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Photocatalytic reduction of CO 2 is a promising strategy to mitigate the effects of global warming by converting CO 2 into valuable energy-dense products. Silver bismuth iodide (SBI) is an attractive material owing to its tunable bandgap and favorable band-edge positions for efficient CO 2 photoreduction. In this study, SBI materials, including AgBi 2 I 7 , AgBiI 4 , Ag 2 BiI 5 , and Ag 3 BiI 6 are first synthesized, through gas-solid reaction by controlling the stoichiometric ratio of reactants. The X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) results revealed that the distance between Ag-I is proportional to the degree of Ag ions delocalization, which occupies the vacant sites. That greatly retards the charge recombination at vacant sites. In addition, the surface potential via photo-assisted Kelvin probe force measurements of various SBI catalysts shows that Ag 3 BiI 6 exhibits the highest surface potential change due to the rich delocalized Ag ions. This results in effective charge carrier transport and prevention of charge recombination at vacant sites. Taking the above advantages, the averaged CO and CH 4 production rates for Ag 3 BiI 6 achieved 0.23 and 0.10 µmol g -1  h -1 , respectively. The findings suggest that Ag 3 BiI 6 has a high potential as a novel photocatalyst for CO 2 reduction and sheds light on the possibility of solving environmental contamination and sustainable energy crises., (© 2024 The Authors. Advanced Science published by Wiley‐VCH GmbH.)

The synthesis and characterization of a linear two-coordinate Cr(II) amido complex, Cr{N( t Bu)Dipp} 2 (Dipp=2,6-diisopropylphenyl), from the reaction of 1 molar equivalent (equiv) of CrCl 2 and 2 equiv. of LiN( t Bu)Dipp is reported. Single-crystal X-ray diffractometry (SC-XRD) analysis revealed that it has a short Cr-N bond distance of 1.8878(9) Å, which could be attributed to the relatively less bulky nature of the amido ligand compared with reported systems. Furthermore, the oxidation reaction of the two-coordinate Cr(II) complex was explored. The oxidation reaction of Cr{N( t Bu)Dipp} 2 with the one-electron oxidants AgOTf and [FeCp 2 ][BAr F 4 ] (BAr F 4 - =[B{C 6 H 3 -3,5-(CF 3 ) 2 } 4 ] - ) afforded the trigonal planar three- and bent two-coordinate Cr(III) complexes Cr{N( t Bu)Dipp} 2 (OTf) and [Cr{N( t Bu)Dipp} 2 ][BAr F 4 ], respectively. The reaction of Cr{N( t Bu)Dipp} 2 with 1 equiv. of the organic azides AdN 3 (Ad=1-adamantyl) and PhN 3 afforded the three-coordinate Cr(IV) imido complexes Cr{N( t Bu)Dipp} 2 (NAd) and Cr{N( t Bu)Dipp} 2 (NPh), respectively. The reaction of Cr{N( t Bu)Dipp} 2 and two equiv. of Me 3 NO afforded the Cr(VI) dioxo complex Cr{N( t Bu)Dipp} 2 (O) 2 . The reaction of Cr{N( t Bu)Dipp} 2 with 1 equiv. of CyN=C=NCy resulted in the insertion of the carbodiimide into the Cr-N bond, with the formation of a three-coordinate Cr(II) complex. Finally, density functional theory (DFT) calculations were used to elucidate the electronic structure of these complexes., (© 2023 Wiley-VCH GmbH.)

A Z-scheme heterojunction with spatially separated cocatalysts is proposed for overcoming fundamental issues in photocatalytic water splitting, such as inefficient light absorption, charge recombination, and sluggish reaction kinetics. For efficient light absorption and interfacial charge separation, Z-scheme organic/inorganic heterojunction photocatalysts are synthesized by firmly immobilizing ultrathin g-C 3 N 4 on the surface of TiO 2 hollow spheres via electrostatic interactions. Additionally, two cocatalysts, Pt and IrO x , are spatially separated along the Z-scheme charge-transfer pathway to enhance surface charge separation and reaction kinetics. The as-prepared Pt/g-C 3 N 4 /TiO 2 /IrO x (PCTI) hollow sphere photocatalyst exhibits an exceptional H 2 evolution rate of 8.15 mmol h -1 g -1 and a remarkable apparent quantum yield of 24.3% at 330 nm in the presence of 0.5 wt% Pt and 1.2 wt% IrO x cocatalysts on g-C 3 N 4 and TiO 2 , respectively. Photoassisted Kelvin probe force microscopy is used to systematically analyze the Z-scheme charge-transfer mechanism within PCTI. Furthermore, the benefits of spatially separating cocatalysts in the PCTI system are methodically investigated in comparison to randomly depositing them. This work adequately demonstrates that the combination of a Z-scheme heterojunction and spatially separated cocatalysts can be a promising strategy for designing high-performance photocatalytic platforms for solar fuel production., (© 2022 Wiley-VCH GmbH.)