Efficient electrocatalytic hydrogenation with a palladium membrane

Subscriber access provided by UNIV OF LOUISIANA

Article

Efficient electrocatalytic hydrogenation with a palladium membrane reactor Rebecca S. Sherbo, Aiko Kurimoto, Christopher M. Brown, and Curtis P. Berlinguette J. Am. Chem. Soc., Just Accepted Manuscript • DOI: 10.1021/jacs.9b01442 • Publication Date (Web): 17 Apr 2019 Downloaded from http://pubs.acs.org on April 17, 2019

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Journal of the American Chemical Society

Efficient electrocatalytic hydrogenation with a palladium membrane reactor Rebecca S. Sherbo,1 Aiko Kurimoto,1 Christopher M. Brown,1 Curtis P. Berlinguette1,2,3 1

Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T 1Z1, Canada.

2

Department of Chemical and Biological Engineering, The University of British Columbia, 2360 East Mall, Vancouver, British Columbia, V6Y 1Z3, Canada. 3

Stewart Blusson Quantum Matter Institute, The University of British Columbia, 2355 East Mall, Vancouver, British Columbia, V6T 1Z4, Canada.

ACS Paragon Plus Environment

Journal of the American Chemical Society 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 2 of 19

Abstract We report here the advantages of using a palladium membrane reactor to drive hydrogenation chemistry with electricity while bypassing the formation of gaseous H2. This technique uses a palladium membrane to physically separate the electrochemical and hydrogenation chemistry. As a result, hydrogenation can be performed electrochemically with protons but in any organic solvent. We have previously demonstrated the use of this device to couple two reactions. In this manuscript, we outline a series of experiments showing how hydrogenation in the palladium membrane reactor proceeds at faster reaction rates and with much higher voltage efficiency than hydrogenation at an electrode. Moreover, the organic reaction chemistry in the membrane reactor does not suffer from contamination, and solvent flexibility broadens the possible product distribution of the reaction.


1

Page 3 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Introduction The efficient conversion of renewable electricity into chemical products has the potential to play an important role in a sustainable energy economy.1,2 The electrolysis of water into dihydrogen (H2) holds particular promise in this regard, with commercial electrolyzers now capable of producing H2 selectively and efficiently at high current densities. Notwithstanding, there remain many technological and economic challenges for a hydrogen economy to be realized, including the handling, storage and transport of H2.3,4 It is against this backdrop that our program is interested in exploring alternative ways to use electricity to make value-added chemicals, but without making H2. One possible use for renewable electricity is to perform organic reactions at an electrode to enable the selective production of complex high-value products.5–7 Organic electrosynthesis offers many advantages beyond simply leveraging cheap electricity, including the ability to bypass the need for toxic redox reagents and the potential for high energy efficiency.6,8 However, there remain many substantial challenges that need to be considered for this chemistry to scale, including: (i) the separation of the starting material and product from the electrolyte;6 (ii) limited substrate scope when using an aqueous solution; and/or (iii) a high solution resistance when using an organic solvents. We are particularly intrigued by electrochemical hydrogenation (ECH), a class of organic electrosynthesis that uses electrolytic hydrogen directly for the formation of new C–H bonds.9–12 ECH is a cathodic electrosynthetic process where protons are reduced to hydrogen atoms at a catalyst surface that then react with unsaturated organic reactants.9 A powerful feature of this architecture is that hydrogen fugacity can be controlled by using an applied electrochemical potential rather than hydrogen pressure.13 Consequently, hydrogen sourced from water can be used to hydrogenate organic reagents without the use of H2 gas. However, there are many constraints associated with this electrosynthetic method. The electrolyte must be protic to provide a hydrogen source for the reaction, and thus an aqueous medium is generally used. This reaction medium limits the scope of available chemistry, and the use of organic co-solvents to increase the solubility will ultimately drive up the solution resistance ACS Paragon Plus Environment

