Novel hybrids of graphitic carbon nitride sensitized with free-base meso-tetrakis(carboxyphenyl) porphyrins for efficient visible light photocatalytic hydrogen production

Silva, Eliana S. Da; Moura, Nuno M. M.; Neves, Maria G. P. M. S.; Coutinho, Ana; Prieto, Manuel; Silva, Cláudia G.; Faria, Joaquim L.

doi:10.1016/j.apcatb.2017.08.079

Cited by 138 publications

(61 citation statements)

References 74 publications

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“…[151] Acr + -Mes, QuPh + -NA and porphyrins were reported to act as efficient organic photocatalysts for H 2 evolution with dihydronicotinamide adenine dinucleotide (NADH) by use of metal nanoparticles as catalysts. [152][153][154][155][156][157][158][159] However,n oH 2 evolution occurred under visible light illumination (l > 340 nm) of a phthalate buffer dispersion containing QuPh + -NA@sAlMCM-41 as ap hotocatalyst, sodiumo xalatea sa ne lectrond onor and PtNPs as an H 2 -evolution catalyst (Figure 15 a&). [151] When K 2 PtCl 6 (0.050 mm)w as added to the reaction solution insteado fP tNPs as ap recursor of H 2 -evolution catalyst, H 2 was evolved continuouslya sshown in Figure 15 a( *).…”

Section: Redox Photocatalysis Of Rc Modelcompoundsmentioning

confidence: 99%

Immobilization of Molecular Catalysts for Enhanced Redox Catalysis

2018

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In the homogenous phase, redox catalysts are often deactivated by bimolecular reactions. For example, the charge‐separated state of photoredox catalysts decayed via bimolecular back electron transfer reactions between the charge‐separated molecules to decrease the lifetimes of the catalytically active species. When photoredox catalysts are immobilized on solid supports, the lifetime of the charge‐separated state was remarkably elongated to enhance the photocatalytic activity. Immobilization of photoredox catalysts on electrodes is required for photocurrent generation, leading to development of solar cells. Metal‐oxygen intermediates, which are active for oxidation of various substrates including water oxidation, are also deactivated via bimolecular reactions to produce inactive forms such as dinuclear metal bis‐μ‐oxo complexes. Immobilization of metal complex catalysts on solid supports prohibits the bimolecular deactivation, enhancing the catalytic activity and stability. This Review focuses on recent development of immobilization of both organic and inorganic molecular catalysts on various supports for enhancement of the catalytic activity, selectivity and stability in thermal and photoinduced redox reactions.

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Section: Redox Photocatalysis Of Rc Modelcompoundsmentioning

confidence: 99%

Immobilization of Molecular Catalysts for Enhanced Redox Catalysis

2018

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“…These peaks confirmed the successful preparation of NiTCPP. [49,50] In addition, it can be observed that the integrated system NiO/NiTCPP kept almost all the major peaks of NiTCPP and the characteristic peak of NiO at 510 cm −1 also existed, further confirming the combination of NiTCPP and NiO. All the above results proved that the integrated system of m-V O -NiO/ NiTCPP has been successfully prepared.…”

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confidence: 63%

Enhancing Charge Separation through Oxygen Vacancy‐Mediated Reverse Regulation Strategy Using Porphyrins as Model Molecules

