Electrochemical and spectroscopic methods for evaluating molecular electrocatalysts

Nature Reviews Chemistry

Volumn 1, Issue , 2017, Pages

  Lee, Katherine J ^a   Elgrishi, Noémie ^a   Kandemir, Banu ^a   Dempsey, Jillian L ^a  

^a The University of North Carolina at Chapel Hill   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 85027129705     PISSN: None     EISSN: 23973358     Source Type: Journal    
DOI: 10.1038/s41570-017-0039     Document Type: Review

References (132)

1. Dempsey, J. L. et al. Molecular chemistry of consequence to renewable energy. Inorg. Chem. 44, 6879-6892 (2005).
2. Lewis, N. S., Nocera, D. G. Powering the planet: Chemical challenges in solar energy utilization. Proc. Natl Acad. Sci. USA 103, 15729-15735 (2006).
3. Benson, E. E., Kubiak, C. P., Sathrum, A. J., Smieja, J. M. Electrocatalytic and homogeneous approaches to conversion of CO2 to liquid fuels. Chem. Soc. Rev. 38, 89-99 (2009).
4. Kärkäs, M. D., Verho, O., Johnston, E. V., Åkermark, B. Artificial photosynthesis: Molecular systems for catalytic water oxidation. Chem. Rev. 114, 11863-12001 (2014).
5. McKone, J. R., Marinescu, S. C., Brunschwig, B. S., Winkler, J. R., Gray, H. B. Earth-abundant hydrogen evolution electrocatalysts. Chem. Sci. 5, 865-878 (2014).
6. Artero, V., Saveánt, J.-M. Toward the rational benchmarking of homogeneous H2-evolving catalysts. Energy Environ. Sci. 7, 3808-3814 (2014).
7. Costentin, C., Saveánt, J.-M. Multielectron, multistep molecular catalysis of electrochemical reactions: Benchmarking of homogeneous catalysts. ChemElectroChem 1, 1226-1236 (2014).
8. Elgrishi, N., McCarthy, B. D., Rountree, E. S., Dempsey, J. L. Reaction pathways of hydrogen-evolving electrocatalysts: Electrochemical and spectroscopic studies of proton-coupled electron transfer processes. ACS Catal. 6, 3644-3659 (2016).
9. Compton, R. G., Banks, C. E. Understanding Voltammetry 2nd edn (Imperial College Press, 2011).
10. Kissinger, P. T., Heineman, W. R. Cyclic voltammetry. J. Chem. Educ. 60, 702-706 (1983).
11. Mabbott, G. A. An introduction to cyclic voltammetry. J. Chem. Educ. 60, 697-702 (1983).
12. Bard, A. J., Faulkner, L. R. Electrochemical Methods: Fundamentals and Applications 2nd edn (Wiley, 2001).
13. Saveánt, J.-M., Su, K. B. Homogeneous redox catalysis of electrochemical reaction: Part VI. Zone diagram representation of the kinetic regimes. J. Electroanal. Chem. Interfacial Electrochem. 171, 341-349 (1984).
14. Saveánt, J.-M. Molecular catalysis of electrochemical reactions. Mechanistic aspects. Chem. Rev. 108, 2348-2378 (2008).
15. Saveánt, J.-M. Elements of Molecular and Biomolecular Electrochemistry (Wiley, 2006).
16. Rountree, E. S., McCarthy, B. D., Eisenhart, T. T., Dempsey, J. L. Evaluation of homogeneous electrocatalysts by cyclic voltammetry. Inorg. Chem. 53, 9983-10002 (2014).
17. Martin, D. J., McCarthy, B. D., Rountree, E. S., Dempsey, J. L. Qualitative extension of the EC zone diagram to a molecular catalyst for a multi-electron, multi-substrate electrochemical reaction. Dalton Trans. 45, 9970-9976 (2016).
18. Nadjo, L., Saveánt, J.-M., Su, K. B. Homogeneous redox catalysis of multielectron electrochemical reactions: Part II. Competition between homogeneous electron transfer and addition on the catalyst. J. Electroanal. Chem. Interfacial Electrochem. 196, 23-34 (1985).
