Light-Harvesting Property from Self-Assembly of Cobalt Nanocluster Aggregates for Efficient Hydrogen Evolution

Abstract

Herein, we report the light-harvesting property (LHP) from a self-assembled cobalt nanoaggregate (S-CoNA) for an efficient hydrogen evolution. The syntheses of S-CoNAs were achieved using 3-mercaptopropylsulfonate (MPS) as the stabilizer, and the as-formed compound exhibits broad absorption at 407 and 496 nm which appears in the visible region that prompts us to investigate the photo-electrochemical studies. Interestingly, the as-prepared S-CoNAs achieved enhanced hydrogen energy production in the visible region. To know the mechanism of LHP from S-CoNAs and to examine the (M/L) ratios and varying the M/L contribution in detail, we further synthesized S-CoNAs in different metal to ligand ratios (M/ L). Out of the five different ratios, the M/L (1:4) ratio resulted in a maximum response of 15 mA cm −2 at 0.3 V applied potential (vs Ag/AgCl). Further, we performed electrochemical studies by tuning the potentials (0, 0.3 V) followed by illumination in the presence and absence of visible light. Furthermore, Fourier-transform infrared spectroscopy analysis before and after photo-electrochemical reaction resulted in a notable peak at 998 and 2115 cm −1 , respectively, which is attributed to a metal sulfur linkage via both the thiol (−SH) and sulfonate (−SO 3 H) terminals of MPS. The photo-electrochemical reaction which is observed after this effective stabilization for S-CoNAs via Co−S linkages was responsible for the hydrogen energy production.

Advances in the Electrocatalytic Hydrogen Evolution Reaction by Metal Nanoclusters‐based Materials

“…This article introduced several approaches that have been used to enhance the electrocatalytic activity of metal clusters and noticed that support is always required to stabilize them due to their high surface energy, though few noble-metal-based free-standing clusters have been reported. [197][198][199][200] Generally, the conductivity, the porous structure, the anchoring sites, the electron structure, and the overall stability of the support are important factors considered for electrocatalysis. We summarized MNCs with enhanced HER catalytic activity according to the corresponding supports.…”

Gold-like Thiolate-Protected Ultrasmall Cubic Copper Nanocluster-Based Metal–Organic Framework as a Selective Catalyst for Stepwise Synthesis of Unsymmetric Bistriazole by Click Reaction

“…The HRTEM and AFM results for the cubic CuMOFs suggest average sizes of ∼2–12 and ∼4–10 nm, respectively, which might have been formed by the particles of Cu networks with an average size of ∼4.78 nm as shown Scheme a. The plausible mechanism for the selective mono-click at CuMOFs was evaluated using vibrational spectroscopic studies, which suggest the existence of two terminals in CuMOF nanoclusters, i.e., at one terminal, Cu­(I) is coordinated with the sulfur group (Cu­(I)–S), and at the other terminal, Cu(0) is coordinated with sulfonate (Cu–O–SO–O – ); this observation is inconsistent with our earlier report . As the bifunctional bisazide approaches the CuMOF catalyst, at one terminal, the bifunctional bisazide approaches via core atoms of (Cu(0)–O–SO–O – ) of CuMOFs to form an electrostatic interaction with the azide, i.e., it is unable to catalyze the azide–alkyne reaction, and on the other terminal, the bifunctional bisazide approaches through (Cu­(I)–S) of CuMOFs that enables the azide–alkyne reaction that affords monotriazole 5a , which was confirmed using FTIR spectra, as shown in Scheme b, with the reactant as the starting material and the CuMOF catalyst and showing the intermediate step after 3 h, resulting in the mono-click product.…”

First‐principles investigation of electronic and optical properties of H‐doped FeS 2

“…The exploring the sustaining, clear and high effective energy is very urgent because of the global energy crisis and environmental pollution 1‐9 . Molecular hydrogen (H 2 ) is regarded as the attractive energy carrier compared to the conventional fossil fuel 10‐15 .…”