New Horizon in stabilization of single atoms on metal-oxide supports for CO2 reduction

Rich oxygen vacancies in confined heterostructured TiO2@In2S3 hybrid for boosting solar-driven CO2 reduction

Solar energy driving CO2 reduction is a potential strategy that not only mitigates the greenhouse effect caused by high CO2 level in atmosphere, but also yields carbon chemicals/fuels at the same time. Herein, a facile way to design the heterogeneous TiO2@In2S3 hollow structures possessing robust light harvesting in both ultraviolet and visible regions is proposed and exhibits a higher generation rate of 25.35 and 1.24 μmol·g-1·h-1 for photocatalytic CO2 reduction to CO and CH4, respectively. The excellent photocatalytic catalytic performance comes from i) the confined heterostructured TiO2@In2S3 possesses a suitable band structure and a broadband-light absorbing capacity for CO2 photoreduction, ii) the rich interfaces between nanosized TiO2 and In2S3 on the shell can significantly reduce the diffusion length of carriers and enhance the utilization efficiency of photogenerated electron-hole pairs, and iii) enriched surface oxygen vacancies can provide more active sites for CO2 adsorption.

Recent Progress and Opportunity of Metal Single-Atom Catalysts for Biomass Conversion Reactions

The conversion of lignocellulosic biomass into platform chemicals and fuels by metal single atoms is a new domain in solid catalysis research. Unlike the conventional catalysis route, single-atom catalysts (SACs) proliferate maximum utilization efficiency, high catalytic activity, and good selectivity to the desired product with an ultralow loading of the active sites. More strikingly, SACs show a unique cost-effective pathway for the conversion of complex sugar molecules to value-added chemicals in high yield and selectivity, which may be hindered by conventional metal nanoparticles. Primarily, SACs having adjustable active sites could be easily modified using sophisticated synthetic techniques based on their intended reactions. This review covers current research on the use of SACs with a strong emphasis on the fundamentals of catalyst design, and their distinctive activities in each type of reaction (hydrogenation, hydrogenolysis, hydrodeoxygenation, oxidation, and dehydrogenation). Furthermore, the fundamental insights into the superior actions of SACs within the opportunity and prospects for the industrial-scale synthesis of value-added products from the lignocelluloses are covered.

Transformation of a copper-based metal-organic polyhedron into a mixed linker MOF for CO2 capture

A new mixed linker metal-organic framework (MOF) has been synthesized from a copper-based metal-organic polyhedron (MOP-1) and 2,2'-bipyridine (2,2'-bipy). The CuMOF-Bipy with a formula of [Cu₂(2,2'-bpy)₂(m-BDC)₂]_n is comprised of a binuclear Cu(II) node coordinated to 2,2'-bipy, and isophthalic acid (m-BDC), which bridges to neighboring nodes. The crystal structure of CuMOF-Bipy consists of a stacked two-dimensional framework with the sql topology. CuMOF-Bipy was characterized by single-crystal X-ray diffraction (SC-XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and CO₂ sorption. CuMOF-Bipy was shown to have one-dimensional sinusoidal channels that allow diffusion of CO₂ but not N₂.

High selectivity of photocatalytic reduction of CO2 to CO based on terpyridine ligand supported CuI metal organic framework

In this work, a 4’-(4-cynaophenyl)-4,2’:6′,4-terpyridine supported CuI MOFs photocatalyst (CuIMOF) was applied to the photocatalytic CO2 reduction for the first time. The micro-structural and physicochemical properties of the CuIMOF were systematically studied by the powder X-ray diffraction (PXRD), Single crystal X-ray diffraction (SCXRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), UV-Vis diffuse spectroscopy (UV-vis DRS), ns-level photoluminescence spectra (ns-level PL), Ultraviolet photoelectron spectroscopy (UPS), and N2 adsorption-desorption test (BET-BJH). Moreover, the in situ diffuse reflectance infrared fourier transform spectroscopy (in situ DRIFTS) was applied to investigate the adsorption and reaction intermediates of photocatalytic CO2 reduction. As a result, CuIMOF exhibited good performance and outstanding selectivity toward photocatalytic reduction of CO2 to CO under full-spectrum and visible light illumination. Notably, 100% selective photocatalytic conversion of CO2 to CO was achieved. Thus, the study presents the high selectivity and CO2 reduction efficiency of CuIMOF as a potential family of photocatalysts.