19. Costentin, C., Drouet, S., Robert, M., Saveánt, J.-M. Turnover numbers, turnover frequencies, and overpotential in molecular catalysis of electrochemical reactions. Cyclic voltammetry and preparative-scale electrolysis. J. Am. Chem. Soc. 134, 11235-11242 (2012).
20. Rountree, E. S., Martin, D. J., McCarthy, B. D., Dempsey, J. L. Linear free energy relationships in the hydrogen evolution reaction: Kinetic analysis of a cobaloxime catalyst. ACS Catal. 6, 3326-3335 (2016).
21. Evans, D. H., O'Connell, K. M., Petersen, R. A., Kelly, M. J. Cyclic voltammetry. J. Chem. Educ. 60, 290-293 (1983).
22. Sampson, M. D., Kubiak, C. P. Manganese electrocatalysts with bulky bipyridine ligands: Utilizing Lewis acids to promote carbon dioxide reduction at low overpotentials. J. Am. Chem. Soc. 138, 1386-1393 (2016).
23. Sawyer, D. T., Sobkowiak, A., Roberts, J. L. Electrochemistry for Chemists 2nd edn (Wiley, 1995).
24. Izutsu, K. Electrochemistry in Nonaqueous Solutions (Wiley, 2003).
25. Zoski, C. G. (ed.) Handbook of electrochemistry (Elsevier, 2006).
26. Costentin, C., Saveánt, J.-M. Cyclic voltammetry of electrocatalytic films: Fast catalysis regimes. ChemElectroChem 2, 1774-1784 (2015).
27. Costentin, C., Saveánt, J.-M. Cyclic voltammetry analysis of electrocatalytic films. J. Phys. Chem. C 119, 12174-12182 (2015).
28. Costentin, C., Dridi, H., Saveánt, J.-M. Molecular catalysis of H2 evolution: Diagnosing heterolytic versus homolytic pathways. J. Am. Chem. Soc. 136, 13727-13734 (2014).
29. Rountree, E. S., Dempsey, J. L. Potential-dependent electrocatalytic pathways: Controlling reactivity with pKa for mechanistic investigation of a nickel-based hydrogen evolution catalyst. J. Am. Chem. Soc. 137, 13371-13380 (2015).
30. Rountree, E. S., Dempsey, J. L. Reactivity of proton sources with a nickel hydride complex in acetonitrile: Implications for the study of fuel-forming catalysts. Inorg. Chem. 55, 5079-5087 (2016).
31. Saveánt, J.-M., Vianello, E. Potential-sweep chronoamperometry: Kinetic currents for first-order chemical reaction parallel to electron-transfer process (catalytic currents). Electrochim. Acta 10, 905-920 (1965).
32. Delahay, P., Stiehl, G. L. Theory of catalytic polarographic currents. J. Am. Chem. Soc. 74, 3500-3505 (1952).
33. Bullock, R. M., Appel, A. M., Helm, M. L. Production of hydrogen by electrocatalysis: Making the H-H bond by combining protons and hydrides. Chem. Commun. 50, 3125-3143 (2014).
34. Thoi, V. S., Karunadasa, H. I., Surendranath, Y., Long, J. R., Chang, C. J. Electrochemical generation of hydrogen from acetic acid using a molecular molybdenum-oxo catalyst. Energy Environ. Sci. 5, 7762-7770 (2012).
35. Hartley, C. L., DiRisio, R. J., Screen, M. E., Mayer, K. J., McNamara, W. R. Iron polypyridyl complexes for photocatalytic hydrogen generation. Inorg. Chem. 55, 8865-8870 (2016).
36. Le Goff, A. et al. From hydrogenases to noble metal-free catalytic nanomaterials for H2 production and uptake. Science 326, 1384-1387 (2009).
37. Machan, C. W., Sampson, M. D., Kubiak, C. P. A molecular ruthenium electrocatalyst for the reduction of carbon dioxide to CO and formate. J. Am. Chem. Soc. 137, 8564-8571 (2015).
38. Kal, S., Filatov, A. S., Dinolfo, P. H. Electrocatalytic proton reduction by a dicobalt tetrakis-Schiff base macrocycle in nonaqueous electrolyte. Inorg. Chem. 53, 7137-7145 (2014).
