Electrochemical Hydrogenation Research Articles

Insight into the Interaction of Furfural with Metallic Surfaces in the Electrochemical Hydrogenation Process.

Electrocatalytic hydrogenation of furfural on metal surfaces has become an important research subject due to the potential of the reaction product 2-methylfuran as a renewable energy resource. Identifying effective determinants in this reaction process requires a thorough investigation of the complex electrode-electrolyte interactions, which considers a variety of the influential components. In this work, in operando electrochemical Raman Spectroscopy and Molecular Dynamics simulations were utilized to investigate different characteristics of the interface layer in the electrocatalytic hydrogenation of furfural. Hereby, the influence of applied potentials, electrode material, and electrolyte composition were investigated in detail. The studied parameters give an insight into furfural's binding situation, molecular orientation, and reaction mechanism.

Critical role of hydrogen sorption kinetics in electrocatalytic CO2 reduction revealed by on-chip in situ transport investigations

Precise understanding of interfacial metal−hydrogen interactions, especially under in operando conditions, is crucial to advancing the application of metal catalysts in clean energy technologies. To this end, while Pd-based catalysts are widely utilized for electrochemical hydrogen production and hydrogenation, the interaction of Pd with hydrogen during active electrochemical processes is complex, distinct from most other metals, and yet to be clarified. In this report, the hydrogen surface adsorption and sub-surface absorption (phase transition) features of Pd and its alloy nanocatalysts are identified and quantified under operando electrocatalytic conditions via on-chip electrical transport measurements, and the competitive relationship between electrochemical carbon dioxide reduction (CO2RR) and hydrogen sorption kinetics is investigated. Systematic dynamic and steady-state evaluations reveal the key impacts of local electrolyte environment (such as proton donors with different pKa) on the hydrogen sorption kinetics during CO2RR, which offer additional insights into the electrochemical interfaces and optimization of the catalytic systems.

Electrocatalytic hydrogenation and oxidation of glucose and xylose on mesoporous carbon-supported Au nanocatalysts

Electrocatalytic conversion of hemicellulose-derived glucose and xylose presents a sustainable approach to utilize renewable energy (e.g. solar, wind) to produce value-added chemicals. In this work, the electrochemical hydrogenation and oxidation of glucose and xylose at ambient conditions were studied using dispersed, mesoporous Sibunit Carbon (SC)-supported Au nanocatalysts (SC/AuNPs) with different cluster sizes (4.4 nm, 5.9 nm, 10-30 nm), providing novel results on the cluster size - activity relation. For the electrocatalytic hydrogenation (ECH) of glucose and xylose into sorbitol and xylitol, respectively, higher conversion rates were obtained when more negative potentials were applied. This indicates that the hydrogenation reaction proceeds concurrently with hydrogen evolution reaction (HER). SC/AuNPs with smaller Au clusters were more active towards glucose or xylose ECH at all potentials applied. The selectivity (Faradaic efficiency) increased towards more negative potentials for glucose ECH but followed an opposite trend for xylose ECH. Analysis using in-situ FTIR-ATR spectroscopy showed that water adsorption which leads to HER, was more extensive in xylose solution than in glucose solution at lower potentials. This would indicate greater inhibition of xylose ECH than glucose ECH at more negative potentials. The electrocatalytic oxidation (ECO) of glucose and xylose to gluconic acid and xylonic acid, respectively, was observed to occur at -0.05, +0.3, and +0.4 V (vs Ag/AgCl) using the present electrocatalytic set up. Constant-potential electrolysis at these potentials showed differences in ECO rate depending on the applied potential and average Au cluster size. The highest glucose and xylose ECO rate was obtained for the SC/AuNPs with the smallest average Au cluster size (4.4 nm) at +0.3 V. Constant-potential electrolysis of the sugars at +0.3 V using this catalyst resulted in 42 % yield of gluconic acid and 32 % yield of xylonic acid in 6 hours, both with a very low Au loading of 0.08 % wt.. These results show the strong influence of Au cluster size on the catalytic activities of SC/AuNPs toward sugar ECH or ECO.

