Effects of BET Surface Area and Silica Hydrophobicity on Natural Rubber Latex Foam Using the Dunlop Process.

To reinforce natural rubber latex foam, fumed silica and precipitated silica are introduced into latex foam prepared using the Dunlop process as fillers. Four types of silica, including Aerosil 200 (hydrophilic fumed silica), Reolosil DM30, Aerosil R972 (hydrophobic fumed silica), and Sipernat 22S (precipitated silica), are investigated. The latex foam with added silica presents better mechanical and physical properties compared with the non-silica foam.

Electrocatalytic Nitrate and Nitrite Reduction toward Ammonia Using CuO Nanocubes: Active Species and Reaction Mechanisms.

The electrochemical reduction of nitrate (NO) and nitrite (NO) enables sustainable, carbon-neutral, and decentralized routes to produce ammonia (NH). Copper-based materials are promising electrocatalysts for NO conversion to NH. However, the underlying reaction mechanisms and the role of different Cu species during the catalytic process are still poorly understood.

Enhancing Devulcanizing Degree and Efficiency of Reclaimed Rubber by Using Alcoholic Amines as the Devulcanizing Agent in Low-Temperature Mechano-Chemical Process.

Low-temperature mechanical chemical devulcanization is a process that can produce reclaimed rubber with exceptional mechanical properties. However, the inadequacy and low efficiency of the devulcanization have significantly restricted its application. To address the issues, alcoholic amines, including hydroxyethyl ethylenediamine (AEEA), ethanolamine (ETA), and diethanol amine (DEA), are utilized as devulcanizing agents to promote the devulcanization process.

Improving Dispersion of Carbon Nanotubes in Natural Rubber by Using Waterjet-Produced Rubber Powder as a Carrier.

Carbon nanotube (CNT), as reinforcing agents in natural rubber (NR), has gained a large amount of consideration due to their excellent properties. Uniform dispersion of CNT is the key to obtaining high-performance NR nanocomposites. In this contribution, a novel ultrasonic grinding dispersion method of CNT with waterjet-produced rubber powder (WPRP) as a carrier is proposed.

Modulating the Site Density of Mo Single Atoms to Catch Adventitious O Atoms for Efficient H O Oxidation with Light.

Coordination environment and site density have great impacts on the catalytic performance for single atoms (SAs). Herein, the site density of Mo-SAs on red polymeric carbon nitrides (RPCN) is modulated via a local carbonization strategy to controllably catch adventitious O atoms from open environment. The addition of melamine derivants with hydrocarbyl chains induces local carbonization during RPCN pyrolysis.

Recycling of Flexible Polyurethane Foams by Regrinding Scraps into Powder to Replace Polyol for Re-Foaming.

In the context of protecting the ecological environment and carbon neutrality, high-value recycling of flexible polyurethane foam (F-PUF) scraps, generated in the production process, is of great significance to save petroleum raw materials and reduce energy consumption. In the present study, F-PUF scraps were ground into powder by strong shear regrinding using two-roll mill and then reused as a partial replacement of polyol for re-foaming. A series of characterizations were employed to investigate the effect of milling cycles, roller temperatures, and content of the powder on the properties of the powder and F-PUF containing powder.

Efficient Electrochemical Nitrate Reduction to Ammonia with Copper-Supported Rhodium Cluster and Single-Atom Catalysts.

The electrochemical nitrate reduction reaction (NITRR) provides a promising solution for restoring the imbalance in the global nitrogen cycle while enabling a sustainable and decentralized route to source ammonia. Here, we demonstrate a novel electrocatalyst for NITRR consisting of Rh clusters and single-atoms dispersed onto Cu nanowires (NWs), which delivers a partial current density of 162 mA cm for NH production and a Faradaic efficiency (FE) of 93 % at -0.2 V vs.

Spectroscopic and Electrokinetic Evidence for a Bifunctional Mechanism of the Oxygen Evolution Reaction*.

A bifunctional oxygen evolution reaction (OER) mechanism, in which the energetically demanding step of the attack of hydroxide on a metal oxo unit is facilitated by a hydrogen atom transfer to a second site, has the potential to circumvent the scaling relationship. However, the bifunctional mechanism has hitherto only been supported by theoretical computations. Here we describe an operando Raman spectroscopic and electrokinetic study of two highly active OER catalysts, FeOOH-NiOOH and NiFe layered double hydroxide (LDH).

Strategies for Semiconductor/Electrocatalyst Coupling toward Solar-Driven Water Splitting.

Hydrogen (H) has a significant potential to enable the global energy transition from the current fossil-dominant system to a clean, sustainable, and low-carbon energy system. While presently global H production is predominated by fossil-fuel feedstocks, for future widespread utilization it is of paramount importance to produce H in a decarbonized manner. To this end, photoelectrochemical (PEC) water splitting has been proposed to be a highly desirable approach with minimal negative impact on the environment.

Deciphering Iron-Dependent Activity in Oxygen Evolution Catalyzed by Nickel-Iron Layered Double Hydroxide.

Nickel iron oxyhydroxide is the benchmark catalyst for the oxygen evolution reaction (OER) in alkaline medium. Whereas the presence of Fe ions is essential to the high activity, the functions of Fe are currently under debate. Using oxygen isotope labeling and operando Raman spectroscopic experiments, we obtain turnover frequencies (TOFs) of both Ni and Fe sites for a series of Ni and NiFe layered double hydroxides (LDHs), which are structurally defined samples of the corresponding oxyhydroxides.

A Cobalt-Iron Double-Atom Catalyst for the Oxygen Evolution Reaction.

