The Difference Se Makes: A Bio‐Inspired Dppf‐Supported Nickel Selenolate Complex Boosts Dihydrogen Evolution with High Oxygen Tolerance

Abstract

Inspired by the metal active sites of [NiFeSe]-hydrogenases, a dppf-supported nickel(II) selenolate complex (dppf=1,1'-bis(diphenylphosphino)ferrocene) shows high catalytic activity for electrochemical proton reduction with a remarkable enzyme-like H evolution turnover frequency (TOF) of 7838 s under an Ar atmosphere, which markedly surpasses the activity of a dppf-supported nickel(II) thiolate analogue with a low TOF of 600 s . A combined study of electrochemical experiments and DFT calculations shed light on the catalytic process, suggesting that selenium atom as a bio-inspired proton relay plays a key role in proton exchange and enhancing catalytic activity of H production. For the first time, this type of Ni selenolate-containing electrocatalyst displays a high degree of O and H tolerance. Our results should encourage the development of the design of highly efficient oxygen-tolerant Ni selenolate molecular catalysts.

Electrocatalytic Hydrogen Evolution Catalyzed by 3,4‐Toluenedithiolate Nickel Complexes of Bis(diphenylphosphine)amine Ligand Containing An Azahydrophilic Group

“…On the basis of above-mentioned electrochemical observations and the previously studies, [20,21,23,39] a CEEC (where E and C correspond to one-electron reduction and protonation) reaction mechanism might be proposed for hydrogen production catalyzed by 1 and 2 in MeCN in the presence of TFA, as displayed in Scheme 2, which is theoretically consistent with the experimental data (see DFT calculations). The following experimental results support the CEEC mechanism: (a) The catalytic peak current is proportion to the square root of TFA concentration; (b) he catalytic peak is significantly positively shifted compared to the reduction potential of Ni II /Ni I ; (c) H 2 is produced in the presence of TFA at À 1.6 V in the controlled potential electrolysis.…”

“…The new reduction peaks markedly increase with increasing TFA concentration. Typically, such characteristic represents electrocatalytic proton reduction to form H 2 , [21,23,44,45] which is confirmed by the controlled potential electrolysis experiment and GC‐TCD analysis (see Figure S18). The controlled experiments of the direct reduction of TFA by the glassy carbon electrode occurs at potentials more negative than −2.0 V using TFA without 1 and 2 under similar experimental conditions (Figures S13 and S14).…”

“…Notably, diphosphine ligand is widely used in the design of complex catalysts for hydrogen revolution because of its significant advantage in terms of ease of modification to tune catalytic actives [15–19] . 1,1’‐Bis(diphenylphosphino)ferrocene (dppf), as a well‐known sterically restrictive ligand, has been used to synthesize dppf‐supported nickel complexes that perform hydrogen evolution catalysts with low overpotentials [20,21] . Meanwhile, Xie and co‐workers reported that dcpf‐supported nickel complexes containing O‐alkyldithiophosphate ligands, [(dcpf)Ni(S 2 P{O}OR)] (dcpf=1,1‐bis(dicyclohexylphosphino)ferrocene), present higher electrocatalytic performances for the reduction trifluoroacetic acid (TFA) to hydrogen with turnover frequencies of 1047–2545 s −1 [22] .…”

“…[15][16][17][18][19] 1,1'-Bis(diphenylphosphino)ferrocene (dppf), as a well-known sterically restrictive ligand, has been used to synthesize dppf-supported nickel complexes that perform hydrogen evolution catalysts with low overpotentials. [20,21] Meanwhile, Xie and co-workers reported that dcpf-supported nickel complexes containing O-alkyldithiophosphate ligands, [(dcpf)Ni(S 2 P{O}OR)] (dcpf = 1,1-bis (dicyclohexylphosphino)ferrocene), present higher electrocatalytic performances for the reduction trifluoroacetic acid (TFA) to hydrogen with turnover frequencies of 1047-2545 s À 1 . [22] In addition, bis(diphenylphosphine)amine (RN(PPh 2 ) 2 , PNP) has also been used in the fabrication of complex electrocatalysts for hydrogen evolution, such as [(RN(PPh 2 ) 2 )Ni(S 2 P{O}OR')], [18] [Fe 2 (μpdt)(CO) 4 {(μ-Ph 2 P) 2 NR], [19] [(RN(PPh 2 ) 2 )Ni(mnt)], [23] and [(RN-(PPh 2 ) 2 )Ni(bdt)] [24,25] (pdt = propylene-1,3-dithiolate, mnt = maleonitriledithiolate, and bdt = 1,2-benzenedithiolate).…”

Reversing the Activity Center in Doped Pd17Se15 to Achieve High Stability Toward the Electrochemical Hydrogen Evolution Reaction

“…Recently, some chalcogenide materials have been reported to exhibit a high degree of hydrogen evolution activity. − Most of them have reported chalcogen surface sites as the active center toward hydrogen adsorption . ZrS 2 , ZrSe 2 , and ZrSSe are theoretically predicted to have better HER activity .…”