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Though bismuth vanadate (BiVO 4) exhibits a promising potential as a semiconductor photoanode toward photoelectrochemical (PEC) water oxidation, its PEC performance is still limited by the poor charge carrier transport and sluggish oxygen evolution kinetics. Herein, the polyaniline (PANI) and cobalt coordinated-phthalocyanines (CoTcPc) were introduced onto the BiVO 4 semiconductor substrate, constructing the integrated CoTcPc/nPANI/BiVO 4 (n = 30, 60 and 90, n represents the deposition time for PANI with the unit of s) composite photoanodes. It is demonstrated that the PEC water oxidation activity of BiVO 4 is significantly boosted by the incorporation of PANI and CoTcPc, stemming from the improved electron/hole transfer, enhanced charge separation efficiency, and accelerated carrier mobility and water oxidation kinetics. CoTcPc/60PANI/BiVO 4 composite photoanode with the optimized compositions exhibits an enhanced photocurrent density of 4.03 mA/cm2 at 1.23 V vs. RHE under illumination, ranking among the best records reported recently. Furthermore, the roles of electrodeposition time to generate PANI are also distinguished through experimental studies. These results reveal the crucial role of engineering the hole transfer layer to optimize the semiconductor photoanodes toward efficient PEC water oxidation. • The water oxidation activity of BiVO 4 is significantly improved. • The synergistic effect significantly contribute to PEC water oxidation activity. • An obviously improved Faradaic efficiency for water oxidation was also achieved. • Engineering the hole transfer layer is an effective method to optimize OER process. [ABSTRACT FROM AUTHOR]

Integration of metalloporphyrin moieties into the porous organic polymer (POP) framework via conjugated linkages can contribute to the hydrogen evolution reaction (HER) performance, due to the interpenetrated macrocyclic hollow channels, and the well-defined catalytic sites. Herein, a porous cobalt porphyrinic network (CoTPP-POP) with benzene linkages was designed and prepared for water reduction. CoTPP-POP exhibits the excellent HER performance with a low overpotential (150 mV at 10 mA cm−2), good long-term durability and remarkable Faradaic efficiency in acidic medium. The HER performance of CoTPP-POP is comparable to many previously reported non-noble electrocatalysts. This contribution demonstrates a facile approach to design other advanced systems for energy-related electrocatalysis. • A porous cobalt porphyrinic network (CoTPP-POP) with benzene linkages was designed. • CoTPP-POP exhibits relative low overpotential of 150 mV to reach 10 mA cm−2. • The effective HER activity is ascribed to a combination of mechanisms. [ABSTRACT FROM AUTHOR]

An organic-inorganic nanohybrid material (TPPOH-GO) is produced by linking monohydroxyporphyrin (TPPOH) and graphene oxide (GO) together via the ester bond, and the formation of this nanohybrid has been affirmed by various spectroscopy techniques. Nonlinear optical (NLO) and optical limiting (OL) performances were studied by the Z-scan technique. Because of the efficient electric charge transfer efficiency between TPPOH and GO, the as-prepared TPPOH-GO nanohybrid exhibits superior NLO and OL performances compared to those of TPPOH and GO. The photophysical, NLO and OL performances of hydrothermally reduced materials (TPPOH-RGO 1, TPPOH-RGO 2, TPPOH-RGO 3) are tuned by controlling the hydrothermal temperatures, implying the scope of using them as optical limiters. • The hybrid material that the porphyrin is covalently linked to GO is reduced for the first time. • Significantly enhanced optical nonlinearity was observed for the material being reduced. • The enhanced performance is ascribed to efficient charge transfer. [ABSTRACT FROM AUTHOR]

