Production of Mixed Alcohols from Bio-syngas over Mo-based Catalyst

A series of Mo-based catalysts prepared by sol-gel method using citric acid as complexant were successfully applied in the high efficient production of mixed alcohols from bio-syngas, derived from the biomass gasification. The Cu1Co1Fe1MO1Zn0.5-6%K catalyst exhibited a higher activity on the space-time yield of mixed alcohols, compared with the other Mobased catalysts. The carbon conversion significantly increases with rising temperature below 340 ℃, but the alcohol selectivity has an opposite trend. The maximum mixed alcohols yield derived from biomass gasification is 494.8 g/（kg catal·h） with the C2＋ （C2-C6 higher alcohols） alcohols of 80.4% under the tested conditions. The alcohol distributions are consistent with the Schulz-Flory plots, except methanol. In the alcohols products, the C2＋ alcohols （higher alcohols） dominate with a weight ratio of 70%-85%. The Mo-based cata- lysts have been characterized by X-ray diffraction and N2 adsorption/desorption. The clean bio-fules of mixed alcohols derived from bio-syngas with higher octane values could be used as transportation fuels or petrol additives.

Effects of Activation Atmospheres on Structure and Activity of Mo-based Catalyst for Synthesis of Higher Alcohols

Activated carbon supported Mo-based catalysts were prepared and reduced under different activation atmospheres, including pure H2, syngas （H2/CO=2/1）, and pure CO. The cat- alysts structures were characterized by X-ray diffraction , X-ray absorption fine structure, and in situ diffuse reflectance infrared Fourier transform spectroscopy. The catalytic per- formance for the higher alcohol synthesis from syngas was tested. The pure H2 treatment showed a high reduction capacity. The presence of a large amount of metallic CoO and low valence state Mo^φ＋ （0〈φ〈2） on the surface suggested a super activity for the CO dissoci- ation and hydrogenation, which promoted hydrocarbons formation and reduced the alcohol selectivity. In contrast, the pure CO-reduced catalyst had a low reduction degree. The Mo and Co species at the catalyst mainly existed in the form of Mo^4＋ and Co^2＋. The syngas- reduced catalyst showed the highest activity and selectivity for the higher alcohols synthesis. We suggest that the syngas treatment had an appropriate reduction capacity that is between those of pure H2 and pure CO and led to the coexistence of multivalent Co species as well as the enrichment of Mo~＋ on the catalyst＇s surface. The synergistic effects between these active species provided a better cooperativity and equilibrium between the CO dissociation, hydrogenation and CO insertion and thus contributed beneficially to the formation of higher alcohols.

Hydrogenation Conversion of Phenanthrene over Dispersed Mo-based Catalysts

With oil-soluble molybdenum compound and sublimed sulfur serving as raw materials, two dispersed Mo-based catalysts were prepared, characterized and then applied to the hydrogenation conversion of phenanthrene. The test results showed that under the conditions specified by this study, the catalyst prepared in a higher sulfiding atmosphere was more catalytically active due to its higher content of MoS2 and stronger intrinsic catalytic activity of MoS2 unit, which demonstrated that the sulfiding atmosphere for the preparation of catalysts not only could influence the yield of MoS2 but also the structure of MoS2.The analysis on the selectivity of octahydrophenanthrene isomers revealed that the catalyst prepared in a lower sulfiding atmosphere had a relatively higher catalytic selectivity to the hydrogenation of outer aromatic ring and the structure of catalysts could be modified under the specific reaction conditions. Moreover, the selectivity between the isomers of as-octahydrophenanthrene at different reaction time and temperature was analyzed and, based on the results, a hydrogenation mechanism over dispersed Mo-based catalysts was suggested, with monatomic hydrogen transfer and catalytic surface desorption of the half-addition intermediates functioning as the key points. In addition, it is concluded that the catalyst prepared in a lower sulfiding atmosphere was more capable of adsorption than the other one.