2


Page 4 of 19

and thus demand higher reaction voltages. Moreover, the organic products need to be separated from the electrolyte. These collective factors have constrained the impact of ECH on the field of organic synthesis. We have previously demonstrated that a palladium membrane reactor, a device that uses electricity to drive the formation of value-added chemicals: (i) offers the ability to perform reaction chemistry in either organic or aqueous solvents; (ii) operates at low voltages and high current densities (i.e., fast reaction rates); and (iii) sources hydrogen from water. In our previous work, we used the palladium membrane reactor to couple two organic reactions together. In this work, we showcase how the hydrogenation reaction in a palladium membrane reactor (Fig. 1a) overcomes many of the challenges in organic electrosynthesis. This so-called “membrane reactor” facilitates organic electrochemistry, specifically hydrogenation reactions, by generating reduced hydrogen atoms on one side of a membrane and reducing an organic reactant with those hydrogen atoms on the other side of the membrane. Palladium works effectively for this purpose because monoatomic hydrogen atoms readily absorb and diffuse into the palladium lattice.14,15 In palladium membrane hydrogenation, protons are reduced at the surface of a thin palladium foil (which acts as both the cathode and membrane) to form surface-adsorbed hydrogen that diffuses through the palladium to react with unsaturated organic reactants on the opposing side of the foil.16–21 The palladium membrane therefore acts as: (i) an electrode for the electrochemical compartment; (ii) a catalyst and supply of reactive hydrogen for the hydrogenation compartment; and (iii) a physical barrier that prevents mixing of the electrolyte and solvents between the electrochemical and hydrogenation compartments.22–24 Hydrogenation can therefore be performed in a different solvent than the electrolyte, in contrast to hydrogenation directly an electrode. The electrolyte also does not dissolve the reactant, and can have a high ionic conductivity leading to lower voltages (Fig. 1b).


3

Page 5 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 1. a) Protons are reduced to surface adsorbed hydrogen which can permeate through a palladium membrane to react (Pd membrane hydrogenation) or react directly at the electrode surface (electrochemical hydrogenation); b) The separation of solvent and electrolyte enables a significant voltage savings for hydrogenation Our interest in the membrane reactor (Fig. 1a) is also inspired by the findings that gas-fed palladium membrane reactors (not shown),20,21 where the hydrogen that diffuses through the palladium membrane is derived from H2 rather than protons, yield faster rates of hydrogenation than cases where the organic reactant and H2 react at the same face of the metal substrate.25–27 These differences in reaction rates have been ascribed to the organic reactant and H2 not needing to compete for an exposed metal surface to bind to because H2 is adsorbed at the opposite side of the metal substrate. Moreover, subsurface hydrogen has been shown to be more energetic and accesses different orbital pathways for hydrogenation, and has been invoked to affect both the reaction rate and selectivity of hydrogenation reactions.28,29 In this work, we examine the advantages of the palladium membrane reactor over performing a hydrogenation reaction directly an electrode, including hydrogen permeation through the membrane rather than reaction at the same surface as the substrate, the use of any organic solvent without added electrolyte and the use of any electrolyte with a high ionic conductivity. We determine the effect of these advantages on reaction rate, selectivity, product purity and distribution, and operating voltage, all key elements to organic reactions at an electrode. ACS Paragon Plus Environment