Abstract To improve the dispersibility of single walled carbon nanotube (SWCNT) in common organic solvents and adjust its photoelectronic performance, two methacrylate-co-porphyrins covalently functionalized SWCNT nanohybrids (SWCNT-TPP 1 and SWCNT-TPP 2) were prepared by radical polymerization. This attachment of porphyrins onto the surface of SWCNT significantly improves their solubility and dispersion stability of the SWCNT-based materials in organic solvents. The electronic interactions between porphyrins and SWCNT were investigated by the UV–vis, fluorescence and Raman spectroscopic methods. Z-scan measurements suggested that both nanohybrids exhibited increased nonlinear absorption and optical limiting performances compared to the separate SWCNT and porphyrins, which can be ascribed to the synergetic effects originating from the charge transfer effect between the two counterparts. The best optical limiting performance is observed for SWCNT-TPP 1 due to more effective charge transfer effect in comparison with those of other samples. These results suggest that the radical polymerization is a useful approach towards the rational design of solution-processible yet stable optical limiting materials, and this concept may be readily extended to other directional optoelectronic properties. Highlights • Two methacrylate-co-porphyrins covalently functionalized SWCNT were prepared. • The solubility and dispersion stability of the SWCNT were improved. • The enhanced optical limiting was observed due to the efficient charge transfer. [ABSTRACT FROM AUTHOR]

Abstract The polyaniline (PANI) covalently grafted reduced graphene oxide (RGO) nanohybrids (RGO-PANI 1, RGO-PANI 2 and RGO-PANI 3) were fabricated by the in situ synthesis of PANI on the surface of p -phenylenediamine (PPD) functionalized graphene oxide (GO). The formation of RGO-PANI nanohybrids was confirmed by various spectroscopic techniques. The nonlinear optical performances of the as-prepared samples were investigated by the Z-scan measurements at 532 and 1064 nm with 4 ns laser pulses, the results displaying that the chemical nanohybrids (RGO-PANI 1, RGO-PANI 2 and RGO-PANI 3) exhibited enhanced optical nonlinearities compared to those of the benchmark material C 60 , and the constituent RGO and PANI, due to the synergistic effects stemming from charge transfer between the two components. The role of charge transfer in the optical nonlinearity was clarified with the help of photocurrent and electrochemical impedance spectroscopies. By controlling the concentration of original reactants in the precursor, the PANI content in RGO-PANI nanohybrids can be precisely adjusted so that the optical nonlinearity can be tuned. Graphical abstract Due to the efficient charge transfer effect, significant improvement in optical nonlinearities is achieved by covalent grafting of polyaniline onto the surface of reduced graphene oxide. Image 1 Highlights • Three reduced graphene oxide-polyaniline nanohybrids were prepared. • The nanohybrids exhibit efficient optical nonlinearities. • The optical nonlinearity can be tuned by adjusting the original reactant content. • The improved nonlinearity is ascribed to the efficient charge transfer effect. [ABSTRACT FROM AUTHOR]

A facile route to assemble pyridine anchored methine-bridged polypyrrole to metal-porphyrins through axial bonding has been demonstrated, and the as-prepared nanocomposites exhibit very distinctive broadband nonlinear optical performances compared to their precursors at both 532 and 1064 nm, due to an accumulation effect. [ABSTRACT FROM AUTHOR]

A series of novel metal-porphyrins (MTPPs, M(II) = Co, Ni, Cu) hybridized graphite-like carbon nitride (g-C 3 N 4 ) has been successfully synthesized by a facile solvothermal method. The microstructure and chemical structure of the MTPP/g-C 3 N 4 nanocomposites were characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy. The MTPP/g-C 3 N 4 nanocomposites exhibited enhanced photocatalytic performances for the photodegradation of rhodamine B in comparision with those of g-C 3 N 4 and the MTPPs precursors. The excellent photocatalytic performance was observed for CoTPP/g-C 3 N 4 compared to those of g-C 3 N 4 , NiTPP/g-C 3 N 4 and CuTPP/g-C 3 N 4 . The rational mechanisms responsible for deteriorating pollutants were proposed, which could be mainly ascribed to the more effective interfacial charge transfer and the interfacial electronic interactions between CoTPP and g-C 3 N 4 . The UV-visible diffused reflectance spectroscopy, photoluminescence, photocurrent spectroscopy and electrochemical impedance spectroscopy studies confirmed that the charge separation efficiency was greatly improved by coupling g-C 3 N 4 with MTPPs. [ABSTRACT FROM AUTHOR]

