Light‐Driven Alcohol Splitting by Heterogeneous Photocatalysis: Recent Advances, Mechanism and Prospects

Abstract

Splitting of alcohols into hydrogen and corresponding carbonyl compounds, also called acceptorless alcohol dehydrogenation, is of great significance for both synthetic chemistry and hydrogen production. Light‐Driven Alcohol Splitting (LDAS) by heterogeneous photocatalysis is a promising route to achieve such transformations, and it possesses advantages including high selectivity of the carbonyl compounds, extremely mild reaction conditions (room temperature and irradiation of visible light) and easy separation of the photocatalysts from the reaction mixtures. Because a variety of alcohols can be derived from biomass, LDAS can also be regarded as one of the most sustainable approaches for hydrogen production. In this Review, recent advances in the LDAS catalyzed by the heterogeneous photocatalysts are summarized, focusing on the mechanistic insights for the LDAS and aspects that influence the performance of the photocatalysts from viewpoints of metallic co‐catalysts, semiconductors, and metal/semiconductor interfaces. In addition, challenges and prospects have been discussed in order to present a complete picture of this field.

Size‐Selective Photoelectrochemical Reactions in Microporous Environments: Clark Probe Investigation of Pt@g‐C3N4 Embedded into Intrinsically Microporous Polymer (PIM‐1)

“…Unfortunately, in this case the photocurrent response is not further increasing at higher hexanol concentrations possibly due to flooding of micropores. The data are preliminary and the nature of photo‐products from this hexanol photooxidation is currently unknown, although the application of alcohols in photocatalytic hydrogen production has been reviewed [47] …”

Alternatives to Water Photooxidation for Photoelectrochemical Solar Energy Conversion and Green H2 Production

“…Moreover, alcohols have been considered as one of the most prominent sacrificial agents, which can result in an increase in PEC activity based on the "current-doubling" effect. [170,171] This phenomenon implies that each one absorbed photon can inject two electrons, thanks to the photogeneration and the intermediate radical formation from alcohols oxidation. When considering PEC approach, it is attributed to the multitimes increase in current density produced in water splitting reaction with the presence of alcohols in the electrolyte.…”

Cover Feature: Size‐Selective Photoelectrochemical Reactions in Microporous Environments: Clark Probe Investigation of Pt@g‐C3N4 Embedded into Intrinsically Microporous Polymer (PIM‐1) (ChemElectroChem 18/2021)

“…The data are preliminary and the nature of photo-products from this hexanol photooxidation is currently unknown, although the application of alcohols in photocatalytic hydrogen production has been reviewed. [47]…”