39. Connor, G. P., Mayer, K. J., Tribble, C. S., McNamara, W. R. Hydrogen evolution catalyzed by an iron polypyridyl complex in aqueous solutions. Inorg. Chem. 53, 5408-5410 (2014).
40. Bigi, J. P., Hanna, T. E., Harman, W. H., Chang, A., Chang, C. J. Electrocatalytic reduction of protons to hydrogen by a water-compatible cobalt polypyridyl platform. Chem. Commun. 46, 958-960 (2010).
41. Liu, T., DuBois, D. L., Bullock, R. M. An iron complex with pendent amines as a molecular electrocatalyst for oxidation of hydrogen. Nat. Chem. 5, 228-233 (2013).
42. Helm, M. L., Stewart, M. P., Bullock, R. M., DuBois, M. R., DuBois, D. L. A synthetic nickel electrocatalyst with a turnover frequency above 100, 000 s1 for H2 production. Science 333, 863-866 (2011).
43. Costentin, C., Robert, M., Saveánt, J.-M. Catalysis of the electrochemical reduction of carbon dioxide. Chem. Soc. Rev. 42, 2423-2436 (2013).
44. Costentin, C., Drouet, S., Passard, G., Robert, M., Saveánt, J.-M. Proton-coupled electron transfer cleavage of heavy-atom bonds in electrocatalytic processes. Cleavage of a C-O bond in the catalyzed electrochemical reduction of CO2. J. Am. Chem. Soc. 135, 9023-9031 (2013).
45. Wiedner, E. S., Brown, H. J. S., Helm, M. L. Kinetic analysis of competitive electrocatalytic pathways: New insights into hydrogen production with nickel electrocatalysts. J. Am. Chem. Soc. 138, 604-616 (2016).
46. Gomez-Mingot, M. et al. Bioinspired tungsten dithiolene catalysts for hydrogen evolution: A combined electrochemical, photochemical, and computational study. J. Phys. Chem. B 119, 13524-13533 (2015).
47. Graham, D. J., Nocera, D. G. Electrocatalytic H2 evolution by proton-gated hangman iron porphyrins. Organometallics 33, 4994-5001 (2014).
48. Elgrishi, N., Chambers, M. B., Fontecave, M. Turning it off! Disfavouring hydrogen evolution to enhance selectivity for CO production during homogenous CO2 reduction by cobalt-terpyridine complexes. Chem. Sci. 6, 2522-2531 (2015).
49. Wiedner, E. S., Bullock, R. M. Electrochemical detection of transient cobalt hydride intermediates of electrocatalytic hydrogen production. J. Am. Chem. Soc. 138, 8309-8318 (2016).
50. Costentin, C., Drouet, S., Robert, M., Saveánt, J.-M. A. Local proton source enhances CO2 electroreduction to CO by a molecular Fe catalyst. Science 338, 90-94 (2012).
51. Costentin, C., Robert, M., Saveánt, J.-M., Tatin, A. Efficient and selective molecular catalyst for the CO2-to-CO electrochemical conversion in water. Proc. Natl Acad. Sci. USA 112, 6882-6886 (2015).
52. Costentin, C., Passard, G., Robert, M., Saveánt, J.-M. Pendant acid-base groups in molecular catalysts: H-bond promoters or proton relays Mechanisms of the conversion of CO2 to CO by electrogenerated iron(0) porphyrins bearing prepositioned phenol functionalities. J. Am. Chem. Soc. 136, 11821-11829 (2014).
53. Wasylenko, D. J., Rodríguez, C., Pegis, M. L., Mayer, J. M. Direct comparison of electrochemical and spectrochemical kinetics for catalytic oxygen reduction. J. Am. Chem. Soc. 136, 12544-12547 (2014).
54. Pegis, M. L. et al. Homogenous electrocatalytic oxygen reduction rates correlate with reaction overpotential in acidic organic solutions. ACS Cent. Sci. 2, 850-856 (2016).
55. Matheu, R., Neudeck, S., Meyer, F., Sala, X., Llobet, A. Foot of the wave analysis for mechanistic elucidation and benchmarking applications in molecular water oxidation catalysis. ChemSusChem 9, 3361-3369 (2016).