Potassium-decorated active carbon supported Co-Mo-based catalyst for water-gas shift reaction

The effect of potassium-decoration was studied on the activity of water-gas shift （WGS） reaction over the Co-Mo-based catalysts supported on active carbon （AC）, which was prepared by incipient wetness co-impregnation method. The decoration of potassium on active carbon in advance enhances the activities of the CoMo-K/AC catalysts for WGS reaction. Highest activity （about 92% conversion） was obtained at 250 ？ C for the catalyst with an optimum K 2 O/AC weight ratio in the range from 0.12 to 0.15. The catalysts were characterized by TPR and EPR, and the results show that activated carbon decorated with potassium makes Co-Mo species highly dispersed, and thus easily reduced and sulfurized. XRD results show that an appropriate content of potassium-decoration on active carbon supports may favors the formation of highly dispersed Co 9 S 8 -type structures which are situated on the edge or a site in contact with MoS 2 , K-Mo-O-S, Mo-S-K phase. Those active species are responsible for the high activity of CoMo-K/AC catalysts.

Selective Oxidation of Toluene with Hydrogen Peroxide Catalyzed by V-Mo-based Catalyst

The selective catalytic oxidation of toluene with hydrogen peroxide over V-Mo-based catalysts under mild conditions was studied.The promotion effect of Mo on the catalysts was studied with V/Al2O3 and Mo/Al2O3 as reference samples.The catalysts were characterized by XRD,TPR,and XPS techniques.The results show that the addition of Mo to V/Al2O3 may change the distribution of V species on Al2O3 surface.Over V-Mo/Al2O3 catalyst,highly dispersed amorphous V species facilitates benzaldehyde formation,and crystalline V2O5 species increases the conversion of toluene but decreases the selectivity to benzaldehyde,while AlVMoO7 species favors both the conversion of toluene and the formation of cresols.The yield of benzaldehyde depends remarkably on the surface O/Al and Mo/V atomic ratios,and gets to a maximum value of 13.2% with a selectivity of 79.5% at an O/Al atomic ratio of 3.0 and Mo/V atomic ratio of 0.7.

Interface Engineering and Anion Engineering of Mo-Based Heterogeneous Electrocatalysts for Hydrogen Evolution Reaction

Development and utilization of hydrogen energy is an effective way to achieve carbon neutrality,only hydrogen production through electrolytic water splitting meets the goal of zero carbon emission.To facilitate the large-scale commercialization of water splitting devices,the development of highly efficient and low-cost catalysts to reduce the energy consumption is essential.MoS_(2)has been regarded as a promising electrocatalyst to replace platinum in hydrogen evolution reaction due to its low price and unique 2D layered structure.However,the poor conductivity and inert basal planes of MoS_(2)limited its wide-spread application.Recently,researches have demonstrated that the conductivity and active sites of MoS_(2)can be improved by heteroatoms doping or constructing of heterogeneous structures.In this review,the recent progress of Mo-based catalysts are summarized centered on MoS_(2)based on interface engineering and anion engineering,including MoS_(2)–MoO_(2),MoS_(2)–Mo_(2)C,MoS_(2)–MoN_(x),MoS_(2)–MoP,and MoS_(2)–MoSe_(2).The preparation method,structure,and performance of the catalysts are introduced and the possible mechanism behind the improved catalytic activity are revealed to give readers an overall comprehension on the progress of the Mo-based electrocatalysts for hydrogen evolution reaction.In addition,an outlook on future opportunities and development directions of Mo-based catalysts are proposed to facilitate the development of Mo-based catalysts for hydrogen production.

