Dual Homogeneous and Heterogeneous Pathways in Photo- and Electrocatalytic Hydrogen Evolution with Nickel(II) Catalysts Bearing Tetradentate Macrocyclic Ligands

Chen, Lingjing; Chen, Gui; Leung, Chi‐Fai; Man, Wai‐Lun; Ko, Chi‐Chiu; Anxolabéhère‐Mallart, Elodie; Robert, Marc; Lau, Tai‐Chu

doi:10.1021/cs501534h

Cited by 74 publications

(45 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Zuschriften use of toxic, expensive,and fragile photosensitizers,aswell as organic co-solvents. [30][31][32][33][34] Although an impressive TON Ni was previously reported in ap hotocatalytic system using thiolcapped CdSe QDs and nickel ions,t his system utilizes toxic components and does not make use of aw ell-defined molecular catalyst. [35] Control experiments using either TCEP (0.1m,p H5)o r AA (0.1m,pH5)showed much lower photoactivity (Supporting Information, Figure S2).…”

Section: Angewandte Chemiementioning

confidence: 99%

Clean Donor Oxidation Enhances the H₂ Evolution Activity of a Carbon Quantum Dot–Molecular Catalyst Photosystem

et al. 2016

View full text Add to dashboard Cite

Carbon quantum dots (CQDs) are new-generation light absorbers for photocatalytic H2 evolution in aqueous solution, but the performance of CQD-molecular catalyst systems is currently limited by the decomposition of the molecular component. Clean oxidation of the electron donor by donor recycling prevents the formation of destructive radical species and non-innocent oxidation products. This approach allowed a CQD-molecular nickel bis(diphosphine) photocatalyst system to reach a benchmark lifetime of more than 5 days and a record turnover number of 1094±61 molH2 (molNi )(-1) for a defined synthetic molecular nickel catalyst in purely aqueous solution under AM1.5G solar irradiation.

show abstract

Section: Angewandte Chemiementioning

confidence: 99%

Clean Donor Oxidation Enhances the H₂ Evolution Activity of a Carbon Quantum Dot–Molecular Catalyst Photosystem

et al. 2016

View full text Add to dashboard Cite

show abstract

“…[8][9][10][11][12][13][14][15][16] Electrochemical reduction of protons is an effective and convenient process to convert electrical energy to chemical energy through generating H 2 . [17][18][19] This process is rapidly gaining attention as a vital paradigm for future energy conversion, storage and delivery. 20,21 In nature, hydrogenases catalyze the reversible reduction of protons with low overpotentials and high turnover frequencies up to 9000 s −1 .…”

Section: Introductionmentioning

confidence: 99%

Reactivity and Mechanism Studies of Hydrogen Evolution Catalyzed by Copper Corroles

et al. 2015

View full text Add to dashboard Cite

Several copper corrole complexes were synthesized, and their catalytic activities for hydrogen (H 2 ) evolution were examined. Our results showed that substituents at the meso positions of corrole macrocycles played significant roles in regulating the redox and thus the catalytic properties of copper corrole complexes: strong electron-withdrawing substituents can improve the catalysis for hydrogen evolution, while electron-donating substituents are not favored in this system. Copper complex of 5,15-pentafluorophenyl-10-(4-nitrophenyl)corrole (1) was shown to have the best electrocatalytic performance among copper corroles examined. Complex 1 can electrocatalyze H 2 evolution using trifluoroacetic acid (TFA) as the proton source in acetonitrile. In cyclic voltammetry, the value of i cat /i p = 303 (i cat is the catalytic current, i p is the one-electron peak current of 1 in the absence of acid) at scan rate 100 mV s −1 and 20 °C is remarkable. Electrochemical and spectroscopic measurements revealed that 1 has the desired stability in concentrated TFA acid solution and is unchanged by functioning as an electrocatalyst. Stopped-flow, spectroelectrochemistry and theoretical studies provided valuable insights into the mechanism of hydrogen evolution mediated by 1. Doubly reduced 1 is the catalytic active species that reacts with a proton to give the hydride intermediate for subsequent generation of H 2 .

show abstract

“…24 It has furthermore been shown in studies on cobalt and nickel complexes that were initially designed to function as molecular HER catalysts for electrochemical H2 evolution, but were eventually proven to produce metallic electrodeposits that were responsible for the observed catalysis. [32][33][34][35][36][37] The level of contamination in solutions that can be encountered in an electrochemical experiment is sometimes sufficient to produce electrodeposited catalytic species. 38,39 The central feature of mechanism III is the role of interfaces between dye molecules and loose, dye-free NiO particles within the mesoporous film that have poor electrical contact to the surrounding film (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

