scholarly journals Tandem redox mediator/Ni(ii) trihalide complex photocycle for hydrogen evolution from HCl

2015 ◽  
Vol 6 (2) ◽  
pp. 917-922 ◽  
Author(s):  
Seung Jun Hwang ◽  
David C. Powers ◽  
Andrew G. Maher ◽  
Daniel G. Nocera
Keyword(s):  
Excited State ◽  
Transition Metal ◽  
Metal Complexes ◽  
Hydrogen Evolution ◽  
Transition Metal Complexes ◽  
Redox Mediator ◽  
Metal Catalyst ◽  
Nickel Metal ◽  
Excited State Lifetimes

The challenge that short excited state lifetimes of first-row transition metal complexes present to the photoactivation of M–X bonds has been overcome with a phosphine mediator coupled to a nickel metal catalyst.

First-row transition metal porphyrins for electrocatalytic hydrogen evolution — a SPP/JPP Young Investigator Award paper

2020 ◽  
Vol 24 (11n12) ◽  
pp. 1361-1371
Author(s):  
Haitao Lei ◽  
Yabo Wang ◽  
Qingxin Zhang ◽  
Rui Cao
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Hydrogen Evolution ◽  
Transition Metal Complexes ◽  
Catalytic Efficiency ◽  
Electrochemical Analysis ◽  
Metal Porphyrin ◽  
High Turnover ◽  
Faradaic Efficiency ◽  
Metal Porphyrins

A series of first-row transition metal complexes of tetrakis(pentafluorophenyl)porphyrin (1), denoted as 1-M (M [Formula: see text] Mn, Fe, Co, Ni, Cu, and Zn), were synthesized and examined as electrocatalysts for the hydrogen evolution reaction (HER). All these transition metal porphyrins were shown to be active for HER in acetonitrile using trifluoroacetic acid (TFA) as the proton source. The molecular nature and the stability of these metal porphyrins when functioning as HER catalysts were confirmed, and all catalysts gave Faradaic efficiency of >97% for H2 generation during bulk electrolysis. Importantly, by using 1-Cu, a remarkably high turnover frequency (TOF) of 48500 s[Formula: see text] 1-Cu the most efficient among this series of metal porphyrin catalysts. This TOF value also represents one of the highest values reported in the literature. In addition, electrochemical analysis demonstrated that catalytic HER mechanisms with these 1-M complexes are different. These results show that with the same porphyrin ligand, the change of metal ions will have significant impact on both catalytic efficiency and mechanism. This work for the first time provides direct comparison of electrocatalytic HER features of transition metal complexes of tetrakis(pentafluorophenyl)porphyrin under identical conditions, and will be valuable for future design and development of more efficient HER electrocatalysts of this series.

Excited-State Mixed Valence in Transition Metal Complexes

2006 ◽  
Vol 45 (17) ◽  
pp. 6556-6558 ◽  
Author(s):  
Edward A. Plummer ◽  
Jeffrey I. Zink
Keyword(s):  
Excited State ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Mixed Valence
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