56. Bediako, D. K. et al. Role of pendant proton relays and proton-coupled electron transfer on the hydrogen evolution reaction by nickel hangman porphyrins. Proc. Natl Acad. Sci. USA 111, 15001-15006 (2014).
57. McCarthy, B. D., Donley, C. L., Dempsey, J. L. Electrode initiated proton-coupled electron transfer to promote degradation of a nickel(ii) coordination complex. Chem. Sci. 6, 2827-2834 (2015).
58. Elgrishi, N., Kurtz, D. A., Dempsey, J. L. Reaction parameters influencing cobalt hydride formation kinetics: Implications for benchmarking H2-evolution catalysts. J. Am. Chem. Soc. 139, 239-244 (2017).
59. Roubelakis, M. M., Bediako, D. K., Dogutan, D. K., Nocera, D. G. Proton-coupled electron transfer kinetics for the hydrogen evolution reaction of hangman porphyrins. Energy Environ. Sci. 5, 7737-7740 (2012).
60. Costentin, C., Passard, G., Robert, M., Saveánt, J.-M. Concertedness in proton-coupled electron transfer cleavages of carbon-metal bonds illustrated by the reduction of an alkyl cobalt porphyrin. Chem. Sci. 4, 819-823 (2013).
61. Rakowski DuBois, M., DuBois, D. L. The roles of the first and second coordination spheres in the design of molecular catalysts for H2 production and oxidation. Chem. Soc. Rev. 38, 62-72 (2009).
62. DuBois, D. L. Development of molecular electrocatalysts for energy storage. Inorg. Chem. 53, 3935-3960 (2014).
63. Connolly, P., Espenson, J. H. Cobalt-catalyzed evolution of molecular hydrogen. Inorg. Chem. 25, 2684-2688 (1986).
64. Dempsey, J. L., Brunschwig, B. S., Winkler, J. R., Gray, H. B. Hydrogen evolution catalyzed by cobaloximes. Acc. Chem. Res. 42, 1995-2004 (2009).
65. Solis, B. H., Hammes-Schiffer, S. Theoretical analysis of mechanistic pathways for hydrogen evolution catalyzed by cobaloximes. Inorg. Chem. 50, 11252-11262 (2011).
66. Dempsey, J. L., Winkler, J. R., Gray, H. B. Mechanism of H2 evolution from a photogenerated hydridocobaloxime. J. Am. Chem. Soc. 132, 16774-16776 (2010).
67. Dempsey, J. L., Winkler, J. R., Gray, H. B. Kinetics of electron transfer reactions of H2-evolving cobalt diglyoxime catalysts. J. Am. Chem. Soc. 132, 1060-1065 (2010).
68. Muckerman, J. T., Fujita, E. Theoretical studies of the mechanism of catalytic hydrogen production by a cobaloxime. Chem. Commun. 47, 12456-12458 (2011).
69. Hu, X., Brunschwig, B. S., Peters, J. C. Electrocatalytic hydrogen evolution at low overpotentials by cobalt macrocyclic glyoxime and tetraimine complexes. J. Am. Chem. Soc. 129, 8988-8998 (2007).
70. Razavet, M., Artero, V., Fontecave, M. Proton electroreduction catalyzed by cobaloximes: Functional models for hydrogenases. Inorg. Chem. 44, 4786-4795 (2005).
71. Hu, X., Cossairt, B. M., Brunschwig, B. S., Lewis, N. S., Peters, J. C. Electrocatalytic hydrogen evolution by cobalt difluoroboryl-diglyoximate complexes. Chem. Commun. 4723-4725 (2005).
72. Baffert, C., Artero, V., Fontecave, M. Cobaloximes as functional models for hydrogenases. 2. Proton electroreduction catalyzed by difluoroborylbis(dimethylglyoximato)cobalt(ii) complexes in organic media. Inorg. Chem. 46, 1817-1824 (2007).
73. Kaim, W., Fiedler, J. Spectroelectrochemistry: The best of two worlds. Chem. Soc. Rev. 38, 3373-3382 (2009).
74. Solis, B. H., Maher, A. G., Dogutan, D. K., Nocera, D. G., Hammes-Schiffer, S. Nickel phlorin intermediate formed by proton-coupled electron transfer in hydrogen evolution mechanism. Proc. Natl Acad. Sci. USA 113, 485-492 (2016).