Supercapacitor Properties of rGO-TiO2 Nanocomposite in Two-component Acidic Electrolyte

The electrochemical properties of the highly porous reduced graphene oxide/titanium dioxide (rGO/TiO2) nanocomposite were studied to estimate the possibility of using it as a supercapacitor electrode. Granular aerogel rGO/TiO2 was used as an initial material for the first time of manufacturing the electrode. For the aerogel synthesis, industrial TiO2 Hombikat UV100 with a high specific surface area and anatase structure was used, and the aerogel was carried out with hydrazine vapor. Porous structure and hydrophilic-hydrophobic properties of the nanocomposite were studied with a method of standard contact porosimetry. This is important for a supercapacitor containing an aqueous electrolyte. It was found that the hydrophilic specific surface area of the nanocomposite was approximately half of the total surface area. As a result of electrochemical hydrogenation in the region of zero potential according to the scale of a standard hydrogen electrode, a reversible Faraday reaction with high recharge rate (exchange currents) was observed. The characteristic charging time of the indicated Faraday reaction does not exceed several tens of seconds, which makes it possible to consider the use of this pseudocapacitance in the systems of fast energy storage such as hybrid supercapacitors. Sufficiently high limiting pseudo-capacitance (about 1200 C/g TiO2) of the reaction was obtained.

Controlling the electrochemical hydrogen generation and storage in graphene oxide by in-situ Raman spectroscopy

Hydrogen, generated from water splitting, is postulated as one of the most promising alternatives to fossil fuels. In this context, direct hydrogen generation by electrolysis and fixation to graphene oxide in an aqueous suspension could overcome storage and distribution problems of gaseous hydrogen. This study presents time-resolved determination of the electrochemical hydrogenation of GO by in-situ Raman spectroscopy, simultaneous to original functional groups elimination. Hydrogenation is found favoured by dynamic modulation of the electrochemical environment compared to fixed applied potentials, with a 160% increase of C–H bond formation. Epoxide groups suppression and generated hydroxide groups point at these epoxide groups being one of the key sites where hydrogenation was possible. FTIR revealed characteristic symmetric and asymmetric stretching vibrations of C–H bonds in CH 2 and CH 3 groups. This shows that hydrogenation is significantly also occurring in defective sites and edges of the graphene basal plane, rather than H-Csp 3 groups as graphane. We also determined a −0.05 V RHE reduction starting potential in alkaline electrolytes and a 150 mV cathodic delay in acid electrolytes. The identified key parameters role, together with observed diverse C-H x groups formation, points at future research directions for large-scale hydrogen storage in graphene.

Facile electrochemical preparation of NiFeP submicron-spheres as an efficient electrocatalyst for the electrochemical hydrogenation of 4-nitrophenol at neutral pH

Electrochemical hydrogenation with water as the proton source serves as a clean and sustainable alternative to the removal and upcycling of 4-nitrophenol (4-NP), one of the major toxic pollutants commonly present in industrial wastewater effluents, into value-added chemicals (e.g., 4-aminophenol), but the development of high-performance electrocatalyst for electrochemical hydrogenation of 4-NP (e-NPR) at neutral pH remains challenging. Herein, we represent the facile electrochemical synthesis of micro-structured nickel-iron phosphide (microNiFeP), which acts as an efficient electrocatalyst in catalyzing hydrogen evolution reaction (HER) and e-NPR at neutral pH. The effects of electrosynthetic conditions on the physicochemical and electrocatalytic properties of microNiFeP were investigated and optimized. microNiFeP, prepared with optimized conditions, consisted of submicron-sized spheres (diameter: ∼ 200 nm) with wrinkled surface and exhibited promising HER activity, reaching a turnover frequency (TOF) of 47.18 ± 4.10 h-1 at − 0.2 V vs. reversible hydrogen electrode (RHE) at pH 7 in the absence of 4-NP. In the presence of 4-NP, however, microNiFeP exhibited high e-NPR activity and selectivity against HER. Notably, microNiFeP showed a TOF of 5.12 ± 0.48 h-1 for e-NPR at 0.0 V vs. RHE and enabled conversion of 89.6 ± 3.3 % with a Faradic efficiency of 81.98 ± 5.08 % for 4-aminophenol production after 8-h-controlled-potential electrolysis at − 0.2 V vs. RHE. Mechanistic studies reveal that e-NPR at microNiFeP involved the transfer of 5.3 ∼ 5.8 electrons and may involve the formation of 4,4'-dihydroxyazobenzene as one of the side products.