4


Page 6 of 19

Results and Discussion The membrane reactor for this study was designed with three compartments: a compartment containing a 1 cm2 platinum mesh anode where water oxidation to oxygen gas occurs; a compartment for reducing these protons into surface-adsorbed hydrogen at a palladium cathode; and a chemical compartment for hydrogenation (Fig. 2a). A palladium membrane (geometric surface area = 1.22 cm2) separates the electrochemical and chemical compartments, and a Nafion membrane separates the electrochemical compartments containing the anode and cathode. The cell is configured in the same way for hydrogenation directly at the electrode (“ECH reactor”) but the chemical compartment remains empty (Fig. 2b). 35 mL of electrolyte or reaction solution was added to each compartment and a 0.05-M phenylacetylene reactant concentration was used for all reactions. Both reaction compartments remained open to air and a current was applied to the system, which leads to both hydrogenation as well as some hydrogen evolution on both the chemical and electrochemical sides of the membrane. The voltage at the working electrode was measured using a Ag/AgCl reference electrode. An additional layer of palladium black (~5 mg) was electrodeposited on the membrane to increase the catalytic surface area, with previous measurements estimating ~250× increase in electrochemical surface area with deposition.24 This layer faced the electrochemical and chemical compartments for the ECH and membrane reactors, respectively. Phenylacetylene was used as the prototypical reactant for all experiments in this manuscript because it can be solubilized in the protic conditions required for ECH. The hydrogenation of phenylacetylene is also mechanistically informative because it can yield an alkene (styrene) or undergo a successive hydrogenation step to form the corresponding alkane (ethylbenzene; see Scheme 1).


5

Page 7 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 2. Photographs of the (a) ECH and (b) membrane reactor. In both cases, the cell has electrolyte in the middle and right compartments, with a Nafion membrane separating the reductive (middle compartment) and oxidative (side compartment) half cells. A palladium membrane separates the middle and side compartments. For the membrane reactor, the organic substrate is dissolved in solvent in the chemical compartment and the Pd black catalyst faces the side electrochemical compartment. For the ECH reactor, the organic substrate is dissolved in the middle compartment and the Pd catalyst faces the middle compartment. (The chemical compartment is therefore not operative for the ECH reactor. A Pt mesh counter electrode and Ag/AgCl reference electrode is used for both setups.)

We ran hydrogenation reactions in the respective ECH and membrane reactors and found that the membrane reactor yielded faster rates of phenylacetylene hydrogenation in all cases. We used a 1:1


6


Page 8 of 19

MeOH:1 M HCl v/v% (denoted as MeOH/HCl) mixture as the electrolyte for the ECH reactor (Fig. 3a), and in the anodic, cathodic and chemical compartments of the membrane reactor (Fig. 3b) to maintain a reasonably low uncompensated resistance (~17-20 Ω) and sufficiently high reactant solubility for the reaction (i.e., 0.05 M). The reactions were performed at an applied current of 20 and 50 mA for 24 h. For both reactors, 0.95 and the best fits are found for reactions performed in organic solvents. 𝑃𝐴 + 2𝐻 → 𝑆 + 2𝐻 → 𝐸𝐵

Eq. 1

𝑑𝑃𝐴 = −𝑘1 [𝐻] 1 [𝑃𝐴] = −𝑘′1 [𝑃𝐴] 𝑑𝑡

Eq. 2

𝑑𝑆 = 𝑘1 [𝐻] 1 [𝑃𝐴] − 𝑘2 [𝐻] 1 [𝑆] = 𝑘′1 [𝑃𝐴] − 𝑘′2 [𝑆] 𝑑𝑡

Eq. 3

𝑑𝐸𝐵 = 𝑘2 [𝐻] 1 [𝑆] = 𝑘′2 [𝑆] 𝑑𝑡

Eq. 4


8


Page 10 of 19

Table 1. Reaction conditions and effective rate constants determined based on modeling first-order phenylacetylene and styrene hydrogenation kinetics Reaction conditions

