Photoelectrochemical synthesis of Organic Molecules: Solar-Induced Electrochemical Organic Transformations

Conventional organic synthesis for many oxidation and reduction reactions rely on harsh conditions, toxic or corrosive substances, and environmentally damaging chemicals. In addition to this, competing reactions take place, some of which produce other hazardous waste products, and therefore, reaction selectivity suffers. To overcome such synthetic drawbacks an enormous effort is being devoted to find alternative processes that operate much more efficiently, requiring milder conditions to contribute to a more green economy and provide urgently needed new pathways with enhanced selectivity. Fortunately, there is a strategy that has attracted global interest from multiple disciplines that involves the use of sunlight to perform artificial photosynthesis, in which a photoelectrochemical (PEC) cell splits water into hydrogen fuel, reduces CO₂into sugar and other “solar” fuels, and more recently, convert organic chemicals into higher value products. Lately, photoanode and cathode materials have emerged as useful tools to perform organic oxidations and reductions for the chemical synthesise of important molecules, other than just oxygen. However, the vast majority of previously reported works focused on degradation of unwanted and dangerous chemicals, whereas only a small amount took an interest in solar-induced organic transformations. Herein, we have outlined some of latest research efforts in using photoelectrochemical cells to facilitate organic oxidation and reduction reactions for valuable substances that do not demand toxic reagents and expensive precious metal catalysts, and have outlined some future prospects that will enable such a technology to broaden its scope.