Electrochemical Hydrogenation of CO on Cu(100): Insights from Accurate Multiconfigurational Wavefunction Methods.

Copper (Cu) remains the most efficacious electrocatalyst for electrochemical CO2 reduction (CO2R). Its activity and selectivity are highly facet-dependent. We recently examined the commonly proposed rate-limiting CO hydrogenation step on Cu(111) via embedded correlated wavefunction (ECW) theory and demonstrated that only this higher-level theory yields predictions consistent with potential-dependent experimental kinetics. Here, to understand the differing activities of Cu(111) and Cu(100) in catalyzing CO2R, we explore CO hydrogenation on Cu(100) using ECW theory. We predict that the preferred pathway involves the reduction of adsorbed CO (*CO) to *COH via proton-coupled electron transfer (PCET) at working potentials, although *CHO also may form with a kinetically accessible but higher barrier. In contrast, our earlier work on Cu(111) concluded that *COH and *CHO formation via PCET are equally feasible. This work illustrates one possible origin of the facet dependence of CO2R mechanisms and products on Cu electrodes and sheds light on how the selectivity of CO2R electrocatalysts can be controlled by the surface morphology.

Transient Stabilization Effect of CO2 in the Electrochemical Hydrogenation of Azo Compounds and the Reductive Coupling of α‐Ketoesters

AbstractThe carbon dioxide (CO2) capture and utilization has attracted a great attention in organic synthesis. Herein, an unpresented transient stabilization effect (TSE) of CO2 is disclosed and well applied to the electrochemical hydrogenation of azo compounds to hydrazine derivatives. Mechanistic experiments and computational studies imply that CO2 can capture azo radical anion intermediates to protect the hydrogenation from potential degradation reactions, and is finally released through decarboxylation. The promotion effect of CO2 was further demonstrated to work in the preliminary study of electrochemical reductive coupling of α‐ketoesters to vicinal diol derivatives. For the electrochemical reductive reactions mentioned above, CO2 is indispensable. The presented results shed light on a different usage of CO2 and could inspire novel experimental design by using CO2 as a transient protecting group.

Transient Stabilization Effect of CO2 in the Electrochemical Hydrogenation of Azo Compounds and the Reductive Coupling of α-Ketoesters.

The carbon dioxide (CO2 ) capture and utilization has attracted a great attention in organic synthesis. Herein, an unpresented transient stabilization effect (TSE) of CO2 is disclosed and well applied to the electrochemical hydrogenation of azo compounds to hydrazine derivatives. Mechanistic experiments and computational studies imply that CO2 can capture azo radical anion intermediates to protect the hydrogenation from potential degradation reactions, and is finally released through decarboxylation. The promotion effect of CO2 was further demonstrated to work in the preliminary study of electrochemical reductive coupling of α-ketoesters to vicinal diol derivatives. For the electrochemical reductive reactions mentioned above, CO2 is indispensable. The presented results shed light on a different usage of CO2 and could inspire novel experimental design by using CO2 as a transient protecting group.

