Simultaneous formation of sorbitol and gluconic acid from cellobiose using carbon-supported ruthenium catalysts

A carbon-supported Ru catalyst, Ru/BP2000, is able to simultaneously convert cellobiose into sorbitol and gluconic acid. This reaction occurs as the result of hydrolytic disproportionation in water at 393 K under an Ar atmosphere, without bases or sacrificial reagents. In-situ XANES measurements suggest that the active Ru species involved is composed of partially oxidized Ru metal.

Boosting Fischer-Tropsch Synthesis via Tuning of N Dopants in TiO_(2)@CN-Supported Ru Catalysts

Nitrogen(N)-doped carbon materials as metal catalyst supports have attracted signifi cant attention,but the eff ect of N dopants on catalytic performance remains unclear,especially for complex reaction processes such as Fischer-Tropsch synthesis(FTS).Herein,we engineered ruthenium(Ru)FTS catalysts supported on N-doped carbon overlayers on TiO_(2)nanoparticles.By regulating the carbonization temperatures,we successfully controlled the types and contents of N dopants to identify their impacts on metal-support interactions(MSI).Our fi ndings revealed that N dopants establish a favorable surface environment for electron transfer from the support to the Ru species.Moreover,pyridinic N demonstrates the highest electron-donating ability,followed by pyrrolic N and graphitic N.In addition to realizing excellent catalytic stability,strengthening the interaction between Ru sites and N dopants increases the Ru^(0)/Ru^(δ+)ratios to enlarge the active site numbers and surface electron density of Ru species to enhance the strength of adsorbed CO.Consequently,it improves the catalyst’s overall performance,encompassing intrinsic and apparent activities,as well as its ability for carbon chain growth.Accordingly,the as-synthesized Ru/TiO_(2)@CN-700 catalyst with abundant pyridine N dopants exhibits a superhigh C_(5+)time yield of 219.4 mol CO/(mol Ru·h)and C_(5+)selectivity of 85.5%.

CATALYTIC PERFORMANCE OF MIXED-BIMETALLIC RUTHENIUM CARBONYL CLUSTERDERIVED CATALYSTS IN CO HYDROGENATION

The bimetallic catalysts prepared from SiO_2-supported Ru-Co,Ru- Fe and Ru-Mo carbonyl clusters exhibited high yields and selectivities towards oxygenates such as C_1-C_5 from CO+H_2,in contrast to the catalysts prepared from homometallic and bimetallic Ru,Ru-Ni,Ru-Rh,Ru-Mn,and Ru- Cr carbonyl clusters.The FTIR investigation revealed that the 1584 cm^(-1) species plays an important role in the formation of oxygenates in CO hydrogenation,which is possibly assigned to surface formyl species.

Selective Oxidation of CO in Excess H_2 over Ru/Al_2O_3 Catalysts Modified with Metal Oxide

The Ru/Al2O3 catalysts modified with metal oxide （K20 and La2O3） were prepared v/a incipient wetness impregnation method from RuCl3.nH2O mixed with nitrate loading on Al2O3 support. The activity of catalysts was evaluated under simulative conditions for the preferential oxidation of CO （CO-PROX） from the hydrogen-rich gas streams produced by reforming gas, and the performances of catalysts were investigated by XRD and TPR. The results showed that the activity temperature of the modified catalysts Ru-K20/Al2O3 and Ru-La2O3/Al2O3 were lowered approximately 30℃ compared with pure Ru/Al2O3, and the activity temperature range was widened. The conversion of CO on Ru-K20/Al2O3 and Ru-La2O3/Al2O3 was above 99% at 140-160℃, suitable to remove CO in a hydrogen-rich gas and the selectivity of Ru-La2O3/Al2O3 was higher than that of Ru-K2O/Al2O3in the active temperature range. Slight methanation reaction was detected at 220℃ and above.

Synthesis and Catalytic Activity of a Two-core Ruthenium Carbene Complex: a Unique Catalyst for Ring Closing Metathesis Reaction

The reaction of a ruthenium carbide complex RuCl2（C：）（PCy3）2 with [H（Et2O）x]＋[BF4]- at a molar ratio of 1：2 produced a two-core ruthenium carbene complex, {[RuCl（=CHPCy3）（PCy3）]2（μ-Cl）3}＋·[BF4]-, in the form of a yellow-green crystalline solid in a yield of 94%. This two-core ruthenium complex is a selective catalyst for ring closing metathesis of unsubstituted terminal dienes. More importantly, no isomerized byproduct was observed for N-substrates when the two-core ruthenium complex was used as the catalyst at an elevated temperature（137 °C）, indicating that the complex is a chemo-selective catalyst for ring closing metathesis reactions.