*

Rate constants

Reactor

Current

Solvent

Electrolyte

k′1 mol L-1 s-1

k′2 mol L-1 s-1

R2*

ECH

20 mA

N/A

HCl/MeOH

0.05

1.18

0.95

Membrane

20 mA

HCl/MeOH

HCl/MeOH

0.09

3.00

0.98

ECH

50 mA

N/A

HCl/MeOH

0.07

5.49

0.993

Membrane

50 mA

HCl/MeOH

HCl/MeOH

0.19

3.63

0.99

Membrane

50 mA

MeOH

HCl/MeOH

0.48

0.78

0.99

Membrane

50 mA

H2O/MeOH

HCl/MeOH

0.21

2.41

0.983

Membrane

50 mA

HCl/MeOH

HCl

0.14

1.82

0.96

Membrane

50 mA

DCM

HCl/MeOH

0.55

0.21

0.999

2

R describes the goodness-of-fit of the model to the experimental data

At both 25 and 50 mA applied currents, k′1 for the ECH reactor was smaller than that of the membrane reactor. The effective rate constants for the ECH reactor were k′1 = 0.05 at 20 mA and 0.07 at 50 mA and for the membrane reactor were k′1 = 0.09 at 20 mA and 0.19 at 50 mA (Table 1). For both reactors, k′2 >> k′1 with the MeOH/HCl solvent, indicating that hydrogenation of the alkyne to the alkene is much slower than from the alkene to the alkane, and alkyne hydrogenation rate-limiting. The large k′2 value explains why very little styrene is detected: styrene is formed then quickly consumed to make the ethylbenzene product. The faster reaction rates for the membrane reactor, which is consistent with subsurface hydrogen being operative and/or a lack of competition between the reactants for adsorption sites, corroborates observations made for gas-fed palladium membrane systems that a membrane reactor enables faster reaction rates.25,26,30


9

Page 11 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Another important outcome of these experiments is that the ECH reactor yielded a significant quantity of impurities (e.g., methyl formate and formic acid) where the membrane reactor did not (Fig. S17). The ECH impurities are ostensibly a result of methanol oxidation and dimerization.32 The cathode is open to air and thus we postulate that methanol oxidation may occur in the cathodic compartment through a reaction with H2O2, a product formed by O2 reduction at the cathode. We also cannot preclude methanol oxidation product crossover through the Nafion membrane (which separates the anode and cathode) contaminating the hydrogenation products formed at the cathode.31 Reactions in the membrane reactor with the same solvent are not contaminated with these impurities (Fig. S17) because the electrochemically-formed side products are separated from the product by the palladium membrane. The ECH reactor requires an ionically conductive, protic electrolyte to provide a hydrogen source for hydrogenation, but any solvent can be used in the chemical compartment of the membrane reactor which can enable improved reaction rate and different product distributions. To demonstrate the utility of this feature, we replaced MeOH/HCl (Fig. 4a) with MeOH (Fig. 4b) in the chemical compartment of the membrane reactor. This change in solvent medium increased the reaction rate, an increase that is reflected in the difference in effective rate constants for MeOH/HCl (k′1 = 0.19) and MeOH (k′1 = 0.48, Fig. 4, Table 1). The product distribution was also significantly different for the two reactions: Only a trace amount of styrene was detected in the MeOH/HCl mixture, while ~ 30% styrene was produced over 2 h in MeOH before being consumed and producing ethylbenzene. The effective rate constants can also explain the difference in product distribution. k′1 5% styrene. The effective rate constant for styrene to ethylbenzene is almost an order of magnitude larger in HCl/MeOH (k′2 = 3.63) than in MeOH and DCM (k′2 = 0.78 in MeOH, 0.51 in DCM, Table 1). Scheme 1 demonstrates that hydrogenation reaction selectivity is dependent on the relative rates of alkene desorption to form alkene product and alkene hydrogenation to form alkane product.33 It is expected that higher H2 flux through the membrane with organic solvents would increase the rate of alkene hydrogenation relative to desorption and produce more alkane,34 but the opposite effect is seen here. An aqueous solvent with lower hydrogen flux yielded more alkane product. These results point to another effect dominating in an aqueous solvent, such as the solvent polarity. It has previously been demonstrated that, in alkyne hydrogenation, the rate of the second hydrogenation step (alkene to alkane) increases exponentially with a linear increase in solvent dielectric.35 This trend is consistent with our with the nearly order of magnitude larger k′2 values in high polarity aqueous solvents than in organic solvents (Table 1). It is hypothesized here that the higher polarity of the aqueous medium relative to MeOH and DCM increases the alkene hydrogenation rate relative to desorption, either through stabilization of the alkene hydrogenation transition state or unfavourable alkene solvation. Notwithstanding, the empirical results appear to rule out the formation of alkenes with the ECH reactor because of the high dielectric, protic electrolyte that is required for operation. From these results, we purport that the solvent flexibility of the membrane reactor may enable selective alkene formation whereas the ECH cannot.


