Transition-Metal-Modified Vanadoborate Clusters as Stable and Efficient Photocatalysts for CO₂ Reduction

Abstract

Photocatalytic carbon dioxide reduction (CO2RR) is considered to be a promising sustainable and clean approach to solve environmental issues. Polyoxometalates (POMs), with advantages in fast, reversible, and stepwise multiple-electron transfer without changing their structures, have been promising catalysts in various redox reactions. However, their performance is often restricted by poor thermal or chemical stability. In this work, two transition-metal-modified vanadoborate clusters, [Co­(en)2]6­[V12B18O54­(OH)6]·17H2O (V12B18–Co) and [Ni­(en)2]6­[V12B18O54­(OH)6]·17H2O (V12B18–Ni), are reported for photocatalytic CO2 reduction. V12B18–Co and V12B18–Ni can preserve their structures to 200 and 250 °C, respectively, and remain stable in polar organic solvents and a wide range of pH solutions. Under visible-light irradiation, CO2 can be converted into syngas and HCOO– with V12B18–Co or V12B18–Ni as catalysts. The total amount of gaseous products and liquid products for V12B18–Co is up to 9.5 and 0.168 mmol g–1 h–1. Comparing with V12B18–Co, the yield of CO for V12B18–Ni declines by 1.8-fold, while that of HCOO– increases by 35%. The AQY of V12B18–Co and V12B18–Ni is 1.1% and 0.93%, respectively. These values are higher than most of the reported POM materials under similar conditions. The density functional theory (DFT) calculations illuminate the active site of CO2RR and the reduction mechanism. This work provides new insights into the design of stable, high-performance, and low-cost photocatalysts for CO2 reduction.

Proton-Conducting Vanadoborate with New [V10B26] Clusters

“…With the deepening of research, polyoxometalates (POMs) have been applied in many fields, especially in adsorption catalysis and ion exchange. − Vanadoborates are a growing family of POMs due to their diverse structures and physicochemical properties. − It is well-known that most of the B–O–V clusters in vanadoborates consist of vanadium–oxygen polyhedra [VO x ] ( x = 4–6) and boron–oxygen polyhedra [BO x ] (x = 3, 4). − Vanadium–oxygen and boron–oxygen polyhedra are further linked via corner sharing or edge sharing to form various clusters with different vanadium to boron ratios, including [V 12 B 32 ], [V 12 B 18 ], [V 12 B 16 ], [V 10 B 28 ], [V 10 B 24 ], [V 6 B 22 ], and [V 6 B 20 ] clusters. ,− Recently, transition-metal complexes have been introduced into vanadoborate structures, where they play a structure-directing role. , However, these complexes reported previously led to the formation of the three clusters V 12 B 18 , V 10 B 28 , and V 6 B 20 and there have been no reports about the V 10 B 26 system. − Therefore, it is meaningful to develop a vanadoborate built up from the new cluster through use of a metal complex as template.…”

Cd0.5Zn0.5S/CoWO4 Nanohybrids with a Twinning Homojunction and an Interfacial S-Scheme Heterojunction for Efficient Visible-Light-Induced Photocatalytic CO2 Reduction

“…At present, the utilization of fossil fuels leads to global energy shortage and climate warming, which greatly threaten the life of people. , CO 2 is the main conflagrant product of fossil fuel into reusable chemicals, so converting CO 2 can not only alleviate the problem of energy but also reduce the emission of CO 2 to ameliorate the global greenhouse effect. Referring to the procedure of plant photosynthesis to convert CO 2 into the available carbohydrates in nature, using photocatalytic technology with the renewable solar energy can transform CO 2 into value-added products.…”

Visible-Light-Driven Oxidation of Amines to Imines in Air Catalyzed by Polyoxometalate–Tris(bipyridine)ruthenium Hybrid Compounds

“…The HOMO and LUMO energy levels of [Ru­(bpy) 3 ]­Cl 2 are 1.24 and −1.25 eV according to the literature, respectively, and the HOMO energy level is further verified by the onset oxidation potential (1.36 V vs NHE) from cyclic voltammetry (Figure S8). , Based on the above experimental results, the energy band structures of [Ru­(bpy) 3 ]­Cl 2 and POMs in compounds 1 – 4 are shown in Figure c. In comparison with [Ru­(bpy) 3 ]­Cl 2 , the four kinds of POMs featured higher HOMO energy levels and lower LUMO energy levels.…”