Organic Upgrading through Photoelectrochemical Reactions: Toward Higher Profits

Abstract

Aqueous photoelectrochemical (PEC) cells have long been considered a promising technology to convert solar energy into hydrogen. However, the solar‐to‐H2 (STH) efficiency and cost‐effectiveness of PEC water splitting are significantly limited by sluggish oxygen evolution reaction (OER) kinetics and the low economic value of the produced O2, hindering the practical commercialization of PEC cells. Recently, organic upgrading PEC reactions, especially for alternative OERs, have received tremendous attention, which improves not only the STH efficiency but also the economic effectiveness of the overall reaction. In this review, PEC reaction fundamentals and reactant‐product cost analysis of organic upgrading reactions are briefly reviewed, recent advances made in organic upgrading reactions, which are categorized by their reactant substrates, such as methanol, ethanol, glycol, glycerol, and complex hydrocarbons, are then summarized and discussed. Finally, the current status, further outlooks, and challenges toward industrial applications are discussed.

CoOOH/CdIn2S4 film photoanodes driving unbiased tandem cells towards simultaneous efficient oxidation of benzyl alcohol and selective generation of ethanol from CO2 reduction

“…To check the possibility, further O 18 isotope tracking investigations were conducted for the benzaldehyde products. In the CoOOH/CdIn 2 S 4 photoanode-based cell, C 6 H 5 CHO 18 (benzaldehyde) was obtained as the product in 10% H 2 O 18 /90% H 2 O 16 /alcohol electrolyte (Fig. 4c).…”

“…12–14 In addition, the products of alcohol oxidation (such as aldehydes and ketones) are more economically valuable than the products of H 2 O oxidation (usually O 2 ). 15,16 Therefore, a series of Cu 2 O-based cathode–photoanode combinations (such as Cu 2 O–BiVO 4 , Cu 2 O/Ga 2 O 3 /TiO 2 /RuO x –Mo:BiVO 4 , and Cu 2 O/GDL-Ti/NtTiO 2 /CuO) have been studied for the simultaneous achievement of CO 2 reduction and alcohol oxidation in a tandem PEC cell. 17–19 However, due to the limitations of photoanodes, the products of CO 2 reduction on Cu 2 O-based cathodes are usually C 1 products (such as CO, H 2 /CO, and formic acid) and seldom include multi-carbon (C 2+ ) products in unbiased tandem cells.…”

Nanoconfinement Enables Photoelectrochemical Selective Oxidation of Glycerol via the Microscale Fluid Effect

“…The TNT electrodes were prepared by titanium foil anodization based on our previous work. 17 Due to the operability of this method, the pore sizes of TNT anodes were adjusted by altering the voltage of the anodizing process. Scanning electron microscopy (SEM) was employed to evaluate the morphological characteristics and inner diameters of the TNTs.…”

“…The TNT electrodes were prepared by titanium foil anodization based on our previous work . Due to the operability of this method, the pore sizes of TNT anodes were adjusted by altering the voltage of the anodizing process.…”