13

Page 15 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Scheme 1. Mechanism of phenylacetylene hydrogenation shows how reaction selectivity is governed by the relative rates of alkene desorption and alkene hydrogenation.33

Finally, we found that a significant electrical energy savings is provided by the membrane reactor that is not available to the ECH reactor owing to the differences in solvent/electrolyte media. We were constrained to a MeOH/HCl electrolyte for the ECH reactor in order to solubilize the reactant, but there is substantial solution resistance associated with this solvent. A higher ion concentration is therefore needed to decrease the solution resistance and lower the overpotential for hydrogen absorption. For example, a voltage savings of ~ 1 V at the working electrode/cathode is provided when operating at 50 mA when using a 1–M HCl electrolyte relative to a MeOH/HCl electrolyte for both the ECH and membrane reactors (Fig. 6a). We measured the pH difference between these two electrolytes to ensure that voltage savings in the 1–M HCl electrolyte could not be attributed to differences in electrolyte pH. We found a 0.6 pH unit difference between the electrolytes, meaning only 35 mV (3.5%, 59 mV per pH unit) of the 1 V savings could be accounted for by pH. The differences in the two solvent systems (i.e., MeOH/HCl vs HCl) minimally changes the rates of reactions at 50 mA in the membrane reactor, despite operating at strikingly different voltages. The effective rate constants were k′1 = 0.19 and 0.15 for MeOH/HCl and HCl electrolytes, respectively, values that are still significantly larger than k′1 = 0.07 for the ECH reactor (Fig. 6b, Table 1). These findings highlight the ability for the electrochemical


14


Page 16 of 19

component of the membrane reactor to work in a completely aqueous medium to minimize the operating voltage without sacrificing reaction rates.

Figure 6. (a) Comparison of the voltages required to hydrogenate phenylacetylene, and (b) the corresponding rates of ethylbenzene formation, for the three indicated experimental designs. Kinetic fits are determined by finding the best fit for Eqs. 2-4 to experimental data.

Conclusions In this work, we have demonstrated that the use of a palladium membrane for hydrogenation results in faster reaction rates with fewer contaminating side products compared to hydrogenation at an electrode. Deviation from a protic solvent improves reaction rates and opens up new reactivity pathways. Additionally, separation of the electrolyte from the hydrogenation environment enables the use of a purely aqueous electrolyte, minimizing the voltage needed to perform reactions. This study ACS Paragon Plus Environment

15

Page 17 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


shows that palladium membrane hydrogenation can overcome many of the challenges of performing organic reactions at an electrode.

