Metalloporphyrin-Decorated Titanium Dioxide Nanosheets for Efficient Photocatalytic Carbon Dioxide Reduction

Abstract

In photocatalysis, the most efficient way to separate photogenerated electron–hole pairs has been extensively studied. However, the methods to increase the quantities of free electrons are neglected. Herein, we used a self-assembly method to fabricate MTCPP/TiO2 composite materials with a series of metalloporphyrins (MTCPPs, M = Fe, Co, Zn) as sensitizers to modify TiO2 nanosheets. First, abundant carboxyl and hydroxyl on porphyrin were adsorbed by metal ions. Then, the remaining carboxyl and hydroxyl on porphyrin were anchored on the surface of TiO2 nanosheets. Finally, MTCPP/TiO2 was obtained by a layer-by-layer self-assembly process. MTCPP broadens the light response of TiO2 from ultraviolet light to visible light and enhances the CO2 adsorption ability. Moreover, metal ions coordinating with porphyrin regulate the electron density of the porphyrin ring and provide a stronger π feedback bond, which promote charge separation. Consequently, by optimizing the type of metal ion, the yield of ZnTCPP/TiO2 composites reached 109.33 μmol/(g h) of CO and 9.94 μmol/(g h) of CH4, which was more than 50 times that of pure TiO2. This study proposes a possible visible-light-induced CO2 reduction mechanism of metal-ion-based photocatalysis, which provides great insights into optimizing the designation of efficient photocatalysis.

Insight into the Sensing Behavior of DNA Probes Based on MOF–Nucleic Acid Interaction for Bioanalysis

“…Additionally, FTIR spectra were used to investigate the coordination reaction between FeTCPP and UiO-66. As shown in Figure 1E, the stretching vibration of Fe−N (996 cm −1 ) from porphyrin appears in the spectrum of FeTCPP⊂UIO-66, 30,31 and the redshift of carboxyl vibration peaks from 1690 to 1655 cm −1 is attributed to the transition of free porphyrin to carboxylation chelating functionality in the prepared MOF. 32 These results authenticated that FeTCPP has been connected with the Zr 6 cluster through steady chemical bonds.…”

2D Catalysts for CO2 Photoreduction: Discussing Structure Efficiency Strategies and Prospects for Scaled Production Based on Current Progress

“…In addition, metal ions coordinated with porphyrins modulate the electron density of the porphyrin rings, providing stronger π‐feedback bonds and facilitating charge separation. The CO yield of the finally obtained ZnTCPP/TiO 2 composite was 109.33 μmol g −1 h −1 and the CH 4 yield was 9.94 μmol g −1 h −1 , which was more than 50 times that of pure TiO 2 [53] …”

“…The CO yield of the finally obtained ZnTCPP/TiO 2 composite was 109.33 μmol g À 1 h À 1 and the CH 4 yield was 9.94 μmol g À 1 h À 1 , which was more than 50 times that of pure TiO 2 . [53] On this basis, the combination of noble metal nanoparticles and 2D TiO 2 nanosheets can further improve the performance of the composite for the photoreduction of CO 2 (Table 2).…”

Interfacial Chemical Bond–Enhanced Charge Polarization in CoTCPP/Bi12O17Br2‐Triggering Efficient CO2 Photoreduction

“…A peak with weaker absorbance at 537 nm is attributed to the Q band of CoTCPP associated to a 2u (π) to e* g (π) transition. [32,33] The B band and Q band show various degrees of redshift on account of that Bi 3þ with lone pairs of electrons in the outer layers as Lewis base provides electrons to CoTCPP leading a decrease in leap energy, which once again proves that electrons transfer from BOB to CoTCPP, resulting in localized electron enrichment at the Co atom of the CoTCPP. [33,34] X-ray photoelectron spectroscopy (XPS) was further carried to explore the surface atomic chemical state of BOB and CBOB-2.…”