Efficient photo-driven hydrogen evolution by binuclear nickel catalysts of different coordination in noble-metal-free systems

Abstract

Exploration of the complex Ni2(MBD)4 (MBD = 2-mercaptobenzimidazole) (C1) having different coordinated Ni atoms as a photocatalyst for hydrogen evolution is made. For comparison, the bimetallic Ni2(MBT)4 (MBT = 2-mercaptobenthiazole) (C2) complex with the same coordinated Ni atoms was synthesized. Both of the complexes have been successfully constructed for photo-induced hydrogen production using organic dyes as photosensitizers and triethanolamine (TEOA) as the effective electron donor by visible light (>400 nm) in acetonitrile-water solution. The time-dependence of H2 generation and DFT computational studies demonstrate that the complex C1 is more active than C2 for H2 evolution. The mechanisms of photocatalytic hydrogen generation for C1 and C2 involve different protonation sites resulting from the differences between the two structures.

Spectroscopic Characterisation of a Bio‐Inspired Ni‐Based Proton Reduction Catalyst Bearing a Pentadentate N2S3 Ligand with Improved Photocatalytic Activity

“…Under these conditions, catalytic proton reduction was observed for both catalysts, as evidenced by the detection of hydrogen gas by gas chromatography (Figure ). Although catalysts 1 and 2 show lower photocatalytic activity than other Ni catalysts reported in the literature, a clear difference in the photocatalytic activity was observed between the two complexes. Going from the tetradentate N 2 S 2 ligand in 2 to the pentadentate N 2 S 3 ligand in 1 improves the turnover frequency of the photocatalytic production of H 2 from 2.2 to 3.8 h −1 .…”

Nickel-based cocatalysts for photocatalytic hydrogen production

“…In fact, many kinds of Ni-based molecular complexes have been reported as excellent electrocatalysts for H 2 evolution and as catalysts for photochemical H 2 production in combination with molecular dyes [111,[136][137][138][139][140][141]. For example, Xu and co-workers reported the use of a nickel-thiolate complex, which was assembled from Ni(II) salt and 2-mecaptoethanol in one step in water, Source: Reprinted with permission from Ref.…”

Recent Advances in Heterogeneous Photocatalytic Decolorization of Synthetic Dyes

“…Since in tropical countries, sunshine is available in abundance; therefore, application of this oxidation technology using solar light can be a cost- and energy-effective detoxification technology. Furthermore, the limitations of the photocatalyst system can be addressed in terms of the tight range of pH in which the reaction proceeds, the requirement for recovering the precipitated catalyst after treatment, and the deactivation by some ion-complexing agents such as phosphate anions [289, 290]. …”