Single-atom catalysts exhibit well-defined active sites and potentially maximum atomic efficiency. However, they are unsuitable for reactions that benefit from bimetallic promotion such as the oxygen evolution reaction (OER) in an alkaline medium. Here we show that a single-atom Co precatalyst can be in situ transformed into a Co-Fe double-atom catalyst for the OER.

Atomically dispersed Fe sites catalyze efficient CO electroreduction to CO.

Currently, the most active electrocatalysts for the conversion of CO to CO are gold-based nanomaterials, whereas non-precious metal catalysts have shown low to modest activity. Here, we report a catalyst of dispersed single-atom iron sites that produces CO at an overpotential as low as 80 millivolts. Partial current density reaches 94 milliamperes per square centimeter at an overpotential of 340 millivolts.

Metal-Sulfide Catalysts Derived from Lignosulfonate and their Efficient Use in Hydrogenolysis.

Catalytic lignosulfonate valorization is hampered by the in situ liberation of sulfur that ultimately poisons the catalyst. To overcome this limitation, metal sulfide catalysts were developed that are able to cleave the C-O bonds of lignosulfonate and are resistant to sulfur poisoning. The catalysts were prepared by using the lignosulfonate substrate as a precursor to form well-dispersed carbon-supported metal (Co, Ni, Mo, CoMo, NiMo) sulfide catalysts.

Alkene hydrosilylation catalyzed by easily assembled Ni(ii)-carboxylate MOFs.

We report the first Ni MOF catalysts for anti-Markovnikov hydrosilylation of alkenes. These catalysts are bench-stable and easily-assembled from simple Ni salts and carboxylic acids. The best catalyst gives turnover numbers up to 9500 and is robust even after 10 recycling runs.

Transition Metal Oxides as Electrocatalysts for the Oxygen Evolution Reaction in Alkaline Solutions: An Application-Inspired Renaissance.

Water splitting is the essential chemical reaction to enable the storage of intermittent energies such as solar and wind in the form of hydrogen fuel. The oxygen evolution reaction (OER) is often considered as the bottleneck in water splitting. Though metal oxides had been reported as OER electrocatalysts more than half a century ago, the recent interest in renewable energy storage has spurred a renaissance of the studies of transition metal oxides as Earth-abundant and nonprecious OER catalysts.

Highly Efficient Photoelectrochemical Water Splitting with an Immobilized Molecular Co O Cubane Catalyst.

Molecular Co O cubane water oxidation catalysts were combined with BiVO electrodes for photoelectrochemical (PEC) water splitting. The results show that tuning the substituent groups on cobalt cubane allows the PEC properties of the final molecular catalyst/BiVO hybrid photoanodes to be tailored. Upon loading a new cubane complex featuring alkoxy carboxylato bridging ligands (1 h) on BiVO , an AM 1.

Visible-Light-Driven Water Oxidation on a Photoanode by Supramolecular Assembly of Photosensitizer and Catalyst.

A ruthenium water oxidation catalyst (WOC) bearing hydrophobic ligands was incorporated on the surface of a dye-sensitized nanostructured TiO film by formation of a host-guest adduct with the dye. This provides a new strategy for constructing photocatalytically active electrodes for water oxidation. The resultant photoanode exhibits a photocurrent of 800 μA cm under visible-light illumination (λ>400 nm, 300 mW cm ) and 240 μA cm under simulated sunlight illumination (AM 1.

Electrocatalytic water oxidation by a macrocyclic Cu(ii) complex in neutral phosphate buffer.

A single-site copper complex, [Cu(TMC)(H2O)](NO3)2 (1, TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane), was found to be the most active copper-based catalyst towards electrocatalytic water oxidation in neutral aqueous solution. Complex 1 leads to a cathodic shift of approximately 200 mV in potential to reach a current density of 1 mA cm(-2) in comparison with that of the previously reported dinuclear copper complex under the same conditions. Upon immobilization of complex 1 on carbon cloth, it shows greatly improved activity than other copper-based WOCs including CuOx and Cu(2+).

Visible-light-driven selective oxidation of benzyl alcohol and thioanisole by molecular ruthenium catalyst modified hematite.

Molecular ruthenium catalysts were found to selectively catalyze the oxidation of thioanisole to sulfoxide with a yield up to 100% in the presence of visible light and sacrificial reagents when they were anchored onto hematite powder. The composite photocatalysts also showed about 5 times higher efficiencies in benzyl alcohol oxidation than the system composed of dispersed molecular catalysts and hematite particles in aqueous solution. A photoelectrochemical cell based on a molecular catalyst modified hematite photoanode was further fabricated, which exhibited high activity towards the oxidation of organic substrates.

An iron-based thin film as a highly efficient catalyst for electrochemical water oxidation in a carbonate electrolyte.

A highly active iron-based water-oxidation catalyst was electrodeposited from a CO2 saturated bicarbonate solution containing Fe(2+). This catalyst (Fe-Ci) produces a current density of 10 mA cm(-2) at an overpotential of 560 mV and the activity remains constant over 18 h in the environmentally benign HCO3(-)/CO3(2-) buffer (pH 9.75).

Photocatalytic water oxidation via combination of BiVO4-RGO and molecular cobalt catalysts.

A BiVO4-reduced graphene oxide (RGO) composite in conjugation with the cubic molecular complex Co4O4(O2CMe)4(py)4 (py = pyridine) has been found to be highly efficient towards visible light-driven water oxidation. A 4-fold enhancement in the average oxygen evolution rate and 100% yield based on the consumption of the sacrificial electron acceptor were obtained upon the addition of molecular cocatalysts to BiVO4-RGO in pure water.