Fabrication of highly dispersed platinum-deposited porous g-C_3N_4 by a simple in situ photoreduction strategy and their excellent visible light photocatalytic activity toward aqueous 4-fluorophenol degradation

A series of highly dispersed platinum‐deposited porous g‐C3N4 (Pt/pg‐C3N4) were successfully fabricated by a simple in situ photoreduction strategy using chloroplatinic acid and porous g‐C3N4 as precursors. Porous g‐C3N4 was fabricated by a pretreatment strategy using melamine as a raw material.The morphology, porosity, phase, chemical structure, and optical and electronic properties ofas‐prepared Pt/pg‐C3N4 were characterized. The photocatalytic activity of as‐prepared Pt/pg‐C3N4was preliminarily evaluated by the degradation of aqueous azo dyes methyl orange under visible light irradiation. The as‐prepared Pt/pg‐C3N4 were further applied to the degradation and mineralization of aqueous 4‐fluorophenol. The recyclability of Pt/pg‐C3N4 was evaluated under four consecutive photocatalytic runs.

Iron-incorporated nitrogen-doped carbon materials as oxygen reduction electrocatalysts for zinc-air batteries

The application of electrocatalysts for the oxygen reduction reaction(ORR) is vital in a variety of energy conversion technologies. Exploring low-cost ORR catalysts with high activity and long-term stability is highly desirable, although it still remains challenging. Herein, we report a facile and reliable route to convert ZIF-8 modified by Fe-phenanthroline into Fe-incorporated and N-doped carbon dodecahedron nanoarchitecture(Fe-NCDNA), in which carbon nanosheets are formed in situ as the building blocks with uniform Fe-N-C species decoration. Systematic electrochemical studies demonstrate that the as-synthesized Fe-NCDNA electrocatalyst possesses highly attractive catalytic features toward the ORR in terms of activity and durability in both alkaline and neutral media. The Zn-air battery with the optimal Fe-NCDNA catalyst as the cathode performs impressively, delivering a power density of 184 m W cm^–2 and a specific capacity of 801 m Ah g^–1;thus, it exhibits great competitive advantages over those of the Zn-air devices employing a Pt-based cathode electrocatalyst.

Synergistic photocatalytic effect of porous g-C_3N_4 in a Cr(Ⅵ)/4-chlorophenol composite pollution system

The photocatalytic reduction of aqueous Cr(VI)to Cr(III)was preliminarily studied using porousg‐C3N4as a photocatalyst under acidic conditions.The observed synergistic photocatalytic effect ofporous g‐C3N4on a Cr(VI)/4‐chlorophenol(4‐CP)composite pollution system was further studiedunder different pH conditions.Compared with single‐component photocatalytic systems for Cr(VI)reduction or4‐CP degradation,the Cr(VI)reduction efficiency and4‐CP degradation efficiency weresimultaneously improved in the Cr(VI)/4‐CP composite pollution system.The synergistic photocatalyticeffect in the Cr(VI)/4‐CP composite pollution system can be attributed to the acceleratedredox reaction between dichromate and4‐CP by electron transfer with porous g‐C3N4.

基于硅烷化启动的环化反应研究进展

有机硅化合物是许多材料的重要基元和有用的有机分子,是化学合成中用途广泛的合成中间体.因此,化学家们一直致力于开发构建含硅化学键的新方法,特别是C—Si键.自从Sakurai和Imai在1975年报道了第一个钯催化的硅环丁烷与炔的环加成反应以来,过渡金属催化硅基环化反应得到了迅速的发展.随着自由基反应的迅猛发展,研究者将其拓展到有机硅分子间环化反应,硅的环化反应迎来了新的发展.主要从过渡金属催化的硅环化反应、自由基引发的硅环化反应、C^(+)离子引发的硅环化反应展开讨论,最后对当前的研究进展进行了总结.