Bimetallic Single‑Atom Catalysts for Water Splitting

Green hydrogen from water splitting has emerged as a critical energy vector with the potential to spearhead the global transition to a fossil fuel-independent society.The field of catalysis has been revolutionized by single-atom catalysts(SACs),which exhibit unique and intricate interactions between atomically dispersed metal atoms and their supports.Recently,bimetallic SACs(bimSACs)have garnered significant attention for leveraging the synergistic functions of two metal ions coordinated on appropriately designed supports.BimSACs offer an avenue for rich metal–metal and metal–support cooperativity,potentially addressing current limitations of SACs in effectively furnishing transformations which involve synchronous proton–electron exchanges,substrate activation with reversible redox cycles,simultaneous multi-electron transfer,regulation of spin states,tuning of electronic properties,and cyclic transition states with low activation energies.This review aims to encapsulate the growing advancements in bimSACs,with an emphasis on their pivotal role in hydrogen generation via water splitting.We subsequently delve into advanced experimental methodologies for the elaborate characterization of SACs,elucidate their electronic properties,and discuss their local coordination environment.Overall,we present comprehensive discussion on the deployment of bimSACs in both hydrogen evolution reaction and oxygen evolution reaction,the two half-reactions of the water electrolysis process.

Catalyst–Support Interaction in Polyaniline‑Supported Ni_(3)Fe Oxide to Boost Oxygen Evolution Activities for Rechargeable Zn‑Air Batteries

Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3)Fe oxide/PANI)with a robust hetero-interface,which significantly improves oxygen evolution activities with an overpotential of 270 mV at 10 mA cm^(-2)and specific activity of 2.08 mA cm_(ECSA)^(-2)at overpotential of 300 mV,3.84-fold that of Ni_(3)Fe oxide.It is revealed that the catalyst–support interaction between Ni_(3)Fe oxide and PANI support enhances the Ni–O covalency via the interfacial Ni–N bond,thus promoting the charge and mass transfer on Ni_(3)Fe oxide.Considering the excellent activity and stability,rechargeable Zn-air batteries with optimum Ni_(3)Fe oxide/PANI are assembled,delivering a low charge voltage of 1.95 V to cycle for 400 h at 10 mA cm^(-2).The regulation of the effect of catalyst–support interaction on catalytic activity provides new possibilities for the future design of highly efficient OER catalysts.

Boosting Oxygen Evolution Reaction Performance on NiFe‑Based Catalysts Through d‑Orbital Hybridization

Anion-exchange membrane water electrolyzers(AEMWEs)for green hydrogen production have received intensive attention due to their feasibility of using earth-abundant NiFe-based catalysts.By introducing a third metal into NiFe-based catalysts to construct asymmetrical M-NiFe units,the d-orbital and electronic structures can be adjusted,which is an important strategy to achieve sufficient oxygen evolution reaction(OER)performance in AEMWEs.Herein,the ternary NiFeM(M:La,Mo)catalysts featured with distinct M-NiFe units and varying d-orbitals are reported in this work.Experimental and theoretical calculation results reveal that the doping of La leads to optimized hybridization between d orbital in NiFeM and 2p in oxygen,resulting in enhanced adsorption strength of oxygen intermediates,and reduced rate-determining step energy barrier,which is responsible for the enhanced OER performance.More critically,the obtained NiFeLa catalyst only requires 1.58 V to reach 1 A cm^(−2) in an anion exchange membrane electrolyzer and demonstrates excellent long-term stability of up to 600 h.

High Fe‑Loading Single‑Atom Catalyst Boosts ROS Production by Density Effect for Efficient Antibacterial Therapy

The current single-atom catalysts(SACs)for medicine still suffer from the limited active site density.Here,we develop a synthetic method capable of increasing both the metal loading and mass-specific activity of SACs by exchanging zinc with iron.The constructed iron SACs(h^(3)-FNC)with a high metal loading of 6.27 wt%and an optimized adjacent Fe distance of~4 A exhibit excellent oxidase-like catalytic performance without significant activity decay after being stored for six months and promising antibacterial effects.Attractively,a“density effect”has been found at a high-enough metal doping amount,at which individual active sites become close enough to interact with each other and alter the electronic structure,resulting in significantly boosted intrinsic activity of single-atomic iron sites in h^(3)-FNCs by 2.3 times compared to low-and medium-loading SACs.Consequently,the overall catalytic activity of h^(3)-FNC is highly improved,with mass activity and metal mass-specific activity that are,respectively,66 and 315 times higher than those of commercial Pt/C.In addition,h^(3)-FNCs demonstrate efficiently enhanced capability in catalyzing oxygen reduction into superoxide anion(O_(2)·^(−))and glutathione(GSH)depletion.Both in vitro and in vivo assays demonstrate the superior antibacterial efficacy of h^(3)-FNCs in promoting wound healing.This work presents an intriguing activity-enhancement effect in catalysts and exhibits impressive therapeutic efficacy in combating bacterial infections.