Yin

Ning

Zhang

et al. 2020

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Up to now, substantial efforts have been devoted to enhancing charge separation by heterostructure construction, [7] cocatalyst loading, [8-10] element doping [11] and polarization, [12] among which coupling co-catalysts with semiconductors is a common and widespread method to improve the sluggish reaction kinetics [13] or influence the band bending of semiconductor to enhance charge separation. [14] However, the introduction of co-catalysts may cause unwanted light absorption and increase the possibility of recombination of photogenerated electrons and holes at the semiconductor/co-catalyst junction. [13,15] Therefore, developing highly efficient regulation methods is quite desirable and imperative for improving charge separation. Typically, electron-hole pairs generated by light absorption need to be separated and transferred to the surface of photoelectrodes to carry out redox reactions with adsorbed donor or acceptor molecules. As for photocathode, most previous studies focused on the electron transfer while much less attention has been paid to the regulation of holes in the construction of photocathodes, especially in PEC systems. In fact, compared with the recognized fast enough electron transfer process, the hole transport is a relative slow process, which determines the high charge recombination rate. [16-18] Xie et al. [16] reported that a homogeneous molecular co-catalyst influenced the hole transport process and therefore enhanced photocatalytic hydrogen production efficiency of the photocatalysis. Feldmann et al. [17] explored a redox couple to efficiently relay the hole from the semiconductor to the scavenger and lead to increased hydrogen production rate. These examples imply that modulating hole transfer is indeed a potentially effective method to enhance charge separation. Such modulation to facilitate charge separation also has been applied in inverted solar cells aiming at getting higher solar conversion efficiency. [19,20] Recently, defect engineering has been taken into consideration and demonstrated to be an effective method in tuning properties of electrocatalysts and photo(electro)catalysts. [21-23] Oxygen vacancy (V O), as one of the intrinsic defects in metal oxides, plays an essential role in improving the electronic Highly efficient charge separation has been demonstrated as one of the most significant steps playing decisive roles in enhancing the overall efficiency of photoelectrochemical (PEC) processes. In this study, by employing 5,10,15,20-tetrakis (4-carboxyphenyl) porphyrin-Ni (NiTCPP) as a prototype, an oxygen vacancy (Vo)-mediated reverse regulation strategy is proposed for tuning hole transfer, which in turn can accelerate the transport of electrons and thus enhancing charge separation. The optimal NiO/NiTCPP system exhibits much higher (≈40 times) photocurrent and longer (≈13 times) lifetime of charge carriers compared with those of pure NiTCPP. Furthermore, the electron transfer kinetic rate constant (K eff) is quantitatively determined by an efficient scanning photoelectroc...

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“…Stoichiometric evolution of hydrogen is evident from the start of the reaction, and there is a steady hydrogen increase throughout the entire run. TiO /β-CD has significantly higher H evolution rates of 5800 band (VB), and the the conduction band (CB) is high than the reduction 34,35 level of hydrogen. These bands respectively are easily to allow migration of photo-induced holes and electrons of photocatalytic water 36 splitting.…”

Section: Resultsmentioning

confidence: 99%

TiO /Cyclodextrin Hybrid Structure with Efficient Photocatalytic Water Splitting

Guo¹,

Shang²,

Zhao³

et al. 2018

ES Mater.Manuf.

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A novel TiO /β-cyclodextrin (TiO /β-CD) organic-inorganic hybrid nano-material with alveolate structure is fabricated using a facile one-step 2 2 strategy. The alveolate TiO /β-CD hybrid nano-material exhibits outstanding photocatalytic activity and recyclability on photocatalytic water 2-1 splitting. The production of H evolution of TiO /β-CD hybrid reaches to 5800 μmolg after 8 h without noble metal. Meanwhile, the 2 2 recyclability of the TiO /β-CD photocatalyst is found to be no obvious decrease with the H generation after third successive runs. The 2 2 formation of the oxygen defects occurred on coordinatively unsaturated Ti-sites by the introduction of β-CD at the outer surface of TiO could 2 be the predominant active species in the photocatalytic system. Due to the alveolate heterogeneous structure of TiO /β-CD hybrid play a role as 2 "channel" for photocatalytic activity. The channel can capture more electrons and light, provides a larger area for reaction. This work provides a promising approach to construct noble metal-free and more stabilized organic-inorganic nanocomposite photocatalysts applied in the photocatalytic water splitting. 2 2 μmol/g, which demonstrates it is quite effective to employ β-CD as

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Novel hybrids of graphitic carbon nitride sensitized with free-base meso-tetrakis(carboxyphenyl) porphyrins for efficient visible light photocatalytic hydrogen production

Cited by 138 publications

References 74 publications

Immobilization of Molecular Catalysts for Enhanced Redox Catalysis

Immobilization of Molecular Catalysts for Enhanced Redox Catalysis

Enhancing Charge Separation through Oxygen Vacancy‐Mediated Reverse Regulation Strategy Using Porphyrins as Model Molecules

TiO /Cyclodextrin Hybrid Structure with Efficient Photocatalytic Water Splitting

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