Electrocatalytic Hydrogenation of Biomass-Derived Organics: A Review

Sustainable energy generation calls for a shift away from centralized, high-temperature, energy-intensive processes to decentralized, low-temperature conversions that can be powered by electricity produced from renewable sources. Electrocatalytic conversion of biomass-derived feedstocks would allow carbon recycling of distributed, energy-poor resources in the absence of sinks and sources of high-grade heat. Selective, efficient electrocatalysts that operate at low temperatures are needed for electrocatalytic hydrogenation (ECH) to upgrade the feedstocks. For effective generation of energy-dense chemicals and fuels, two design criteria must be met: (i) a high H:C ratio via ECH to allow for high-quality fuels and blends and (ii) a lower O:C ratio in the target molecules via electrochemical decarboxylation/deoxygenation to improve the stability of fuels and chemicals. The goal of this review is to determine whether the following questions have been sufficiently answered in the open literature, and if not, what additional information is required:(1)What organic functionalities are accessible for electrocatalytic hydrogenation under a set of reaction conditions? How do substitutions and functionalities impact the activity and selectivity of ECH?(2)What material properties cause an electrocatalyst to be active for ECH? Can general trends in ECH be formulated based on the type of electrocatalyst?(3)What are the impacts of reaction conditions (electrolyte concentration, pH, operating potential) and reactor types?

Electrocatalytic Hydrogenolysis of Chlorophenolic Compounds by Modified Electrodes in Aqueous Medium in the Absence and the Presence of Ionic Surfactant

The electrocatalytic hydrogenolysis of different chlorophenolic compounds, namely 2-chlorophenol (2CP) and pentachlorophenol (PCP) was performed on nickel-silica (Ni-SiO2) and nickel-clay (Ni-CY) electrode catalyts. The influence of the catalytic support and the surfactant agent was studied in aqueous media at different pH. Results demonstrated that different regioselectivities were observed according to the used catalytic support. The cyclohexanone was obtained as the major product. In presence of ionic surfactants (SDS and CTAB), the investigated electrodes exhibited a promising dechlorination and hydrogenation potential of aromatic halides with high electrocatalytic activity and good stability.

New biobased tetrabutylphosphonium ionic liquids: synthesis, characterization and use as a solvent or co-solvent for mild and greener Pd-catalyzed hydrogenation processes

Phosphonium-based ionic liquids with natural organic derived anions were easily prepared and showed good performance and recyclability in Pd-catalyzed hydrogenation processes at room temperature under atmospheric H₂ pressure.