Facile synthesis of g-C3N4(0.94)/CeO2(0.05)/Fe3O4(0.01) nanosheets for DFT supported visible photocatalysis of 2-Chlorophenol

Wang

ACS Appl. Mater. Interfaces

et al. 2020

Highly selective catalytic hydrogenation of alkynes to alkenes is a highly important reaction owing to its industrial and commercial application. Specifically, semihydrogenation of terminal alkynes has been more challenging than internal alkenes even using Lindlar catalysts. Also, the high reduction degree state metal-supported catalysts like Pd0/C, Pt0/C, and Ru0/C have been well-known to be used widely in hydrogenation due to their super activity. However, charcoal can absorb a large amount of water; Pd/C with 50% water is convenient on a large-scale synthesis. Charcoal generally bears oxygen groups on its surface, which are responsible for low selectivity and undesired products. Even typically, only 10–60% of the Pd metal atoms are exposed, they still suffer from poor stability in acids owing to leaching. Herein, we intend to design active and stable metal catalysts with features as the following to avoid leaching: having strong interaction with the support and coordinatively unsaturated metal sites or low valence state metals physically isolated from the acid environment. Herein, a highly efficient semihydrogenation of terminal alkynes to produce alkenes has been realized using a heterogeneous Pd(II)/POP-GIEC catalyst, imine-linked, crystalline, and porous organic polymer supporter modified by coordination of Pd(OAc)2 to its walls under mild conditions. Surprisingly, for the first time, modified POP-supported low reduction degree PdII catalysts were synthesized efficiently, and they were successfully used in semihydrogenation of terminal alkynes. The substrate scope was studied and included both unfunctionalized as well as functionalized substituents on the para, ortho, and meta position of aromatic alkynes. The substrate having a substituent with the functionality of fluoro protected at the meta position was semihydrogenated with a high alkyne conversion of 100% and olefin selectivity (up to 99%).

Section: Results and Discussionmentioning

confidence: 92%

The Immobilization of Pd(II) on Porous Organic Polymers for Semihydrogenation of Terminal Alkynes

Wang

ACS Appl. Mater. Interfaces

et al. 2020

“…Figure 1 c shows Raman spectra of the g-C 3 N 4 and X5 samples. The characteristic Raman bands of the g-C 3 N 4 phase can be identified at 220, 262, 311, 350, 480, and 708 cm −1 45 . The X5 sample shows the bands at 221, ~ 294, ~ 410, ~ 498, and ~ 607 cm −1 for the α-Fe 2 O 3 phase and 370, 520, and 670 cm −1 for the Fe 3 O 4 phase 46 , in addition to the bands related to the g-C 3 N 4 phase.…”

Section: Resultsmentioning

confidence: 96%

Effects of iron oxide contents on photocatalytic performance of nanocomposites based on g-C3N4

Afkari

Masoudpanah

Hasheminiasari

et al. 2023

Sci Rep

Abstractα-Fe2O3/Fe3O4/g-C3N4 nanocomposites were prepared in-situ by solution combustion as magnetically separable photocatalysts using ferric nitrate as oxidant, glycine as organic fuel, and g-C3N4. The effects of various amounts of iron oxides, on the magnetic, optical, and photocatalytic properties were explored by different characterization methods. The magnetite (Fe3O4) phase as ferrimagnetic material disappeared with the increase in ferric nitrate contents, leading to the decrease of magnetic properties. The bandgap energy decreased from 2.8 to 1.6 eV with the increase of the hematite (α-Fe2O3) phase.The photocatalytic results showed that the type and amount of iron oxides had a significant effect on the decolorization of methylene blue, rhodamine B and methyl orange dyes under visible-light irradiation. The activity of the nanocomposite sample containing 37 wt. % iron oxides was more effective than that of the pristine g-C3N4 sample to photodegrade the methylene blue, rhodamine B and methyl orange, respectively. Moreover, the nanocomposites exhibited a higher photocurrent density than that of the pristine g-C3N4, mainly due to their lower charge recombination rate.

“…It is challenging to mimic natural solar-driven systems due to the high cost and unavailability of specific experimental requirements. [117] Therefore, it is essential to utilize computational expertise to design various morphologies, adding metal and non-metal dopants, [211] creating structural defects, [212,213] and mimicking the hybrid of C 3 N 4 with suitable organic and inorganic moieties. The hybrid DFT and MD models could be helpful to predict the optoelectrical properties, density of states (DOS), HOMO/LUMO, thermodynamic efficiencies, charge densities, etc.…”

Section: Future Perspectives (A) the Theoretical And Computational Mo...mentioning

confidence: 99%

Photocatalytic Water‐Splitting by Organic Conjugated Polymers: Opportunities and Challenges

Mansha

Ahmad

Khan

et al. 2022

The Chemical Record

The future challenges associated with the shortage of fossil fuels and their current environmental impacts intrigued the researchers to look for alternative ways of generating green energy. Solar‐driven water splitting into oxygen and hydrogen is one of those advanced strategies. Researchers have studied various semiconductor materials to achieve potential results. However, it encountered multiple challenges such as high cost, low photostability and efficiency, and required multistep modifications. The conjugated polymers (CPs) have emerged as promising alternatives for conventional inorganic semiconductors. The CPs offer low cost, sufficient light absorption efficiency, excellent photo and chemical stability, and molecular optoelectronic tunable characteristics. Furthermore, organic CPs also present higher flexibility to tune the basic framework of the backbone of the polymers, amendments in the sidechain to incorporate desired functionalities, and much‐needed porosity to serve better for photocatalytic applications. This review article summarizes the recent advancements made in visible‐light‐driven water splitting covering the aspects of synthetic strategies and experimental parameters employed for water splitting reactions with special emphasis on conjugated polymers such as linear CPs, planarized CPs, graphitic carbon nitride (g‐C3N4), conjugated microporous polymers (CMPs), covalent organic frameworks (COFs), and conjugated polymer‐based nanocomposites (CPNCs). The current challenges and future prospects have also been described briefly.