Photoelectrochemical oxidation of organic substrates in organic media

Abstract

There is a global effort to convert sunlight into fuels by photoelectrochemically splitting water to form hydrogen fuels, but the dioxygen byproduct bears little economic value. This raises the important question of whether higher value commodities can be produced instead of dioxygen. We report here photoelectrochemistry at a BiVO4 photoanode involving the oxidation of substrates in organic media. The use of MeCN instead of water enables a broader set of chemical transformations to be performed (e.g., alcohol oxidation and C-H activation/oxidation), while suppressing photocorrosion of BiVO4 that otherwise occurs readily in water, and sunlight reduces the electrical energy required to drive organic transformations by 60%. These collective results demonstrate the utility of using photoelectrochemical cells to mediate organic transformations that otherwise require expensive and toxic reagents or catalysts.

Heterostructured Bismuth Vanadate/Cobalt Phosphate Photoelectrodes Promote TEMPO‐Mediated Oxidation of 5‐Hydroxymethylfurfural

“…Although BiVO 4 has emerged as one of the most promising metal oxide‐based photoanodes for OER, it has been established that surface modifications, for example with catalysts such as cobalt phosphate (CoPi), Co 3 O 4 , or transition metal oxyhydroxides, are required to mitigate charge recombination losses. However, such modifications have not been applied to BiVO 4 photoanodes for enhancing redox‐mediated alcohol oxidations because it was presumed that they would promote OER in favor over mediator oxidation …”

Photokatalyse und Elektrochemie: Ein neues Bündnis in der organischen Synthese

“…In der klassischen Photoelektrokatalyse wird ein elektrochemisches System verwendet, in dem eine der Elektroden aus einem photoresponsiven Material (meist einem Halbleiter‐PC) besteht oder mit diesem beschichtet ist. Diese Methode hat etliche Anwendungen gefunden, auch einige in der organischen Synthese –. In einem sehr aktuellen Beispiel wurde Hämatit als robuste Photoanode für die Funktionalisierung von aromatischen C(sp 2 )‐H‐Bindungen mit stickstoffbasierten Nukleophilen, wie z.…”

Interfacial Photoelectrochemical Catalysis: Solar‐Induced Green Synthesis of Organic Molecules

“…The PEC oxidation of organic substrates in nonaqueous media was reported by Li et al . The first type of reaction tested was the selective oxidation of benzyl alcohol to benzaldehyde, and the second was the more difficult (since this type of reaction is typically done in the presence of toxic chemicals and precious metal catalysts) C−H oxidation of cyclohexene to cyclohexenone and tetralin to 1‐tetralone (Scheme ).…”