Synthesis of molybdenum-cobalt nanoparticles decorated on date seed-derived activated carbon for the simultaneous electrochemical hydrogenation and oxidation of furfural into fuels

Recently, scalable electrochemical processes have been developed to convert furfural into fuels. The conversion of furfural requires electrode materials that are cost-effective and highly stable. Herein, molybdenum‑cobalt nanoparticles on nitrogen doped date seed-derived activated carbon (N-MoCo/C) have been used as a bifunctional electrocatalyst, enabling simultaneous electrochemical hydrogenation (ECH) and oxidation (ECO) of furfural to fuels and value-added chemicals. An N-MoCo/C catalyst with varying Mo/Co ratios on nitrogen-doped date-seed-derived activated carbon was prepared, and its structural characterization was carried out by X-ray diffraction. Cyclic voltammetry and electrochemical impedance spectroscopy were carried out to determine the electrochemically active surface area, the electrode resistivity, and the electrocatalytic activity of furfural through ECO and ECH. In particular, N-MoCo/C catalysts with different Mo:Co ratios were used to tune the ECH and ECO of furfural and the yields and selectivity of the resulting products. A Mo:Co ratio of 3:1 in N-MoCo/C led to the most efficient conversion of furfural to furoic acid through ECO and furfural alcohol through ECH. Response Surface Methodology (RSM) and a central composite design (CCD) was used to study the electrochemical transformation of furfural. This study opens up possibilities for the simultaneous ECH and ECO of furfural to value-added chemicals under optimized conditions.

Electrochemical hydrogenation of Ti–Ni powder mechanochemically alloyed with titanium

The paper reports the results of the study aimed to increase the Ti2Ni phase content in Ti–Ni powder by mechanochemical alloying with titanium and subsequent heat treatment. The interaction of the alloyed Ti–Ni powder with hydrogen was investigated. It is shown that before mechanochemical alloying the phase composition of Ti–Ni powder included three phases: TiNi (B2, B19’), Ti2Ni, and Ni3Ti. After mechanochemical alloying followed by heat treatment, Ti–Ni powder contained TiNi (B2, B19’) and Ti2Ni phases, where the latter phase was of different genesis. Ti2Ni (I) phase was present in Ti–Ni powder before mechanochemical alloying; its unit cell size after alloying with titanium remained unchanged and was equal to 1.1283 ± 5 × 10−4 nm Ti2Ni (II) phase was formed during mechanochemical alloying; its lattice parameter decreased as the Ti content in Ti–Ni powder during alloying increased. Electrochemical hydrogenation of the Ti–Ni (85 wt%) – Ti (15 wt%) powder mixture increased the cell size of both Ti2Ni (I) and Ti2Ni (II), which indicates the interaction of hydrogen with both Ti2Ni phases. The Ti2Ni (I) cell volume increased by 0.3% due to solid solution formation, and the Ti2Ni (II) cell volume increased by 17.6% due to hydride formation. The Ti2Ni (II) phase formed by mechanochemical alloying is more prone to interact with hydrogen with the formation of Ti2NiHx hydride than with the Ti2Ni (I) phase present in Ti–Ni powder before alloying. The number of hydrogen atoms in chemical formulas of Ti2Ni (II)-based hydride was determined. Hydrogenation of the Ti–Ni (85 wt%) – Ti (15 wt%) powder mixture for 90 min caused formation of Ti2NiH1.9 hydride; 360 min hydrogenation yielded Ti2NiH2.8 hydride.

Tafel-Kinetics-Controlled High-Speed Switching in a Electrochemical Graphene Field-Effect Transistor.

Graphene field-effect transistors (FETs) have attracted tremendous attention owing to the single-atomic-layer thickness and high electron mobility for potential applications in next-generation electronics. With regards to switching methodology, the electric-field-induced metal-insulator transition offers a new strategy to produce a large on/off current ratio through reversible electrochemical hydrogenation of the graphene channels. Therefore, the performance of such electrochemical graphene FETs greatly relies on the kinetics of hydrogenation reaction. Here, we show that the switching time can be systemically controlled by the applied gate voltages and geometries of graphene channels. The turn-on and turn-off time display an exponential dependence on the gate voltages, manifesting the dominated Tafel-form kinetics of hydrogenation reaction in a two-dimensional limit. Moreover, the turn-off time is inversely proportional to the channel width but independent of the length, while the turn-on time relies on both the width and length, as well as the off-state gate voltage and duration. Our work improves the response time to the magnitude of tens of microseconds and advances the application of graphene-based electronic devices.

