Di-Chang Zhong

A Dinuclear Cobalt Cryptate as a Homogeneous Photocatalyst for Highly Selective and Efficient Visible-Light Driven CO2 Reduction to CO in CH3CN/H2O Solution

A dinuclear cobalt complex [Co2 (OH)L1 ](ClO4 )3 (1, L1 =N[(CH2 )2 NHCH2 (m-C6 H4 )CH2 NH(CH2 )2 ]3 N) displays high selectivity and efficiency for the photocatalytic reduction of CO2 to CO in CH3 CN/H2 O (v/v=4:1) under a 450 nm LED light irradiation, with a light intensity of 100 mW cm-2 . The selectivity reaches as high as 98 %, and the turnover numbers (TON) and turnover frequencies (TOF) reach as high as 16896 and 0.47 s-1 , respectively, with the calculated quantum yield of 0.04 %. Such high activity can be attributed to the synergistic catalysis effect between two CoII ions within 1, which is strongly supported by the results of control experiments and DFT calculations.

A Highly Selective and Robust Co(II)-Based Homogeneous Catalyst for Reduction of CO2 to CO in CH3CN/H2O Solution Driven by Visible Light

Visible-light driven reduction of CO2 into chemical fuels has attracted enormous interest in the production of sustainable energy and reversal of the global warming trend. The main challenge in this field is the development of efficient, selective, and economic photocatalysts. Herein, we report a Co(II)-based homogeneous catalyst, [Co(NTB)CH3CN](ClO4)2 (1, NTB = tris(benzimidazolyl-2-methyl)amine), which shows high selectivity and stability for the catalytic reduction of CO2 to CO in a water-containing system driven by visible light, with turnover number (TON) and turnover frequency (TOF) values of 1179 and 0.032 s-1, respectively, and selectivity to CO of 97%. The high catalytic activity of 1 for photochemical CO2-to-CO conversion is supported by the results of electrochemical investigations and DFT calculations.

Two Li–Zn Cluster-Based Metal–Organic Frameworks: Strong H2/CO2 Binding and High Selectivity to CO2

Two metal-organic frameworks (MOFs) {(Me2NH2)[ZnLi(PTCA)(H2O)]}n·n{3DMF·C4H8O2·4H2O} (1) and {(Me2NH2)[ZnLi(PTCA)]}n·n{3DMF·5H2O} (2) have been constructed from Li-Zn clusters and pyrene-1,3,6,8-tetracarboxylic acid (H4PTCA) under solvothermal conditions. Gas sorption measurements have revealed that the pore of desolvated 2 (2d) can strongly interact with H2 and CO2, with high H2 and CO2 adsorption heats of 15.3 and 51.9 kJ/mol, respectively. Furthermore, 2d can selectively adsorb CO2 over N2 and CH4, with high adsorption selectivity of CO2/N2 and CO2/CH4.

The synergistic catalysis effect within a dinuclear nickel complex for efficient and selective electrocatalytic reduction of CO2 to CO

Developing cheap and earth-abundant catalysts for an efficient and selective reduction of CO2 is a promising approach to cut down the increasing emissions of CO2 and obtain valuable fuels/chemicals simultaneously. Here, we present a dinuclear nickel complex, [Ni2L1](ClO4)4 (1, L1 = 1,2-bis((5,7-dimethyl-1,4,8,11-tetraazacyclotetradecan-6-yl)methyl)benzene), which shows an excellent performance for the electrocatalytic reduction of CO2 to CO, with a Faradaic efficiency of 95%, and turnover number (TON) and turnover frequency (TOF) values of 4.1 × 106 and 190.0 s−1, respectively. Electrochemical experiments and density functional theory (DFT) calculations revealed that the excellent catalytic performance of 1 is attributed to the synergistic catalysis effect between two Ni centers within 1.

