Progress toward Polymerization Reaction Monitoring with Different Dienes: How Small Amounts of Dienes Affect -Zirconocenes/Borate/Triisobutylaluminium Catalyst Systems.

The objectives of this work were to address the fundamental characteristics of ansa-zirconocene catalyzed E/diene copolymerization and E/diene/1-hexene and E/diene/propylene terpolymerizations, and the quantitative relationship between diene structure and polymer chain propagation rate constant in term of quantifiable catalytic active sites. One of the most important but unknown factors in olefins ansa-zirconocene complexes is the distribution of the catalyst between sites actively participating in polymer chain formation and dormant sites. A set of ethylene/dienes copolymerizations, and ethylene/dienes/1-hexene and ethylene/dienes/1-hexene terpolymerizations catalyzed with -zirconocenes/borate/triisobutylaluminium (-Et(Ind)ZrCl/[PhC][B(CF)]/triisobutylaluminium (TIBA) were performed in toluene at 50 °C To determine the active center [C*]/[Zr] ratio variation in the copolymerization of E with different dienes and their terpolymerization with 1-hexene and propylene, each polymer propagation chain ends were quenched with 2-thiophenecarbonyl, which selectively quenches the metal-polymer bonds through acyl chloride.

Sulfur doped FeNC catalysts derived from Dual-Ligand zeolitic imidazolate framework for the oxygen reduction reaction.

Iron-nitrogen-carbon (FeNC) catalysts derived from zeolitic-imidazolate frameworks (ZIFs) are worldwide accepted to be the most promising candidates for the oxygen reduction reaction (ORR), but the insufficient stability, the low FeN exposure and poor density restrict their ORR activity. Here, we demonstrate a strategy to synthesize FeN sites embedded in a micro/mesoporous N, S co-doped graphitic carbon (FeNC/MUS) by tuning the ligand linkers via the addition of 2-undecylimidazole as a co-ligand in ZIF precursors, and optimizing the electronic structure of Fe center by an in-situ addition of thiourea molecules as sulfur (S) source. 2-undecylimidazole offered an open porous structure to incorporate more FeN, while the S-doping increased the density of FeN.

Correction: Rapid kinetic evaluation of homogeneous single-site metallocene catalysts and cyclic diene: how do the catalytic activity, molecular weight, and diene incorporation rate of olefins affect each other?

[This corrects the article DOI: 10.1039/D1RA06243C.].

Rapid kinetic evaluation of homogeneous single-site metallocene catalysts and cyclic diene: how do the catalytic activity, molecular weight, and diene incorporation rate of olefins affect each other?

The kinetics and mechanism of ethylene and cyclic diene 5-ethylidene-2-norbornene (ENB) copolymerization catalyzed by -Et(Ind)ZrCl/[PhC][B(CF)]/triisobutylaluminium (TIBA) were investigated using a quench-labeling procedure using 2-thiophenecarbonyl chloride (TPCC). The E/ENB copolymers were characterized by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and H nuclear magnetic resonance (NMR) spectroscopy and sulfur analysis. To reduce the errors of the ethylene-diene copolymerization for the kinetics study, we selected E/ENB with steric and electronic features that permit us to elucidate the metallocene catalyst behavior against dienes.

Dual plasmonic Au and TiN cocatalysts to boost photocatalytic hydrogen evolution.

Employing a suitable cocatalyst is very important to improve photocatalytic H evolution activity. Herein, two plasmonic cocatalysts, Au nanoparticles and TiN nanoparticles were in-situ coupled over the g-CN nanotube to form a ternary 0D/0D/1D Au/TiN/g-CN composite via a successive thermal polycondensation and chemical reduction method. The g-CN nanotube acted as a support for the growth of Au and TiN nanoparticles, leading to intimate contact between g-CN nanotube with Au nanoparticles and TiN nanoparticles.

A 3D nitrogen-doped graphene aerogel for enhanced visible-light photocatalytic pollutant degradation and hydrogen evolution.

Three-dimensional (3D) graphene-based aerogels have attracted widespread interest as promising photocatalysts for dye degradation and hydrogen production. Herein, we have developed a 3D nitrogen-doped graphene aerogel (3DNG) from graphitic carbon nitride combined with graphene oxide (GO). The nitrogen dopant in the 3D aerogel was achieved a thermal treatment at 1000 °C, and the 3D aerogel catalyst could retain its 3D porous structure after the thermal treatment.

N,S-Atom-coordinated CoS trinary dopants within a porous graphene framework as efficient catalysts for oxygen reduction/evolution reactions.

The intrinsic instability and difficulty in controlling the uniform size distributions of cobalt sulfides greatly restrict their application for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) as a bifunctional electrocatalyst in regenerative fuel cells and rechargeable metal-air batteries. Herein, we synthesize a stable electrocatalyst of N,S-atom-coordinated Co9S8 trinary dopants within a porous graphene framework (Co9S8@NS-3DrGO), in which Co9S8 nanoparticles show uniform sizes and distributions. The stable Co9S8-based composites are fabricated by a facile soft template-assisted strategy, and the attraction of this method is that the intermediate of melamine formaldehyde resin (MFR) plays trifunctional roles, including (i) it acts as the templated bonding material to crosslink GO sheets together, (ii) it facilitates the formation of a core-shell architecture, and (iii) it acts as the N source for doping.