Preparation of Co/S co-doped carbon catalysts for excellent methylene blue degradation

S and Co co-doped carbon catalysts were prepared via pyrolysis of MOF-71 and thiourea mixtures at 800℃at a mass ratio of MOF-71 to thiourea of 1:0.1 to effectively activate peroxymonosulfate(PMS)for methylene blue(MB)degradation.The effects of two different mixing routes were identified on the MB degradation performance.Particularly,the catalyst obtained by the alcohol solvent evaporation(MOF-AEP)mixing route could degrade 95.60%MB(50 mg/L)within 4 min(degradation rate:K=0.78 min^(-1)),which was faster than that derived from the direct grinding method(MOF-DGP,80.97%,K=0.39 min^(-1)).X-ray photoelectron spectroscopy revealed that the Co-S content of MOF-AEP(43.39at%)was less than that of MOF-DGP(54.73at%),and the proportion of C-S-C in MOF-AEP(13.56at%)was higher than that of MOF-DGP(10.67at%).Density functional theory calculations revealed that the adsorption energy of Co for PMS was -2.94 eV when sulfur was doped as C-S-C on the carbon skeleton,which was higher than that when sulfur was doped next to cobalt in the form of Co-S bond(-2.86 eV).Thus,the C-S-C sites might provide more contributions to activate PMS compared with Co-S.Furthermore,the degradation parameters,including pH and MOF-AEP dosage,were investigated.Finally,radical quenching experiments and electron paramagnetic resonance(EPR)measurements revealed that ^(1)O_(2)might be the primary catalytic species,whereas·O~(2-)might be the secondary one in degrading MB.

Three-Phase Heterojunction NiMo-Based Nano-Needle for Water Splitting at Industrial Alkaline Condition

Constructing heterojunction is an effective strategy to develop high-performance non-preciousmetal-based catalysts for electrochemical water splitting(WS).Herein,we design and prepare an N-doped-carbon-encapsulated Ni/MoO_(2) nano-needle with three-phase heterojunction(Ni/MoO_(2)@CN)for accelerating the WS under industrial alkaline condition.Density functional theory calculations reveal that the electrons are redistributed at the three-phase heterojunction interface,which optimizes the adsorption energy of H-and O-containing intermediates to obtain the best ΔG_(H*) for hydrogen evolution reaction(HER)and decrease the ΔG value of ratedetermining step for oxygen evolution reaction(OER),thus enhancing the HER/OER catalytic activity.Electrochemical results confirm that Ni/MoO_(2)@CN exhibits good activity for HER(ƞ_(-10)=33 mV,ƞ_(-1000)=267 mV)and OER(ƞ_(10)=250 mV,ƞ_(1000)=420 mV).It shows a low potential of 1.86 V at 1000 mA cm^(−2) for WS in 6.0 M KOH solution at 60℃ and can steadily operate for 330 h.This good HER/OER performance can be attributed to the three-phase heterojunction with high intrinsic activity and the self-supporting nano-needle with more active sites,faster mass diffusion,and bubbles release.This work provides a unique idea for designing high efficiency catalytic materials for WS.