The electrochemical water splitting in strongly acidic medium with noble-metal-free electrocatalysts remains a desirable yet technological challenge. Herein, we developed a series of porphyrin coordination polymer supported transition-metal sulfides as bifunctional electrocatalysts (Co 3 S 4 @MoS 2 @nTiPCP, n = 10, 20 or 30) that performs well in acidic media. The optimal Co 3 S 4 @MoS 2 @20TiPCP achieves current densities of 10 mA cm−2 at overpotentials of 247 and 110 mV for acidic OER and HER, respectively. Particularly, an electrolyzer with better long-term stability using Co 3 S 4 @MoS 2 @20TiPCP as both cathode and anode exhibits a low cell voltage of 1.41 V at 10 mA cm−2 in acid, outperforming most other reported electrocatalysts elsewhere. The efficient electrochemical water splitting is ascribed to the synergetic effect and the unique structure characteristics. DFT calculations demonstrate that the Co atoms in Co 3 S 4 @MoS 2 @20TiPCP are the major active sites for electrochemical water splitting thanks to regulated electronic structures and reduced reaction energy barrier. Porphyrin coordination polymer supported transition-metal sulfides exhibit effective overall water splitting in acidic media, due to the synergetic effect between each component and the unique structure characteristics. [Display omitted] • Porphyrin coordination polymer supported metal sulfides as were prepared. • The samples show efficient acidic water electrooxidation. • The efficient acidic electrochemical water splitting is also observed. [ABSTRACT FROM AUTHOR]

Three novel semiconductor composite photoanodes (BiVO 4 /GO/CoTPP(OH) n , n = 1, 4 and 8) are designed and prepared by decorating BiVO 4 with graphene oxide (GO) and cobalt porphyrins bearing different number of hydroxyl groups. The introduction of GO and CoTPP(OH) n onto the BiVO 4 surface has been confirmed by transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, Fourier transform infrared and Raman spectroscopic techniques, endowing BiVO 4 with improved charge transfer and broadened light absorption ability. Their viability as photoelectrochemical system is investigated under AM 1.5 G light irradiation, the photoelectrochemical water splitting performance being found to be dependent on the type of cobalt porphyrins. The BiVO 4 /GO/CoTPP(OH) 4 is found to exhibit the largest photocurrent density of 5.27 mA/cm−2 at 1.23 V vs. RHE due to a combination of mechanisms. • Porphyrin and GO decorated BiVO4 photoanodes have been successfully developed. • The introduction of porphyrin and GO can improve the charge transfer efficiency. • The type of porphyrins has a significant influence on the PEC water splitting. • The obtained photoanodes exhibit efficient performance in PEC water splitting. [ABSTRACT FROM AUTHOR]

In this contribution, we disclose that reaction of the tetrakis(4-aminophenyl)porphyrin (TPP) and tetraaminophthalocyanine (ZnPc) with GO gives a donor-acceptor type hybrid material (TPP-GO-ZnPc). An analysis of the structure-property relationships in redox and optoelectronic performances has been performed by comparing their photophysical spectroscopy and electrochemistry. The results reveal that the resultant TPP-GO-ZnPc ternary nanohybrid exhibits enhanced optical limiting and HER response in comparison with those of TPP-functionalized GO (TPP-GO), ZnPc-functionalized GO (ZnPc-GO) and their constituents, stemming from a combination of mechanisms and more effective charge transfer effect. The strong electronic interactions and charge transfer effect within TPP-GO-ZnPc has been investigated by the UV–Vis absorption, photocurrent response, fluorescence and electrochemical impedance spectrum. • TPP-GO-ZnPc ternary nanohybrid was prepared. • The ternary nanohybrid exhibits enhanced optical limiting and HER. • The improved performance is assigned to a combination of mechanisms. [ABSTRACT FROM AUTHOR]

Herein, a novel porous titanium coordination polymer (TiCP-PCP) with push-pull motif is prepared through the transesterification reaction of catechol porphyrin with titanium tetraisopropoxide. TiCP-PCP demonstrates efficient electrocatalytic activity toward HER/OER with prominent electrochemical durability in acid/basic medium. Surprisingly, TiCP-PCP requires relatively low overpotentials of 339 and 310 mV to reach a catalytic current density of 10 mA cm−2 for HER and OER, respectively. Based on experimental and theoretical results, the improved electrocatalytic performances for TiCP-PCP in comparison with those of TPP and TiO 2 are ascribed to efficient charge transfer and positive synergistic effect, stemming from the interactions between porphyrin units and Ti entities. This work can be readily extended to a wide range of porous coordination polymer-based electrochemical devices and catalysts design. A novel porous titanium coordination polymer with push-pull motif was designed and prepared through the transterification reaction of catechol porphyrin with titanium tetraisopropoxide. TiCP-PCP demonstrated efficient electrocatalytic activity toward HER/OER with prominent electrochemical durability in acid/basic medium. Image 1 • A novel porous titanium coordination polymer with push-pull motif was designed. • This polymer can provide abundant active sites for hydrogen and oxygen evolution. • The prepared polymer exhibited excellent electrocatalysis. • The improved electrocatalysis was assigned to a combination of mechanisms. [ABSTRACT FROM AUTHOR]

