The immobilisation of electrocatalysts for CO2 reduction onto light harvesting semiconductors is proposed to be an important step towards developing more efficient CO2 reduction photoelectrodes. Here, we report a low cost nickel cyclam complex covalently anchored to a metal oxide surface. Using transient spectroscopy we validate the role of surface immobilisation on enhancing the rate of photoelectron transfer. Furthermore [Ni(1,4,8,11-tetraazacyclotetradecane-6-carboxylic acid)](2+) (2) is shown to be a very active electrocatalyst in solution.
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http://dx.doi.org/10.1039/c4cp04871g | DOI Listing |
Inorg Chem
August 2024
Department of Chemistry, Indian Institute of Technology, Kanjikode, Palakkad, Kerala 678623, India.
A deeper comprehension of the characteristics of metal-superoxide and metal-peroxide chemical species is imperative, considering their pivotal functions in oxygen transport, enzymatic activation, and catalytic oxygenations. O activation is mediated by the interconversion of superoxide and peroxide species. Even though there are multiple studies on metal-superoxide and -peroxide intermediates, robust examples of their interconversion processes are scarce synthetically.
View Article and Find Full Text PDFActa Crystallogr E Crystallogr Commun
September 2023
L. V. Pisarzhevskii Institute of Physical Chemistry of the National Academy of Sciences of Ukraine, Prospekt Nauki 31, 03028, Kiev, Ukraine.
The asymmetric units of the isostructural compounds (1,4,8,11-tetra-aza-cyclo-tetra-decane-κ )nickel(II) tetra-iodido-cadmate(II), [Ni(CHN)][CdI] (), and tri-iodido-1κ -μ-iodido-(1,4,8,11-tetra-aza-cyclo-tetra-decane-2κ )cad-mium(II)zinc(II), [CdZnI(CHN)] () (CHN = 1,4,8,11-tetra-aza-cyclo-tetra-decane, cyclam, ), consist of the centrosymmetric macrocyclic cation [()] [ = Ni or Zn] with the metal ion lying on a twofold screw axis, and the tetra-iodo-cadmate anion [CdI] located on the mirror plane. In , the anion acts as an uncoordinated counter-ion while in it is bound to the Zn atom one of the iodide atoms, thus forming an electroneutral heterobimetallic complex [Zn()(CdI)]. The Ni and Zn ions are coordinated in a square-planar manner by the four secondary N atoms of the macrocyclic ligand , which adopts the most energetically stable -III conformation.
View Article and Find Full Text PDFJ Am Chem Soc
July 2023
Department of Chemistry and Stephenson Institute for Renewable Energy, University of Liverpool, Liverpool L69 7ZF, United Kingdom.
Pulsed electrolysis can significantly improve carbon dioxide reduction on metal electrodes, but the effect of short (millisecond to seconds) voltage steps on molecular electrocatalysts is largely unstudied. In this work, we investigate the effect pulse electrolysis has on the selectivity and stability of the homogeneous electrocatalyst [Ni(cyclam)] at a carbon electrode. By tuning the potential and pulse duration, we achieve a significant improvement in CO Faradaic efficiencies (85%) after 3 h, double that of the system under potentiostatic conditions.
View Article and Find Full Text PDFJ Org Chem
December 2022
Inorganic Chemistry I, Ruhr-Universität Bochum, Universitätsstraße 150, Bochum 44801, Germany.
The tetradentate azamacrocycle cyclam (=1,4,8,11-tetraazacyclotetradecane) was studied profoundly for the coordination of transition metal ions, and the resulting complexes were investigated extensively for their catalytic performance in, e.g., O activation and electrocatalytic CO reduction.
View Article and Find Full Text PDFActa Crystallogr E Crystallogr Commun
November 2022
L. V. Pisarzhevskii Institute of Physical Chemistry of the National Academy of Sciences of Ukraine, Prospekt Nauki 31, Kyiv, 03028, Ukraine.
The asymmetric unit of -poly[[[(1,4,8,11-tetra-aza-cyclo-tetra-decane-κ , , , )nickel(II)]-μ-5-carb-oxy-benzene-1,3-di-carboxyl-ato-κ : ] octa-hydrate], {[Ni(CHO)(CHN)]·8HO} (), consists of a macrocyclic Ni cation, a carboxyl-ate dianion and eight highly disordered water mol-ecules of crystallization. The components of the compound -poly[[[(1,4,8,11-tetra-aza-cyclo-tetra-decane-κ , , , )nickel(II)]-μ-5-carb-oxy-benzene-1,3-di-carboxyl-ato-κ : ] monohydrate], {[Ni(CHO)(CHN)]·HO} (), are two crystallographically unique centrosymmetric macrocyclic dications, a carboxyl-ate dianion and one water mol-ecule of crystallization. In each compound, the metal ion is coordinated in the equatorial plane by the four secondary N atoms of the macrocyclic ligand, which adopts the most energetically stable -III conformation, and two mutually O atoms of the carboxyl-ate anions in a slightly tetra-gonally distorted -NiNO octa-hedral geometry.
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