光学体表成像设备Catalyst的故障维修案例及日常保养方法

本文介绍了光学体表成像设备Catalyst HD的工作原理,以及处理常见的硬件和软件故障的方法,并提供了日常维护保养方法。其中,对于硬件故障,利用Catalyst HD系统的MutilZsn软件来判断Catalyst投影器和摄像头故障,对于软件故障方面,探讨了Catalyst HD系统在医用直线加速器上常见的Authorization Pending联锁问题的触发原因。本文为科室更好地开展光学体表引导放疗技术,高效地运用好设备提供参考意见。

Strong synergy between physical and chemical properties:Insight into optimization of atomically dispersed oxygen reduction catalysts

Atomically dispersed catalysts exhibit significant influence on facilitating the sluggish oxygen reduction reaction(ORR)kinetics with high atom economy,owing to remarkable attributes including nearly 100%atomic utilization and exceptional catalytic functionality.Furthermore,accurately controlling atomic physical properties including spin,charge,orbital,and lattice degrees of atomically dispersed catalysts can realize the optimized chemical properties including maximum atom utilization efficiency,homogenous active centers,and satisfactory catalytic performance,but remains elusive.Here,through physical and chemical insight,we review and systematically summarize the strategies to optimize atomically dispersed ORR catalysts including adjusting the atomic coordination environment,adjacent electronic orbital and site density,and the choice of dual-atom sites.Then the emphasis is on the fundamental understanding of the correlation between the physical property and the catalytic behavior for atomically dispersed catalysts.Finally,an overview of the existing challenges and prospects to illustrate the current obstacles and potential opportunities for the advancement of atomically dispersed catalysts in the realm of electrocatalytic reactions is offered.

Boric Acid-Assisted Pyrolysis for High-Loading Single-Atom Catalysts to Boost Oxygen Reduction Reaction in Zn-Air Batteries

The emerging of single-atom catalysts(SACs)offers a great opportunity for the development of advanced energy storage and conversion devices due to their excellent activity and durability,but the actual mass production of high-loading SACs is still challenging.Herein,a facile and green boron acid(H_(3)BO_(3))-assisted pyrolysis strategy is put forward to synthesize SACs by only using chitosan,cobalt salt and H_(3)BO_(3)as precursor,and the effect of H_(3)BO_(3)is deeply investigated.The results show that molten boron oxide derived from H_(3)BO_(3)as ideal high-temperature carbonization media and blocking media play important role in the synthesis process.As a result,the acquired Co/N/B tri-doped porous carbon framework(Co-N-B-C)not only presents hierarchical porous structure,large specific surface area and abundant carbon edges but also possesses high-loading single Co atom(4.2 wt.%),thus giving rise to outstanding oxygen catalytic performance.When employed as a catalyst for air cathode in Zn-air batteries,the resultant Co-N-B-C catalyst shows remarkable power density and long-term stability.Clearly,our work gains deep insight into the role of H_(3)BO_(3)and provides a new avenue to synthesis of high-performance SACs.

Advancements in transition bimetal catalysts for electrochemical 5-hydroxymethylfurfural(HMF) oxidation

The electrochemical oxidation of 5-hydroxymethylfurfural(HMF) represents a significant avenue for sustainable chemical synthesis, owing to its potential to generate high-value derivatives from biomass feedstocks. Transition metal catalysts offer a cost-effective alternative to precious metals for catalyzing HMF oxidation, with transition bimetallic catalysts emerging as particularly promising candidates. In this review, we delve into the intricate reaction pathways and electrochemical mechanisms underlying HMF oxidation, emphasizing the pivotal role of transition bimetallic catalysts in enhancing catalytic efficiency. Subsequently, various types of transition bimetallic catalysts are explored, detailing their synthesis methods and structural modulation strategies. By elucidating the mechanisms behind catalyst modification and performance enhancement, this review sets the stage for upcoming advancements in the field, ultimately advancing the electrochemical HMF conversion and facilitating the transition towards sustainable chemical production.