PH Driven Pathways to Promote the Electrochemical Hydrogenation of Phenol and Other Aromatic Hydrocarbons

The electrochemical hydrogenation (ECH) of bio-mass derived compounds is an attractive alternative to traditional thermochemical hydrogenation (TCH) methods that are used in the U.S. chemical and petroleum industries to produce value-added fuels and chemicals. TCH uses high pressures and temperatures, along with an external source of hydrogen gas typically produced via methane reformation; these requirements make it an energy intensive process. ECH has the advantages of operating near ambient conditions and sourcing the participating hydrogen from the aqueous electrolyte solution, resulting in reduced energy costs and CO2 emissions compared to TCH. The applied potential provides an additional parameter for controlling selectivity, which makes ECH more suitable to handle the wide chemical variability of biomass-derived feedstocks.Aromatic hydrocarbons are of interest as model compounds for lignocellulosic bio-oil [1]. The ECH of aromatic hydrocarbons proceeds with high faradaic efficiency (FE) at low overpotentials, however, the ECH turnover rate remains low at these potentials. There is no simple fix to this, as any increase in overpotential, to increase ECH rate, will reduce the reaction FE due to competition with the hydrogen evolution reaction (HER). In this work we address the need for a more fundamental understanding of ECH systems to promote high turnover rates at low overpotentials. Specifically for phenol TCH, it is well known that the hydrogenation is limited by the formation/addition of surface adsorbed hydrogen. The current ECH literature draws on these TCH studies and assumes that phenol ECH is also limited by surface adsorbed hydrogen [2]. Thus, most ECH work is done is acidic media, where the kinetics of surface adsorbed hydrogen formation are fastest on platinum [3]. HER, however, is also faster on platinum in acidic media [4], making it more difficult to achieve high faradaic efficiency.Because of this limited scope of investigation, the impact of electrolyte chemistry, i.e. pH, on ECH kinetics has only been sparingly investigated. In this work, we investigate a new pathway for enhanced rates at low overpotentials, driven by the acid-base chemistry of reactants and using electrolyte pH to promote dissociative adsorption. By tailoring the electrolyte pH based on the pKa of the reactant molecule, we can lower the barrier associated with the first hydrogenation step, improving overall reaction kinetics. We demonstrate this effect with phenol ECH at various pH electrolyte on low-index single crystal electrodes using rotating disk electrode voltammetry and chrono-amperometry with product analysis. The ECH of acetophenone and benzaldehyde are also included to compare the effect of different functionalities on the phenyl ring. We report on the structural sensitivity, influence of pH and resulting electric field effects, and present new mechanistic insights for phenol ECH. With these insights we propose methods to promote higher ECH rates at lower overpotentials.