Template-directed synthesis of sulphur doped NiCoFe layered double hydroxide porous nanosheets with enhanced electrocatalytic activity for the oxygen evolution reaction

The development of readily available, highly efficient and stable electrocatalysts for the oxygen evolution reaction (OER) is extremely significant to facilitate water splitting for the generation of clean hydrogen energy. Layered double hydroxides (LDHs) exhibit promising electrocatalytic performance for the OER. However, their electrical conductivity and active sites should be increased for the preparation of more effective OER electrocatalysts based on LDHs for large-scale applications. Herein, we demonstrate a facile and practical pathway for the hierarchical fabrication of three-dimensional (3D) porous sulphur incorporated NiCoFe LDH nanosheets (S-NiCoFe LDH) on carbon cloth (CC). The as-obtained hierarchically structured S-NiCoFe LDH electrode shows superb electrocatalytic activity and stability for the OER, requiring overpotentials as low as 206 mV and 258 mV to achieve current densities of 10 mA cm−2 and 100 mA cm−2 in 1.0 M KOH solution, respectively, making S-NiCoFe LDH one of the most efficient low-cost electrocatalysts for the OER. The enhanced electrocatalytic performance is attributed to the unique 3D hierarchical nanostructure and sulphur doping, which endow the self-supported S-NiCoFe LDH electrode with abundant active sites and superb electrical conductivity. The strategy expands the possibilities for boosting the catalytic activity of LDH-based OER electrocatalysts.

A Copper(II) Molecular Catalyst for Efficient and Selective Photochemical Reduction of CO2 to CO in a Water-Containing System

A catalyst developed from a CuII complex of (Et4 N)[Cu(pyN2Me2 )(HCO2 )]⋅0.5 CH3 OH⋅H2 O (1⋅0.5 CH3 OH⋅H2 O; pyN2Me2 =bis(2,6-dimethylphenyl)-2,6-pyridinedicarboxamidate(2-)) shows a high activity to catalyze the reduction reaction of CO2 to CO driven by visible light in 4:1 acetonitrile/water (v:v) using [Ru(phen)3 ](PF6 )2 as photosensitizer and TEOA as sacrificial reductant, with a high TON of 9900 and a high CO selectivity of 98 %. The results of isotope labeling experiment, durability tests and energy dispersive spectroscopy reveal that 1 is robust during the photocatalytic process.

Template-Directed Growth of Bimetallic Prussian Blue-Analogue Nanosheet Arrays and Their Derived Porous Metal Oxides for Oxygen Evolution Reaction

Coordination polymers (CPs) are ideal precursors for synthesizing porous catalysts. However, the direct thermolysis of CPs is prone to generate agglomerates, greatly reducing the electrical conductivity and active sites of their derived catalysts. The construction of well-ordered CP nanostructures is a promising strategy for alleviating the above issue, but it remains challenging. Here, a facile chemical etching approach is developed for the fabrication of well-aligned three-dimensional (3D) bimetallic Prussian blue-analogue nanosheet arrays. Impressively, the derived porous metal oxide (Fe-NiO) acts as a remarkable oxygen evolution reaction (OER) catalyst, which merely requires overpotentials as low as 218 and 270 mV to achieve 10 and 100 mA cm-2 in 1.0 m KOH aqueous solution, respectively. The excellent electrocatalytic performance of Fe-NiO is ascribed to the 3D porous nanosheet array architecture, which endows the bimetallic catalyst with abundant electrocatalytic active sites, enhanced surface permeability, and high electronic conductivity. It is expected that the proposed strategy can pave a new way for fabricating highly efficient electrocatalysts for energy storage and conversion.

Highly Efficient and Selective Visible-Light Driven CO2-to-CO Conversion by a Co(II) Homogeneous Catalyst in H2O/CH3CN Solution

The photochemical reduction of CO2 to chemical resources has displayed the promise to solve energy and environmental problems. To facilitate this reaction, a considerable challenge is to design not only highly efficient and selective, but also economic catalysts. In this study, we report a homogeneous catalyst, [CoL1(CH3CN)](ClO4)2 (1, L1=Tris[2‐(iso‐propylamino)ethyl]amine) which displays high activity and selectivity for CO2 reduction to CO driven by visible light in a water‐containing system, with turnover numbers (TONCO) and turnover frequencies (TOF), and CO selectivity values of 44800, 1.24 s−1 and 97 %, respectively. The excellent performances of 1 for the photocatalytic CO2‐to‐CO conversion is confirmed by control experiments and its catalytic mechanism is corroborated by DFT calculations.