In this review, we highlight the use of organic photoredox catalysts in a myriad of synthetic transformations with a range of applications. This overview is arranged by catalyst class where the photophysics and electrochemical characteristics of each is discussed to underscore the differences and advantages to each type of single electron redox agent. We highlight both net reductive and oxidative as well as redox neutral transformations that can be accomplished using purely organic photoredox-active catalysts. An overview of the basic photophysics and electron transfer theory is presented in order to provide a comprehensive guide for employing this class of catalysts in photoredox manifolds.

Organic Photoredox Catalysis

This paper reviews recent progress made in identifying electrocatalysts for carbon dioxide (CO2) reduction to produce low-carbon fuels, including CO, HCOOH/HCOO−, CH2O, CH4, H2C2O4/HC2O4−, C2H4, CH3OH, CH3CH2OH and others. The electrocatalysts are classified into several categories, including metals, metal alloys, metal oxides, metal complexes, polymers/clusters, enzymes and organic molecules. The catalyts' activity, product selectivity, Faradaic efficiency, catalytic stability and reduction mechanisms during CO2 electroreduction have received detailed treatment. In particular, we review the effects of electrode potential, solution–electrolyte type and composition, temperature, pressure, and other conditions on these catalyst properties. The challenges in achieving highly active and stable CO2 reduction electrocatalysts are analyzed, and several research directions for practical applications are proposed, with the aim of mitigating performance degradation, overcoming additional challenges, and facilitating research and development in this area.

A review of catalysts for the electroreduction of carbon dioxide to produce low-carbon fuels

Current status and future perspectives in atom transfer radical polymerization (ATRP) are presented. Special emphasis is placed on mechanistic understanding of ATRP, recent synthetic and process development, and new controlled polymer architectures enabled by ATRP. New hybrid materials based on organic/inorganic systems and natural/synthetic polymers are presented. Some current and forthcoming applications are described.

Atom Transfer Radical Polymerization (ATRP): Current Status and Future Perspectives

Electrochemistry represents one of the most intimate ways of interacting with molecules. This review discusses advances in synthetic organic electrochemistry since 2000. Enabling methods and synthetic applications are analyzed alongside innate advantages as well as future challenges of electroorganic chemistry.

Synthetic Organic Electrochemical Methods Since 2000: On the Verge of a Renaissance

Two major energy-related problems confront the world in the
next 50 years. First, increased worldwide competition for
gradually depleting fossil fuel reserves (derived from past
photosynthesis) will lead to higher costs, both monetarily and politically. Second, atmospheric CO_2 levels are at their highest recorded level since records began. Further increases are predicted to produce large and uncontrollable impacts on the world climate. These projected impacts extend beyond climate to ocean acidification, because the ocean is a major sink for atmospheric CO2.1 Providing a future energy supply that is secure and CO_2-neutral will require switching to nonfossil energy sources such as wind, solar, nuclear, and geothermal energy and developing methods for transforming the energy produced by these new sources into forms that can be stored, transported, and used upon demand.

Frontiers, Opportunities, and Challenges in Biochemical and Chemical Catalysis of CO2 Fixation

The electrocarboxylation of styrene to phenylsuccinic acid and 3‐phenylpropionic acid has been realized in a diaphragmless cell, with aluminum sacrificial anodes. Yields of up to 85% of the dicarboxylic derivative have been obtained in anhydrous DMF, whereas different amounts of the monocarboxylic derivative are formed, depending upon the proticity of the medium. The effect of the nature of the proton donors and of the cathodic material has been considered and the electrocarboxylation mechanism discussed.

https://iopscience.iop.org/article/10.1149/1.2100846/pdf

Electrochemical Carboxylation of Styrene

The metal-support interactions between sulfur-doped carbon supports (SMCs) and Pt nanoparticles (NPs) were investigated, aiming at verifying how sulfur functional groups can improve the electrocatalytic performance of Pt NPs towards the oxygen reduction reaction (ORR). SMCs were synthetized, tailoring the density of sulfur functional groups, and Pt NPs were deposited by thermal reduction of Pt(acac)2 . The extent of the metal-support interaction was proved by X-ray photoelectron spectroscopy (XPS) analysis, which revealed a strong electronic interaction, proportional to the density of sulfur defects, whereas XRD spectra provided evidence of higher strain in Pt NPs loaded on SMC. DFT simulations confirmed that the metal-support interaction was strongest in the presence of a high density of sulfur defects. The combination of microstrain and electronic effects resulted in a high catalytic activity of supported Pt NPs towards ORR, with linear correlations of the half-wave potential E1/2 or the kinetic current jk with the sulfur content in the support. Furthermore, a mass activity value (550 A g-1 ) well above the United States Department of Energy target of 440 A g-1 at 0.9 V (vs. reversible hydrogen electrode, RHE), was determined.

Armando Gennaro

Papers

Electrochemical Carboxylation of Styrene

Mesoporous Carbon with Different Density of Thiophenic-Like Functional Groups and Their Effect on Oxygen Reduction.

A study of the electrochemical reduction-mechanism of ni(salophen) in dmf

Nitrogen and Sulfur Doped Mesoporous Carbons, Prepared from Templating Silica, as Interesting Material for Supercapacitors

Facile synthesis of Pd3Y alloy nanoparticles for electrocatalysis of the oxygen reduction reaction