Charge transfer dynamics and catalytic performance of a covalently linked hybrid assembly comprising a functionalized cobalt tetraazamacrocyclic catalyst and CuInS₂/ZnS quantum dots for photochemical hydrogen production

Abstract

Covalently attaching the cobalt tetraazamacrocyclic complex to the surface of CuInS2/ZnS quantum dots enhanced the charge-separation efficiency and photocatalytic activity of the hybrid system.

Electrocatalytic reduction of protons to dihydrogen by the cobalt tetraazamacrocyclic complex [Co(N4H)Cl2]+: mechanism and benchmarking of performances

“…While Cat1 is becoming more and more popular as a molecular H 2 -evolving catalyst for the design of aqueous systems, it is increasingly important to advance the understanding of its H 2 evolution catalysis mechanism 13 and performance by providing insight into the catalytic steps involved. This is especially the case when considering structural modication 50 or molecular engineering 51 in order to either enhance catalytic activity or stability 16 or immobilise a catalytic centre for integration in photoelectrodes [7][8][9] or devices. In the societal context, both of these objectives are ultimately necessary to achieve industrial relevancy and technological maturity of hydrogen-producing electrolysers based on molecular catalysts made from earthabundant elements.…”

“…[1][2][3][4][5] Recently, the cobalt complex [Co(N 4 H)Cl 2 ] + (Cat1, Fig. 1) based on the tetraazamacrocyclic 2,12-dimethyl-3,7,11,17-tetraazabicyclo [11.3.1]heptadeca-1 (17),2,11,13,15-pentaene ligand, 6 described by Karn and Busch in 1966, has received increased interest [7][8][9] namely because this catalyst proves active and stable for the evolution of H 2 from fully aqueous solutions. [7][8][9][10][11][12][13][14][15][16][17] A study carried out under homogeneous conditions using chemical reductants or photochemical activation conrmed the superior activity of Cat1 in fully aqueous media, 18 and X-ray absorption spectroscopic monitoring of a homogeneous photocatalytic system for H 2 evolution based on Cat1 indicated an ECEC mechanism (E ¼ monoelectronic electrochemical reduction, C ¼ protonation step) starting from the bisaqua Co(II) complex.…”

Quantum Dots‐Based Photoelectrochemical Hydrogen Evolution from Water Splitting

“…Very recently, Mei Wang's group covalently linked [Co(CR) X 2 ] + to CuInS 2 /ZnS QDs, further improving the interfacial charge transfer between QDs and cocatalysts and suppressing the undesired back charge recombination process. [191] The introduction of plasmonic nanostructures with localized surface-plasmon resonances was found to enhance the STH efficiency effectively. Li's group [192] decorated CdTe QDs/TiO 2 with Ag/SiO 2 and related the enhanced STH efficiency results from the field enhancement effect because the silica shells excluded the impacts of the plasmon-induced "hot" electrons as well as the electronic interactions between QDs and Ag.…”

Spectroscopic Investigations Provide a Rationale for the Hydrogen-Evolving Activity of Dye-Sensitized Photocathodes Based on a Cobalt Tetraazamacrocyclic Catalyst

“…The superior activity and stability of the latter, compared to the cobalt diimine-dioxime catalyst, was previously reported for photocatalytic proton reduction under fully aqueous conditions. [28][29][30][31][32][33][34][35] In parallel, the dye structure was modified from the previously published T1-Co 16 with a cyclopenta[1,2-b:5,4-b']dithiophene (CPDT) bridge to bathochromically shift the absorption and increase the extinction coefficient in the visible region. 36,37 The alkyl chains introduced on the linker are intended (i) to limit dyad-dyad interactions and (ii) to prevent dyad desorption by forming a hydrophobic layer at the surface of the NiO film.…”