Insights into the Electrochemical Hydrogenation of Phenol

Traditional thermochemical hydrogenation (TCH) methods that are used in the U.S. chemical and petroleum industries to produce value-added fuels are highly energy intensive. To achieve hydrogenation, they require high temperature and pressure, along with an external source of hydrogen that usually comes from methane reformation. Electrochemical hydrogenation (ECH) is an attractive alternative that replaces the thermal driving force with an applied electrical potential, allowing ECH to operate near ambient conditions. The participating hydrogen comes from the aqueous electrolyte solution rather than externally produced hydrogen. These features of ECH lower its energy demand compared to TCH and result in less greenhouse gas emissions. ECH is also promising for the utilization of biomass feedstocks and could be powered directly by renewable energy, further minimizing its environmental impact.Aromatic hydrocarbons are of interest as model compounds for lignocellulosic bio-oil [1]. The ECH of aromatic hydrocarbons proceeds with high faradaic efficiency (FE) at low overpotentials, however, the ECH turnover rate remains low at these potentials. There is no simple fix to this because any increase in overpotential to increase ECH rate will reduce the reaction FE due to competition with the hydrogen evolution reaction (HER). In this work we address the need for a more fundamental understanding of ECH systems to promote high turnover rates at low overpotentials. In phenol TCH, it is well known that the hydrogenation is limited by the formation/addition of surface adsorbed hydrogen. The current ECH literature draws on these TCH studies and assumes that phenol ECH is also limited by surface adsorbed hydrogen [2]. Thus, most ECH work is done is acidic media, where the kinetics of surface adsorbed hydrogen formation are fastest on platinum [3]. HER, however, is also faster on platinum in acidic media [4], making it more difficult to achieve high FE.Because of this limited scope of investigation, the impact of electrolyte chemistry, i.e. pH, on ECH kinetics has only been sparingly investigated. In this work, we investigate a new pathway for enhanced rates at low overpotentials, driven by the acid-base chemistry of reactants and using electrolyte pH to promote dissociative adsorption. By tailoring the electrolyte pH based on the pKa of the reactant molecule, we can lower the barrier associated with the first hydrogenation step, improving overall reaction kinetics. We demonstrate this effect with phenol ECH at various pH electrolyte on low-index single crystal electrodes using rotating disk electrode voltammetry and chrono-amperometry with product analysis. We report on the structural sensitivity, influence of pH and resulting electric field effects, and present new mechanistic insights for phenol ECH. With these insights we propose methods to promote higher ECH rates at lower overpotentials.

Pentlandite Catalysts for the Electrochemical Hydrogenation of Alkynols in a Zero-Gap Electrolyzer

Electrosynthetic methods are considered to be crucial in the sustainable transformation of the chemical industry. Being an integral part of many synthetic pathways, the electrification of hydrogenation reactions gained increasing interest in recent years. However, for the large-scale industrial application of electrochemical hydrogenations, low-resistance zero-gap electrolyzers operating at high current densities and high substrate concentrations, ideally applying noble-metal-free catalyst systems, are required. In this work, we demonstrate the successful development of an electrochemical hydrogenation process towards application at the example of the semi-hydrogenation of alkynols. Because of their conductivity, stability, and stoichiometric flexibility, transition metal sulfides were thoroughly investigated as promising electrocatalysts for electrochemical hydrogen evolution but remain scarcely investigated for electrochemical hydrogenations. An initial screening of a series of first-row transition metal sulfides of the pentlandite class revealed promising activity for the electrochemical hydrogenation of alkynols in water and methanol. Based on these findings, selected catalysts were incorporated into a zero-gap electrolyzer, thereby enabling the hydrogenation of alkynols at current densities of up to 1 A cm-2, Faraday efficiencies of up to 75 %, and an alkene selectivity of 90 %. In this scalable setup we demonstrate high stability of the catalyst and the electrode for at least 100 h. Altogether, we illustrate the successful integration of a sustainable catalyst into a scalable zero-gap electrolyzer establishing electrosynthetic methods in an application-oriented manner. Figure 1

Fouling of Cu Catalysts during Electrochemical Hydrogenation and Hydrogenolysis of Furfural in Acidic Media

Electrochemical processes offer sustainable means of production when coupled with renewable energy. While thermocatalytic processes require external hydrogen gas for reduction reactions, which generates copious amounts of CO2 in the generation of the hydrogen gas, electrochemical processes have the ability to use protons from the electrolyte in lieu of external hydrogen gas as a reactant. In addition to eliminating the hydrogen gas reactant, electrochemical processes can operate at room temperature and pressure. The development of electrochemical reactors for transformation of biomass derived species is of growing interest for the sustainable production routes it enables of various fine chemicals and fuels. Furfural (FF), one such biomass derived species can be electrochemically reduced to furfuryl alcohol (FA), a resin, and 2-methylfuran (MF), a potential fuel. To produce both FA and MF, acidic electrolytes and Cu catalysts can be used. While Cu electrodes allow for high selectivity to furfuryl alcohol or 2-methylfuran, the Cu electrodes suffer from stability issues caused by things such as fouling over longer durations of electrolysis.In this work, we intentionally operated FF ECH under conditions to promote fouling so that the impact of fouling could be investigated. This consisted of 200mM FF in the catholyte with pH 0 electrolyte in 20:80 acetonitrile:water. We used a Cu flag working electrode of 6cm2. We then recycled the Cu electrode for 3 runs of ECH at 3 hours, refreshing the catholyte after each run. A polymeric substance was observed on the Cu electrode surface after multiple uses which had identical IR spectroscopic features to poly(furfuryl alcohol). The impact of the polymeric coating was investigated further using electrochemical impedance spectroscopy, the chemical characterization was determined using x-ray photoelectron spectroscopy, and morphology was imaged using scanning electron microscopy.

