The catalytic activity of metal phthalocyanine (MPc) heterogeneous catalyst is determined by both the microstructure of the support and the electron transfer efficiency of MPc during the reaction process. Inspired by this, we developed a novel, highly-efficient heterogeneous MPc catalyst based on the construction of a “reaction-involved” support. Graphene incorporated bacterial cellulose (G/BC) nanohybrid was conveniently prepared by an in situ biosynthetic method for the subsequent immobilization of tetraamino cobalt(II) phthalocyanine (CoPc) catalyst. The resulting graphene incorporated, CoPc decorated bacterial cellulose nanocomposite (CoPc@G/BC) was applied for decoloration of dye solutions, the G/BC support was deeply involved in the reaction process. The unique three-dimensional web-like framework structure of G/BC and the high affinity of graphene markedly promote the accessibility of reactants to the active sites of CoPc@G/BC, and the equilibrium adsorption data were best fitted by Freundlich model. With H 2 O 2 as an oxidant, dye molecules were catalytically oxidized by CoPc@G/BC, a ca. 70% enhancement of decoloration capacity was achieved with the incorporation of graphene. The catalytic oxidation was analyzed by electron paramagnetic resonance, highly reactive hydroxyl radical (·OH) was identified during the reaction, and the incorporated graphene can obviously promote the formation of ·OH. A potential mechanism of enhancement of catalytic activity of CoPc with G/BC support was originally proposed.
Ding Jie,Wei Zhiming,Li Fuhua,Zhang Jincheng,Zhang Qiao,Zhou Jing,Wang Weijue,Liu Yuhang,Zhang Zhen,Su Xiaozhi,Yang Runze,Liu Wei,Su Chenliang,Yang Hong Bin,Huang Yanqiang,Zhai Yueming,Liu Bin
In this work, via engineering the conformation of cobalt active center in cobalt phthalocyanine molecular catalyst, the catalytic efficiency of electrochemical carbon monoxide reduction to methanol can be dramatically tuned. Based on a collection of experimental investigations and density functional theory calculations, it reveals that the electron rearrangement of the Co 3d orbitals of cobalt phthalocyanine from the low-spin state (S = 1/2) to the high-spin state (S = 3/2), induced by molecular conformation change, is responsible for the greatly enhanced CO reduction reaction performance. Operando attenuated total reflectance surface-enhanced infrared absorption spectroscopy measurements disclose accelerated hydrogenation of CORR intermediates, and kinetic isotope effect validates expedited proton-feeding rate over cobalt phthalocyanine with high-spin state. Further natural population analysis and density functional theory calculations demonstrate that the high spin Co 2+ can enhance the electron backdonation via the d xz / d yz −2π* bond and weaken the C-O bonding in *CO, promoting hydrogenation of CORR intermediates.
Manipulating the morphology and protonic acid doping of polyaniline (PANI) is significant for optimizing its NH3-sensing. Herein, tetra-β-carboxyphthalocyanine cobalt(II) (TcPcCo) acted as the dopant and structure-directing agent simultaneously to fabricate the uniform fibrous network-like PANI (PANI-TcPcCo hybrids) by a one-step polymerization at low temperature. During the reaction process, the protonic acid groups in TcPcCo not only induced the aniline monomers polymerizing into one-dimensional nanofibers (consist of both solid and hollow cylinders) with abundant tiny protuberances on the surface but also successfully doped into PANI. The resulting PANI-TcPcCo hybrids displayed the enhancement in terms of the good conductivity, the large gas adsorption capacity, and the unobstructed channels for the electron and gas transport. The central metal atoms of TcPcCo present the strong and selective affinity to NH3. Meanwhile, the deep-seated conversion of PANI’s molecular structure after exposure in NH3 could occur due to the presence of TcPcCo. Thus, the PANI-2.5TcPcCo sensor showed the excellent NH3-sensing performance at room temperature, including an ultrahigh and fast response (802.7% and ∼17.0 s for 100 ppm of NH3), a very low detection limit of 10 ppb (about 5000 parts of human olfaction limit of detection, 55 ppm), and superior NH3-sensing stability and selectivity. The strategy developed here provides a reliable and valid way to synthesize functional PANI-based hybrids with unique morphology and appropriate doping, which are able to be extended to other areas.
危险品化学品经营许可证（带存储）