Origin of Photoelectrochemical Generation of Dihydrogen by a Dye-Sensitized Photocathode without an Intentionally Introduced Catalyst

et al. 2017

View full text Add to dashboard Cite

Dye-sensitized photocathodes have been observed on several occasions to sustain light-driven H 2 generation without intentionally introduced catalysts. Herein, plausible mechanisms addressing this phenomenon are probed by a combination of long-term photoelectrochemical measurements with concurrent gas chromatography, transient absorption spectroscopy, and inductively coupled mass spectrometry using a perylenemonoimide-sexithiophene-triphenylamine (PMI-6T-TPA) sensitized NiO electrode. The experimental evidence obtained discounts the possibility for direct reduction of hydrogen by the dye and demonstrates that the availability of interfaces between dye molecules and any electrically disconnected NiO particles exposed to the electrolyte solution is critical for photoelectrocatalytic H 2 generation. These interfaces are postulated to serve as photoactive sites for the formation of a hydrogen evolution catalyst, e.g., metallic nickel, which can accept photogenerated electrons from the excited dye molecules. The Ni 0 catalyst can form via photoelectroreduction of Ni 2+ , which has been found to slowly dissolve from the NiO support into the solutions during the photoelectrochemical measurements. Additionally, dependence of the H 2 generation rate on the anion within the electrolyte has been identified, with the highest rates of 35-40 nmol h -1 cm -2 achieved with acetate. The origin of this dependence remains unsolved at this stage but is clearly demonstrated to be not associated with the different rates of dissolution of NiO, the presence of other transition metal contaminants, nor electronic impacts of the anion on the NiO valence band. Overall, the results herein demonstrate that the effects of the chemical nature of the electrolyte, metallic nickel deposited from dissolved Ni 2+ , and availability of the interfaces between disconnected NiO and adsorbed dye should be considered when interpreting the photoelectrocatalytic performance of dye-sensitized photocathodes for dihydrogen evolution. × Our colleague, mentor and friend Prof. Leone Spiccia has passed away before this work could be published. Leone was an outstanding researcher and personality, and is sadly missed. ABSTRACTDye-sensitized photocathodes have been observed on several occasions to sustain light-driven H2 generation without intentionally-introduced catalysts. Herein, plausible mechanisms addressing this phenomenon are probed by a combination of long-term photo-electrochemical measurements with concurrent gas chromatography, transient absorption spectroscopy and inductively coupled mass spectrometry using a perelenmonoimid-sexithiophene-triphenylamine (PMI-6T-TPA) sensitized NiO electrode. The experimental evidence obtained discounts the possibility for direct reduction of hydrogen by the dye and demonstrates that the availability of interfaces between dye molecules and any electrically-disconnected NiO particles exposed to the electrolyte solution is critical for photo-electrocatalytic H2 generation. These interfaces are postulated to serve as photo-a...

show abstract

Dual Homogeneous and Heterogeneous Pathways in Photo- and Electrocatalytic Hydrogen Evolution with Nickel(II) Catalysts Bearing Tetradentate Macrocyclic Ligands

Cited by 74 publications

References 66 publications

Clean Donor Oxidation Enhances the H₂ Evolution Activity of a Carbon Quantum Dot–Molecular Catalyst Photosystem

Clean Donor Oxidation Enhances the H₂ Evolution Activity of a Carbon Quantum Dot–Molecular Catalyst Photosystem

Reactivity and Mechanism Studies of Hydrogen Evolution Catalyzed by Copper Corroles

Origin of Photoelectrochemical Generation of Dihydrogen by a Dye-Sensitized Photocathode without an Intentionally Introduced Catalyst

Contact Info

Product

Resources

About

Dual Homogeneous and Heterogeneous Pathways in Photo- and Electrocatalytic Hydrogen Evolution with Nickel(II) Catalysts Bearing Tetradentate Macrocyclic Ligands

Cited by 74 publications

References 66 publications

Clean Donor Oxidation Enhances the H2 Evolution Activity of a Carbon Quantum Dot–Molecular Catalyst Photosystem

Clean Donor Oxidation Enhances the H2 Evolution Activity of a Carbon Quantum Dot–Molecular Catalyst Photosystem

Reactivity and Mechanism Studies of Hydrogen Evolution Catalyzed by Copper Corroles

Origin of Photoelectrochemical Generation of Dihydrogen by a Dye-Sensitized Photocathode without an Intentionally Introduced Catalyst

Contact Info

Product

Resources

About

Clean Donor Oxidation Enhances the H₂ Evolution Activity of a Carbon Quantum Dot–Molecular Catalyst Photosystem

Clean Donor Oxidation Enhances the H₂ Evolution Activity of a Carbon Quantum Dot–Molecular Catalyst Photosystem