Efficient Electrochemical Hydrogenation of Unsaturated Organics Using Noble-Metal-Free Pentlandite Catalysts

Electrocatalytic hydrogenation reactions (ECH) increasingly emerge as promising methods in the reductive production of base- and fine-chemicals. When driven by renewable energies, it constitutes a sustainable option circumventing the need for gaseous hydrogen, high pressure conditions as well as stoichiometric reducing agents which are associated with surplus waste formation. Furthermore, ECH processes can be operated under mild conditions close to room temperature and using green solvents such as water as proton source. Beyond these substantial advantages, an ideal ECH-process requires readily available, cheap and durable electrocatalysts capable of preplacing predominant noble metals to become industrially competitive. Along this line, much can be learned from natural enzymatic systems handling hydrogen. Inspired by the active sites of hydrogenases, which feature abundant transition metals in a sulfidic environment, we employed highly conductive 3d-metal chalcogenides of pentlandite type as highly efficient and cheap electrocatalysts for the ECH of unsaturated organic chemicals. Based on this inspiring compound class we demonstrate the relevant parameters to suppress the formation of parasitic hydrogen in favor for hydrogenations. Additionally, we outline the necessary interplay of material science as well as reactor engineering all the way from an initially promising catalytic material to a scalable sustainable electrochemical cell with industrial potential. Figure 1

Promoting the electrochemical hydrogenation of furfural by synergistic Cu0−Cu+ active sites

Promoting the electrochemical hydrogenation of furfural by synergistic Cu0−Cu+ active sites

Understanding the electrochemical hydrogenation of acetone on Pt single crystal electrodes

• Pt(1 1 0) electrode is the only basal plane active for the acetone electroreduction. • The inclusion of (1 1 1) steps on (1 1 0) terraces slightly alters the behavior of Pt(1 1 0). • Insertion of (1 0 0) steps on (1 1 0) terraces decreases the activity. • Sulfate competes with acetone for the surface sites. The heterogeneous upgrading of biomass by means of electrocatalytic hydrogenation is an attractive way to refine products for industrial and pharmaceutical purposes. Also, the efficient electrochemical reduction of carbonyl compounds can act as hydrogen vectors, and therefore energy vectors. In this manuscript, we render further fundamental insights into the electrochemical reduction of acetone as a model molecule of carbonyl compounds. The structural sensitivity of the reaction is demonstrated by using platinum single crystal electrodes with low Miller indices and stepped electrodes with (1 1 0) terraces and either (1 1 1) or (1 0 0) monoatomic steps. Among the basal planes, Pt(1 1 0) is the only one active for the electroreduction of acetone. The inclusion of (1 1 1) steps on the (1 1 0) terraces does not significantly alter the behavior of Pt(1 1 0), but increasing the (1 0 0) step density has been observed to decrease the activity. We attribute this different performance to a geometrical effect of the active sites. By using different supporting electrolytes, we have found that sulfate competes with acetone for the surface sites, thus modifying the adlayer interfacial structure and hampering acetone reactivity.

Electrochemical Hydrogenation, Hydrogenolysis, and Dehydrogenation for Reductive and Oxidative Biomass Upgrading Using 5-Hydroxymethylfurfural as a Model System

Electrochemical Hydrogenation, Hydrogenolysis, and Dehydrogenation for Reductive and Oxidative Biomass Upgrading Using 5-Hydroxymethylfurfural as a Model System