75. Zavarine, I. S., Kubiak, C. P. A versatile variable temperature thin layer reflectance spectroelectrochemical cell. J. Electroanal. Chem. 495, 106-109 (2001).
76. Kondrachova, L. et al. Electrochemical investigations of platinum phenylethynyl complexes. J. Electroanal. Chem. 576, 287-294 (2005).
77. Flowers, P. A., Strickland, J. C. Easily constructed microscale spectroelectrochemical cell. Spectrosc. Lett. 43, 528-533 (2010).
78. Leblanc, N. et al. A fascinating multifaceted redox-active chelating ligand: Introducing the N, N-dimethyl-3, 3-biquinoxalinium "methylbiquinoxen" platform. Chem. Sci. 7, 3820-3828 (2016).
79. Quinton, C. et al. Redox-controlled fluorescence modulation (electrofluorochromism) in triphenylamine derivatives. RSC Adv. 4, 34332-34342 (2014).
80. Ibañez, D., Garoz-Ruiz, J., Heras, A., Colina, A. Simultaneous UV-visible absorption and Raman spectroelectrochemistry. Anal. Chem. 88, 8210-8217 (2016).
81. Dias, M. et al. Electrochemistry coupled to fluorescence spectroscopy: A new versatile approach. Electrochem. Commun. 6, 325-330 (2004).
82. Gora, M. et al. EPR and UV-vis spectroelectrochemical studies of diketopyrrolopyrroles disubstituted with alkylated thiophenes. Synth. Met. 216, 75-82 (2016).
83. Pluczyk, S. et al. UV-vis and EPR spectroelectrochemical investigations of triarylamine functionalized arylene bisimides. RSC Adv. 5, 7401-7412 (2015).
84. Machan, C. W., Sampson, M. D., Chabolla, S. A., Dang, T., Kubiak, C. P. Developing a mechanistic understanding of molecular electrocatalysts for CO2 reduction using infrared spectroelectrochemistry. Organometallics 33, 4550-4559 (2014).
85. Agnew, D. W. et al. Electrochemical properties and CO2-reduction ability of m-terphenyl isocyanide supported manganese tricarbonyl complexes. Inorg. Chem. 55, 12400-12408 (2016).
86. Cheung, P. L., Machan, C. W., Malkhasian, A. Y. S., Agarwal, J., Kubiak, C. P. Photocatalytic reduction of carbon dioxide to CO and HCO2H using fac-Mn(CN)(bpy)(CO)3. Inorg. Chem. 55, 3192-3198 (2016).
87. Froehlich, J. D., Kubiak, C. P. The homogeneous reduction of CO2 by [Ni(cyclam)]+: Increased catalytic rates with the addition of a CO scavenger. J. Am. Chem. Soc. 137, 3565-3573 (2015).
88. Machan, C. W. et al. Electrocatalytic reduction of carbon dioxide by Mn(CN)(2, 2-bipyridine)(CO)3: CN coordination alters mechanism. Inorg. Chem. 54, 8849-8856 (2015).
89. Stanton, C. J. III et al. Re(i) NHC complexes for electrocatalytic conversion of CO2. Inorg. Chem. 55, 3136-3144 (2016).
90. Huang, J., Korzeniewski, C. Temperature controlled cell for in situ infrared spectroelectrochemical measurements and its use in the study of CO isothermal desorption. J. Electroanal. Chem. 471, 146-150 (1999).
91. Liu, M., Zhang, Y., Chen, Y., Xie, Q., Yao, S. EQCM and in situ FTIR spectroelectrochemistry study on the electrochemical oxidation of TMB and the effect of large-sized anions. J. Electroanal. Chem. 622, 184-192 (2008).
92. Shaffer, D. W. et al. Reactivity of a series of isostructural cobalt pincer complexes with CO2, CO, and H+. Inorg. Chem. 53, 13031-13041 (2014).
93. Grice, K. A., Gu, N. X., Sampson, M. D., Kubiak, C. P. Carbon monoxide release catalysed by electron transfer: Electrochemical and spectroscopic investigations of [Re(bpy-R)(CO)4](OTf) complexes relevant to CO2 reduction. Dalton Trans. 42, 8498-8503 (2013).