Sustainable Ammonia Synthesis from Nitrogen and Water by One-Step Plasma Catalysis

Sustainable ammonia synthesis at ambient conditions that relies on renewable sources of energy and feedstocks is globally sought to replace the Haber-Bosch process.Here,using nitrogen and water as raw materials,a nonthermal plasma catalysis approach is demonstrated as an effective powerto-chemicals conversion strategy for ammonia production.By sustaining a highly reactive environment,successful plasma-catalytic production of NH_(3) was achieved from the dissociation of N_(2) and H_(2)O under mild conditions.Plasma-induced vibrational excitation is found to decrease the N_(2) and H_(2)O dissociation barriers,with the presence of matched catalysts in the nonthermal plasma discharge reactor contributing significantly to molecular dissociation on the catalyst surface.Density functional theory calculations for the activation energy barrier for the dissociation suggest that ruthenium catalysts supported on magnesium oxide exhibit superior performance over other catalysts in NH_(3) production by lowering the activation energy for the dissociative adsorption of N_(2) down to 1.07 eV.The highest production rate,2.67 mmol gcat.^(-1) h^(-1),was obtained using ruthenium catalyst supported on magnesium oxide.This work highlights the potential of nonthermal plasma catalysis for the activation of renewable sources to serve as a new platform for sustainable ammonia production.

Boosting the Performance Gain of Ru/C for Hydrogen Evolution Reaction Via Surface Engineering

The surface properties of catalysts determine the intrinsic activity and adaptability.Ruthenium is regarded as a potential candidate to substitute platinum for water electrolysis due to the low cost and analogous electronic structures while it suffers from severe dissolution and stability problems.Herein,the modification of Ru/C with atomically dispersed cobalt atoms is achieved via a simple thermal doping method.The newly formed amorphous shell with Ru-Co sites on the Ru/C catalyst improved the hydrogen evolution reaction activity and stability significantly.Impressively,the obtained Co1Ru@Ru/CN_(x)catalyst exhibited an overpotential as low as 30 mV at 10 mA cm^(-2)in an alkaline medium,which is among the best HER catalysts reported so far.The oxygen oxophile Co prevents the fast oxidation and dissolution of Ru species,ensuring outstanding long-term durability up to 70 h.Theoretical calculations reveal that the Ru-Co coordination acts as a more active site for water dissociation than the Ru-Ru.Meanwhile,the"Ru-Co shell/Ru core"structures show high adaptability for the reaction conditions.This simple doping strategy offers prospects for scalable preparation of highly active electrocatalysts.

Catalytic wet air oxidation of phenol over RuO_2/γ-Al_2O_3 catalyst

A kind of CWAO catalyst, RuO_2/γ-Al_2O_3, was prepared by dipping Al_2O_3into the aqueous solution of RuCl_3·3H_2O. XRD, SEM and TEM were used to determine the catalyticstructure. Influences of the calcination temperature, the initial pH of the feed solution anddegradation temperature on the activity of the RuO_2/γ-Al_2O_3 catalyst were investigated and thereaction mechanism was preliminarily studied. Results showed that uniform dispersion of RuO_2crystallites was observed on the surface of the catalyst. The activity of the catalyst was higher atcalcination temperature of 300℃ for 3 h and the particle reunion occurred and some large RuO_2crystallites were abundant at high calcination temperature of 500℃ The activity of the catalyst wasbetter in the acid solution than in the alkaline solution. Increasing degradation temperature andusing the catalyst could shorten the induction periods so that the phenol and COD removal wereincreased. For RuO_2/γ-Al_2O_3 catalyst, the phenol and COD removal were respectively 98% and 80%in a temperature of 150℃, pH of 5.6 and pressure of 3 MPa after a 2 h reaction. This indicated thatRu/γ-Al_2O_3 catalyst had good activity.

CATALYTIC BEHAVIOR OF SILICA-SUPPORTED POLY-γ- AMINOPROPYL- SILOXANE-Co-Ru BIMETALLIC COMPLEX FOR THE HYDROFORMYLATION OF CYCLOHEXENE

The cobalt and ruthenium bimetallic complex of poly-γ-amino-propylsiloxane( abbr. as Si-CH_2-Co-Ru) was prepared, and it was found that it can catalyze the hydroformylation of cyclobexene effectively with the conversion amounting to over 90%. Cyclohexanecarboxaldehyde was first formed in the hydroformylation, and then further hydrogenated to form cylcohexanemethanol. The coversion was affected obviously by the Co/Ru ratio.When Co/Ru molar ratio was 100-150, i.e. in the very low content of noble metal Ru, the catalytic activity of Si-NH_2 -Co-Ru was also very high. The product composition was affected by CO/H_2 ratio in the reaction gas. Aldehyde can be got high selectively by controlling CO/H_2 ratio. Compared with other catalyst system, the Si-NH_2-Co-Ru catalyst has higher catalytic activity and efficiency with very low Ru/Co ratio. The total turnover number was more than 28,800 (based on the amount of ruthenium used).

Protonation effect on catalytic water oxidation activity of a mononuclear Ru catalyst containing a free pyridine unit

Two efficient single-site Ru water oxidation catalysts [Ru（bda）（pic）（Ln）] （bda=2,2＇-bipyridine- 6,6＇-dicarboxylic acid, pic=picoline, Ll=4,5-bipyridine-2,7-di-tett-butyl-9,9-dimethylxanthene, L2=4- pyridine-5-phenyl-2,7-di-tert-butyl-9,9-dimethylxanthene） were only synthesized containing different xanthene ligands at the axial site. These complexes have been thoroughly characterized by spectroscopic （UV-vis, NMR） and electrochemical （CV and DIV） techniques. Kinetic analysis proved that the mechanism of water oxidation comprises the water nucleophilic attack process on high-valence ruthenium species. It is found that the catalyst I displayed higher activity than catalyst 2 on water oxidation, caused by the protonation of the axial ligand LI with a free pyridine.