Rational design of efficient hydrogen evolution reaction (HER) electrocatalysts, constructed with earth-abundant elements, is critical for developing sustainable alternative energy sources. Herein, two phosphonitrilic-bridged metal porphyrin porous covalent organic polymers (COPs) were developed for HER. Compared to CoTPP-PCTCOP, NiTPP-PCTCOP exhibits relative low overpotentials of 140 to reach 10 mA cm−2 for HER in alkaline medium, which is comparable to many previously reported state-of-the-art electrocatalysts. The enhanced HER activity of NiTPP-PCTCOP is associated with its chemical composition and special push-pull structure. Long-term stability analysis of NiTPP-PCTCOP shows that the current density exhibits no obvious deactivation over a long time test. This work demonstrates an effective technique to develop promising HER electrocatalysts, highlighting its advantages by combing phosphonitrilic chloride trimer with metal porphyrins. [Display omitted] • Two phosphonitrilic-bridged metal porphyrin COPs were developed for HER. • NiTPP-PCTCOP exhibits relative low overpotentials of 140 to reach 10 mA cm−2. • The effective HER activity is associated with its special push-pull structure. [ABSTRACT FROM AUTHOR]

Abstract In this work, a series of pyrimidine/g-C 3 N 4 photocatalysts has been synthesized via a facile solvothermal method for the first time. The structure, elemental composition and morphology of the photocatalysts were characterized by FT-IR, SEM, XPS, N 2 adsorption-desorption isotherms and BET characterization methods. The photocatalytic activity of the pyrimidine/g-C 3 N 4 materials was investigated by the degradation of rhodamine solution under visible-light illumination. The pyrimidine/g-C 3 N 4 photocatalyst with 1 wt% of pyrimidine shows the highest photocatalytic activity for the degradation of RhB, which can be mainly ascribed to the effective interfacial charge transfer within the pyrimidine/g-C 3 N 4 photocatalyst and the cooperation effect of the excellent contact interface between g-C 3 N 4 and pyrimidine. The main active species during the photodegradation process are determined by the radical trapping experiments, proving that the superoxide radical (•O 2 −) and the hydroxyl radical (•OH) play the main role in the photocatalytic reactions. Highlights • A series of pyrimidine/g-C 3 N 4 photocatalysts has been synthesized. • The content of pyrimidine has a significant effect on the photocatalysis. • The enhanced photocatalysis is ascribed to the efficient charge transfer. [ABSTRACT FROM AUTHOR]

The combination of graphene oxide and different porphyrins is attracted much attention as optical limiting systems. In this article, three novel porphyrins covalently functionalized GO nanohybrids (TPP-GO, TTP-GO and TPP-GO-TTP) have been designed and synthesized by covalent functionalization approach. The formation of these nanohybrids has been confirmed by various spectroscopic techniques including Fourier transform infrared spectroscopy, Raman, scanning electron microscope images, X-ray photoelectron spectroscopy and thermogravimetric analysis. Raman spectra and photophysical studies demonstrated effective charge transfer effect from the porphyrins to the GO. The as-prepared nanohybrids exhibited superior nonlinear absorption and optical limiting performances exciting by the 4 ns laser pulses, significantly better than their components due to more effective charge transfer effect. Particularly, the TPP-GO-TTP ternary nanohybrid showed the best nonlinear optical and optical limiting properties in comparison with those of other both binary nanohybrids, highlighting the influence of the introduction of different porphyrins on the photophysical and optical limiting performances of the as-prepared nanohybrids. • One graphene oxide ternary nanohybrid was prepared. • Enhanced optical limiting was observed for the nanohybrid. • The efficient charge transfer responsibles for improved optical nonlinearity. [ABSTRACT FROM AUTHOR]