94. Smieja, J. M. et al. Manganese as a substitute for rhenium in CO2 reduction catalysts: The importance of acids. Inorg. Chem. 52, 2484-2491 (2013).
95. Smieja, J. M., Kubiak, C. P. Re(bipy-tBu)(CO)3Cl-improved catalytic activity for reduction of carbon dioxide: IR-spectroelectrochemical and mechanistic studies. Inorg. Chem. 49, 9283-9289 (2010).
96. Lei, C., Hu, D., Ackerman, E. J. Single-molecule fluorescence spectroelectrochemistry of cresyl violet. Chem. Commun. 5490-5492 (2008).
97. Audebert, P., Miomandre, F. Electrofluorochromism: From molecular systems to set-up and display. Chem. Sci. 4, 575-584 (2013).
98. Miomandre, F., Pansu, R. B., Audibert, J. F., Guerlin, A., Mayer, C. R. Electrofluorochromism of a ruthenium complex investigated by time resolved TIRF microscopy coupled to an electrochemical cell. Electrochem. Commun. 20, 83-87 (2012).
99. Miomandre, F. et al. Coupling thin layer electrochemistry with epifluorescence microscopy: An expedient way of investigating electrofluorochromism of organic dyes. Electrochem. Commun. 13, 574-577 (2011).
100. Zhang, X., Zwanziger, J. W. Design and applications of an in situ electrochemical NMR cell. J. Magn. Reson. 208, 136-147 (2011).
101. Klod, S., Ziegs, F., Dunsch, L. In situ NMR spectroelectrochemistry of higher sensitivity by large scale electrodes. Anal. Chem. 81, 10262-10267 (2009).
102. Falck, D., Niessen, W. M. A. Solution-phase electrochemistry-nuclear magnetic resonance of small organic molecules. Trends Anal. Chem. 70, 31-39 (2015).
103. Bussy, U., Boujtita, M. Review of advances in coupling electrochemistry and liquid state NMR. Talanta 136, 155-160 (2015).
104. Boisseau, R., Bussy, U., Giraudeau, P., Boujtita, M. In situ ultrafast 2D NMR spectroelectrochemistry for real-time monitoring of redox reactions. Anal. Chem. 87, 372-375 (2015).
105. Wiltshire, R. J. K. et al. Channel-flow cell for X-ray absorption spectroelectrochemistry. J. Phys. Chem. C 113, 308-315 (2009).
106. Murray, P. R. et al. An in situ electrochemical cell for Q-and W-band EPR spectroscopy. J. Magn. Reson. 213, 206-209 (2011).
107. Tamski, M. A. et al. Quantitative measurements in electrochemical electron paramagnetic resonance. Electrochim. Acta 213, 802-810 (2016).
108. Christensen, P., Hamnett, A., Muir, A. V. G., Timney, J. A. An in situ infrared study of CO2 reduction catalysed by rhenium tricarbonyl bipyridyl derivatives. J. Chem. Soc. Dalton Trans. 1455-1463 (1992).
109. Vollmer, M. V. et al. Synthesis, spectroscopy, and electrochemistry of (-diimine)M(CO)3Br, M = Mn, Re, complexes: Ligands isoelectronic to bipyridyl show differences in CO2 reduction. Organometallics 34, 3-12 (2015).
110. Machan, C. W., Kubiak, C. P. Electrocatalytic reduction of carbon dioxide with Mn(terpyridine) carbonyl complexes. Dalton Trans. 45, 17179-17186 (2016).
111. Jones, L. H. Vibrational spectrum of nickel carbonyl. J. Chem. Phys. 28, 1215-1219 (1958).
112. Payne, J. D., Murr, N. E. Pathways for reduction of nickelocene under CO. J. Chem. Soc. Chem. Commun. 1137-1138 (1984).
113. Bourrez, M., Steinmetz, R., Ott, S., Gloaguen, F., Hammarström, L. Concerted proton-coupled electron transfer from a metal-hydride complex. Nat. Chem. 7, 140-145 (2015).
114. Gagliardi, C. J., Murphy, C. F., Binstead, R. A., Thorp, H. H., Meyer, T. J. Concerted electron proton transfer (EPT) in the oxidation of cysteine. J. Phys. Chem. C 119, 7028-7038 (2015).