Catalytic effect in lithium metal batteries: From heterogeneous catalyst to homogenous catalyst

Lithium metal batteries are regarded as prominent contenders to address the pressing needs owing to the high theoretical capacity.Toward the broader implementation,the primary obstacle lies in the intricate multi-electron,multi-step redox reaction associated with sluggish conversion kinetics,subsequently giving rise to a cascade of parasitic issues.In order to smooth reaction kinetics,catalysts are widely introduced to accelerate reaction rate via modulating the energy barrier.Over past decades,a large amount of research has been devoted to the catalyst design and catalytic mechanism exploration,and thus the great progress in electrochemical performance has been realized.Therefore,it is necessary to make a comprehensive review toward key progress in catalyst design and future development pathway.In this review,the basic mechanism of lithium metal batteries is provided along with corresponding advantages and existing challenges detailly described.The main catalysts employed to accelerate cathode reaction with emphasis on their catalytic mechanism are summarized as well.Finally,the rational design and innovative direction toward efficient catalysts are suggested for future application in metal-sulfur/gas battery and beyond.This review is expected to drive and benefit future research on rational catalyst design with multi-parameter synergistic impacts on the activity and stability of next-generation metal battery,thus opening new avenue for sustainable solution to climate change,energy and environmental issues,and the potential industrial economy.

Towards the insights into the deactivation behavior of acetylene hydrogenation catalyst

A series of model catalysts were obtained by treating commercial fresh and spent catalysts unloaded from the factory with different methods, including green oil dipping, extraction and high-temperature regeneration;finally, the deactivation behavior of the commercial catalyst for acetylene hydrogenation were studied. The influence of various possible deactivation factors on the catalytic performance was elucidated via detailed structural characterization, surface composition analysis, and activity evaluation.The results showed that green oil, carbon deposit and sintering of active metal were the main reasons for deactivation, among which green oil and carbon deposit led to rapid deactivation, while the activity could be recovered after regeneration by high-temperature calcination. The sintering of active metal components was attributed to the high-temperature regeneration in hydrothermal conditions, which was slow but irreversible and accounted for permanent deactivation. Thus, optimizing the regeneration is expected to extend the service life of the commercial catalyst.

Formation and Oxidation Resistance of Silicide Coatings for Mo and Mo-Based Alloys

The forming process of silicide coatings on pure Mo and Mo-base alloys, obtained by the gas- phase deposition method. has been studied by examining the microstructure of coatings and the relationship between coating thickness and process parameters. It was shown that the growth of coatings was diffusion-controlled, the diffusion of silicon to be coated into Mo or Mo-base alloys was mainly responsible for the formation of silicide. The relationship between initial silicide thickness and oxidation resistance was also investigated, and the equation of service life of the coatings at high temperature in air is presented.

p-d Orbital Hybridization Engineered Single-Atom Catalyst for Electrocatalytic Ammonia Synthesis

The rational design of metal single-atom catalysts(SACs)for electrochemical nitrogen reduction reaction(NRR)is challenging.Two-dimensional metal-organic frameworks(2DMOFs)is a unique class of promising SACs.Up to now,the roles of individual metals,coordination atoms,and their synergy effect on the electroanalytic performance remain unclear.Therefore,in this work,a series of 2DMOFs with different metals and coordinating atoms are systematically investigated as electrocatalysts for ammonia synthesis using density functional theory calculations.For a specific metal,a proper metal-intermediate atoms p-d orbital hybridization interaction strength is found to be a key indicator for their NRR catalytic activities.The hybridization interaction strength can be quantitatively described with the p-/d-band center energy difference(Δd-p),which is found to be a sufficient descriptor for both the p-d hybridization strength and the NRR performance.The maximum free energy change(ΔG_(max))andΔd-p have a volcanic relationship with OsC_(4)(Se)_(4)located at the apex of the volcanic curve,showing the best NRR performance.The asymmetrical coordination environment could regulate the band structure subtly in terms of band overlap and positions.This work may shed new light on the application of orbital engineering in electrocatalytic NRR activity and especially promotes the rational design for SACs.