References

(1) Cook, T. R.; Dogutan, D. K.; Reece, S. Y.; Surendranath, Y.; Teets, T. S.; Nocera, D. G. Solar Energy Supply and Storage for the Legacy and Nonlegacy Worlds. Chem. Rev. 2010, 110, 6474– 6502. (2) Lewis, N. S.; Nocera, D. G. Powering the Planet: Chemical Challenges in Solar Energy Utilization. Proc. Natl. Acad. Sci. U. S. A. 2006, 103, 15729–15735. (3) Gupta, R. B. Hydrogen Fuel: Production, Transport, and Storage; CRC Press, 2008. (4) Chu, S.; Majumdar, A. Opportunities and Challenges for a Sustainable Energy Future. Nature 2012, 488, 294–303. (5) Yan, M.; Kawamata, Y.; Baran, P. S. Synthetic Organic Electrochemical Methods Since 2000: On the Verge of a Renaissance. Chem. Rev. 2017, 117, 13230–13319. (6) Cardoso, D. S. P.; Šljukić, B.; Santos, D. M. F.; Sequeira, C. A. C. Organic Electrosynthesis: From Laboratorial Practice to Industrial Applications. Org. Process Res. Dev. 2017, 21, 1213–1226. (7) Frontana-Uribe, B. A.; Daniel Little, R.; Ibanez, J. G.; Palma, A.; Vasquez-Medrano, R. Organic Electrosynthesis: A Promising Green Methodology in Organic Chemistry. Green Chem. 2010, 12, 2099–2119. (8) Horn, E. J.; Rosen, B. R.; Chen, Y.; Tang, J.; Chen, K.; Eastgate, M. D.; Baran, P. S. Scalable and Sustainable Electrochemical Allylic C-H Oxidation. Nature 2016, 533, 77–81. (9) Lessard, J. Electrocatalytic Hydrogenation. In Encyclopedia of Applied Electrochemistry; Kreysa, G., Ota, K.-I., Savinell, R. F., Eds.; Springer New York, 2014; pp 443–448. (10) Nilges, P.; Schröder, U. Electrochemistry for Biofuel Generation: Production of Furans by Electrocatalytic Hydrogenation of Furfurals. Energy Environ. Sci. 2013, 6, 2925–2931. (11) Chadderdon, X. H.; Chadderdon, D. J.; Matthiesen, J. E.; Qiu, Y.; Carraher, J. M.; Tessonnier, J.P.; Li, W. Mechanisms of Furfural Reduction on Metal Electrodes: Distinguishing Pathways for Selective Hydrogenation of Bioderived Oxygenates. J. Am. Chem. Soc. 2017, 139, 14120–14128. (12) Singh, N.; Song, Y.; Gutiérrez, O. Y.; Camaioni, D. M.; Campbell, C. T.; Lercher, J. A. Electrocatalytic Hydrogenation of Phenol over Platinum and Rhodium: Unexpected Temperature Effects Resolved. ACS Catal. 2016, 6, 7466–7470. (13) Maoka, T.; Enyo, M. Hydrogen Absorption by Palladium Electrode Polarized in Sulfuric Acid Solution Containing Surface Active substances—I. The Cathodic Region. Electrochim. Acta 1981, 26, 607–614. (14) Wicke, E.; Brodowsky, H.; Züchner, H. Hydrogen in Palladium and Palladium Alloys. In Hydrogen in Metals II; Topics in Applied Physics; Springer, Berlin, Heidelberg, 1978; pp 73–155. (15) Devanathan, M. A. V.; Stachurski, Z. The Adsorption and Diffusion of Electrolytic Hydrogen in Palladium. Proc. R. Soc. Lond. A Math. Phys. Sci. 1962, 270, 90–102. (16) Lewis, F. A.; Magennis, J. P.; McKee, S. G.; Ssebuwufu, P. J. M. Hydrogen Chemical Potentials and Diffusion Coefficients in Hydrogen Diffusion Membranes. Nature 1983, 306, 673. (17) Gryaznov, V. M. Hydrogen Permeable Palladium Membrane Catalysts. Platinum Metals Rev. 1986, 30, 68–72. (18) Gryaznov, V. Membrane Catalysis. Catal. Today 1999, 51, 391–395. (19) Ward, T. L.; Dao, T. Model of Hydrogen Permeation Behavior in Palladium Membranes. J. Memb. ACS Paragon Plus Environment

