a, Yun Hau Ng^b, Osamu Ishitani^c and Kazunari Domen^de
^aDepartment of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
^bLow-Carbon and Climate Impact Research Centre, School of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong SAR 999077, China
^cDepartment of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739 8526, Japan
^dResearch Initiative for Supra-Materials, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan
^eOffice of University Professors, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656, Japan

Photocatalytic water splitting and CO₂ reduction, utilizing semiconductors and/or metal complexes, have become a forefront research field, with the aim of achieving the sustainable production of clean fuels (e.g., H₂) and chemicals (e.g., hydrocarbons) through the harnessing of abundant solar light energy.

In recent decades, the scientific community has witnessed rapid advancement in the field of photocatalytic water splitting, encompassing various aspects ranging from fundamental research focused on the development of photocatalytic materials and reaction systems, to the integration of these materials into devices and larger scale demonstrations under natural sunlight. However, creating the ultimate photocatalyst material capable of achieving practically high solar-to-hydrogen conversion efficiencies (higher than 5%) by effectively harnessing a wide range of the solar light spectrum, remains a challenge.

While CO₂ is commonly regarded as a waste byproduct and a greenhouse gas resulting from the combustion of fossil fuels, it is noteworthy that in nature, CO₂ serves as the fundamental building block for chemical synthesis and energy storage. A variety of chemical fuels and chemicals can also be derived via photocatalytic CO₂ reduction. Significant advancements have been made in this research field over the past few decades, particularly focusing on metal complex photocatalysts, toward improving key catalyst parameters, including product selectivity, reaction rate, and energetic efficiency. Innovative approaches, such as the utilization of metal organic frameworks (MOF) and hybrid systems involving semiconductors, have paved the way for advancing CO₂ utilization. However, several challenges still remain, such as utilization of water as an electron source and diversifying the range of products beyond the two-electron reduction products, CO and HCOOH.

This themed collection in Sustainable Energy & Fuels aims to showcase the recent advancements in the field of photocatalytic water splitting and CO₂ reduction, covering semiconductor materials chemistry, photoelectrochemistry, nanotechnology, co-catalysts with high selectivity, molecular catalyst chemistry, spectroscopy, theoretical studies, and system design for practical applications.

Introduction to solar fuels and chemicals: photocatalytic water splitting and CO2 reduction themed collection

Introduction to solar fuels and chemicals: photocatalytic water splitting and CO₂ reduction themed collection