115. Braten, M. N., Gamelin, D. R., Mayer, J. M. Reaction dynamics of proton-coupled electron transfer from reduced ZnO nanocrystals. ACS Nano 9, 10258-10267 (2015).
116. Symes, M. D., Surendranath, Y., Lutterman, D. A., Nocera, D. G. Bidirectional and unidirectional PCET in a molecular model of a cobalt-based oxygen-evolving catalyst. J. Am. Chem. Soc. 133, 5174-5177 (2011).
117. Petek, M., Neal, T. E., McNeely, R. L., Murray, R. W. Comparative spectroelectrochemical, stopped-flow kinetic, and polarographic study of the titanium(iii)-hydroxylamine reaction. Anal. Chem. 45, 32-38 (1973).
118. Kilgore, U. J. et al. Studies of a series of [Ni(PR2NPh2)2(CH3CN)]2+ complexes as electrocatalysts for H2 production: Substituent variation at the phosphorus atom of the P2N2 ligand. Inorg. Chem. 50, 10908-10918 (2011).
119. Ho, M.-H. et al. Ab initio-based kinetic modeling for the design of molecular catalysts: The case of H2 production electrocatalysts. ACS Catal. 5, 5436-5452 (2015).
120. Wiese, S., Kilgore, U. J., DuBois, D. L., Bullock, R. M. [Ni(PMe2NPh2)2](BF4)2 as an electrocatalyst for H2 production. ACS Catal. 2, 720-727 (2012).
121. Wiedner, E. S., Helm, M. L. Comparison of [Ni(PPh2NPh2)2(CH3CN)]2+ and [Pd(PPh2NPh2)2]2+ as electrocatalysts for H2 production. Organometallics 33, 4617-4620 (2014).
122. Rodenberg, A. et al. Mechanism of photocatalytic hydrogen generation by a polypyridyl-based cobalt catalyst in aqueous solution. Inorg. Chem. 54, 646-657 (2015).
123. Mirmohades, M. et al. Direct observation of key catalytic intermediates in a photoinduced proton reduction cycle with a diiron carbonyl complex. J. Am. Chem. Soc. 136, 17366-17369 (2014).
124. Lewandowska-Andralojc, A. et al. Mechanistic studies of hydrogen evolution in aqueous solution catalyzed by a tertpyridine-amine cobalt complex. Inorg. Chem. 54, 4310-4321 (2015).
125. Moonshiram, D. et al. Tracking the structural and electronic configurations of a cobalt proton reduction catalyst in water. J. Am. Chem. Soc. 138, 10586-10596 (2016).
126. Greene, B. L., Wu, C.-H., McTernan, P. M., Adams, M. W. W., Dyer, R. B. Proton-coupled electron transfer dynamics in the catalytic mechanism of a [NiFe]-hydrogenase. J. Am. Chem. Soc. 137, 4558-4566 (2015).
127. Grills, D. C. et al. Electrocatalytic CO2 reduction with a homogeneous catalyst in ionic liquid: High catalytic activity at low overpotential. J. Phys. Chem. Lett. 5, 2033-2038 (2014).
128. Kardash, D., Huang, J., Korzeniewski, C. A jacketed cell for infrared spectroelectrochemistry at constant above ambient temperatures. J. Electroanal. Chem. 476, 95-100 (1999).
129. Geskes, C., Heinze, J. A spectroelectrochemical cell for measurements in highly purified solvents. J. Electroanal. Chem. 418, 167-173 (1996).
130. Salbeck, J. An electrochemical cell for simultaneous electrochemical and spectroelectrochemical measurements under semi-infinite diffusion conditions and thin-layer conditions. J. Electroanal. Chem. 340, 169-195 (1992).
131. Shaw, M. J. et al. Fiber-optic infrared reflectance spectroelectrochemistry: Isomerization of a manganese pyranyl complex. J. Electroanal. Chem. 534, 47-53 (2002).
132. Paengnakorn, P. et al. Infrared spectroscopy of the nitrogenase MoFe protein under electrochemical control: Potential-triggered CO binding. Chem. Sci. 8, 1500-1505 (2017).