16


Page 18 of 19

Sci. 1999, 153, 211–231. (20) Dittmeyer, R.; Höllein, V.; Daub, K. Membrane Reactors for Hydrogenation and Dehydrogenation Processes Based on Supported Palladium. J. Mol. Catal. A Chem. 2001, 173, 135–184. (21) Dittmeyer, R.; Svajda, K.; Reif, M. A Review of Catalytic Membrane Layers for Gas/Liquid Reactions. Top. Catal. 2004, 29, 3–27. (22) Inoue, H.; Abe, T.; Iwakura, C. Successive Hydrogenation of Styrene at a Palladium Sheet Electrode Combined with Electrochemical Supply of Hydrogen. Chem. Commun. 1996, 0, 55–56. (23) Iwakura, C.; Yoshida, Y.; Inoue, H. A New Hydrogenation System of 4-Methylstyrene Using a Palladinized Palladium Sheet Electrode. J. Electroanal. Chem. 1997, 431, 43–45. (24) Sherbo, R. S.; Delima, R. S.; Chiykowski, V. A.; MacLeod, B. P.; Berlinguette, C. P. Complete Electron Economy by Pairing Electrolysis with Hydrogenation. Nat. Catal. 2018, 1, 501–507. (25) Shirai, M.; Arai, M. Hydrogenation of Furan with Hydrogen Atoms Permeating through a Palladium Membrane. Langmuir 1999, 15, 1577–1578. (26) Nagamoto, H.; Inoue, H. The Hydrogenation of 1,3-Butadiene over a Palladium Membrane. Bull. Chem. Soc. Jpn. 1986, 59, 3935–3939. (27) Ceyer, S. T. The Unique Chemistry of Hydrogen beneath the Surface: Catalytic Hydrogenation of Hydrocarbons. Acc. Chem. Res. 2001, 34, 737–744. (28) Johnson, A. D.; Daley, S. P.; Utz, A. L.; Ceyer, S. T. The Chemistry of Bulk Hydrogen: Reaction of Hydrogen Embedded in Nickel with Absorbed CH3. Science 1992, 257, 223–225. (29) Teschner, D.; Borsodi, J.; Wootsch, A.; Révay, Z.; Hävecker, M.; Knop-Gericke, A.; Jackson, S. D.; Schlögl, R. The Roles of Subsurface Carbon and Hydrogen in Palladium-Catalyzed Alkyne Hydrogenation. Science 2008, 320, 86–89. (30) Itoh, N.; Xu, W. C.; Sathe, A. M. Capability of Permeate Hydrogen through Palladium-Based Membranes for Acetylene Hydrogenation. Ind. Eng. Chem. Res. 1993, 32, 2614–2619. (31) Kho, B. K.; Bae, B.; Scibioh, M. A.; Lee, J.; Ha, H. Y. On the Consequences of Methanol Crossover in Passive Air-Breathing Direct Methanol Fuel Cells. J. Power Sources 2005, 142, 50– 55. (32) Iwasita, T. Electrocatalysis of Methanol Oxidation. Electrochim. Acta 2002, 47, 3663–3674. (33) Ulan, J. G.; Maier, W. F. Mechanism of 2-Hexyne Hydrogenation on Heterogeneous Palladium. J Mol Catal 1989, 54, 243–261. (34) Bond, G. C.; Wells, P. B. The Mechanism of the Hydrogenation of Unsaturated Hydrocarbons on Transition Metal Catalysts. In Advances in Catalysis; Eley, D. D., Pines, H., Weisz, P. B., Eds.; Academic Press, 1965; Vol. 15, pp 91–226. (35) Shutt, E.; Winterbottom, J. M. Heterogeneous Catalysis in the Liquid Phase. Platin. Met. Rev. 1971, 15, 94–99. Associated Content: Supporting Information The supporting information is available free of charge on the ACS Publications website: Experimental details, tables (Tables S1-S2) and figures (Figures S1-S36) Acknowledgements: The authors are grateful to the Canadian Natural Science and Engineering Research Council (RGPIN 337345-13), Canadian Foundation for Innovation (229288), Canadian Institute for Advanced Research (BSE-BERL-162173), and Canada Research Chairs for financial support. We thank Brian Ditchburn for fabricating the cells. We also thank Dr. Maria Ezhova, Mark Okon for access to the 850 MHz spectrometer and Dr. Yun Lung for help with GC-MS experiments.


17

Page 19 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


TOC:


18

Efficient electrocatalytic hydrogenation with a palladium membrane

Recommend Documents