Methanol Tolerant Non-noble Metal Co-C-N Catalyst for Oxygen Reduction Reaction Using Urea as Nitrogen Source

A non-noble metal oxygen reduction reaction （ORR） catalyst labeled as Co-C-N（800） was synthesized by heat-treating a mixture of urea, cobalt chloride and acetylene black for 2 h at 800 ℃ in an inert nitrogen atmosphere. X-ray diffraction pattern indicates that a metallic β-Co is generated after the heat-treating process. The results from cyclic voltammograms show that the obtained Co-C-N（800） catalyst has good ORR catalytic activity in 0.5 mol/L H2SO4 solution. The catalyst is also good at methanol tolerance and stability in the acidic solution.

Non-noble metals as activity sites for ORR catalysts in proton exchange membrane fuel cells (PEMFCs)

Proton exchange membrane fuel cells(PEMFCs)have great potential to become the next generation green energy technique,but their application is limited by the slow kinetics of the cathode oxygen reduction reaction(ORR)in acidic medium.Meanwhile,the high price of Pt-based catalysts,which are now widely used commercially,has raised the cost of PEMFCs.Therefore,non-noble metal ORR catalysts as alternatives to Pt-based group metals(PGM)have attracted much attention.However,there is still a big gap between the performance of non-noble metal catalysts and commercial Pt/C catalysts in acidic environment.Recently,it has been realized that the performance of catalysts is closely related to the structure of catalytically active sites.Inspired by this,in this review,we firstly introduced the development and breakthrough of non-noble metals as activity sites.We then briefly summarized their catalytic mechanisms,and put forward some suggestions on how to improve the activity and stability of non-noble metal ORR catalysts.

Theoretical insights into efficient oxygen evolution reaction using non-noble metal single-atom catalysts on W_(2)CO_(2)MXene

The pursuit of highly active oxygen evolution reaction(OER)catalysts,especially those free of noble metals,is a focal point in fuel cell research.Utilizing extensive density functional theory calculations,this study designed and evaluated the activity and stability of singleatom catalysts(SACs)composed of 3d,4d and 5d transition metals supported on tungsten-based MXene for OER applications.Results highlighted the exceptional OER performance of Ni@W_(2)CO_(2),Rh@W_(2)CO_(2)and Pt@W_(2)CO_(2),displaying remarkably low overpotentials The catalytic activity of TM@W_(2)CO_(2)SACs exhibited a robust correlation with surface properties,particularly the d-band center index and surface work function.Moreover Ni@W_(2)CO_(2),Rh@W_(2)CO_(2)and Pt@W_(2)CO_(2)emerged as promising candidates for OER and oxygen reduction reaction(ORR)bifunctional catalysis,while Pt@W_(2)CO_(2)and Rh@W_(2)CO_(2)showed high potential for OER and hydrogen evolution reaction(HER)bifunctional catalysis The effectiveness of tungsten-based MXene as a substrate for non-noble-metal SACs marks a breakthrough in OER catalyst design,driving advancements towards sustainable energy solutions and addressing critical challenges in energy conversion and storage.

Recent advances in carbonized non-noble metal–organic frameworks for electrochemical catalyst of oxygen reduction reaction

The non-noble metal oxygen reduction reaction(ORR) catalysts prepared by carbonization of metal–organic framework(MOF) have attracted more and more attentions in the fields of fuel cells and metal-air batteries due to their unique intrinsic advantages such as high catalytic activity, low price, simple synthesis and good adaptability. Different from the study of traditional high active noble metal catalysts, this review systematically summarizes recent developments on non-noble metal(Fe,Co, Cu, Ni, Mn and Mo) ORR catalysts prepared by various MOFs carbonization in different metal centers. The effects of synthesis strategies and pyrolysis conditions on the catalyst properties are discussed. Meanwhile, the key parameters of catalytic performances(including active sites, dispersed state and specific surface area) are discussed and the prospect is presented. It is expected that this review will provide effective guidance for future studies on carbonized non-noble MOFs for ORR electrochemical catalyst.

Comparative Studies of Non-noble Metal Modified Mesoporous M-Ni-CaO-ZrO2 （M=Fe, Co, Cu） Catalysts for Simulated Biogas Dry Reforming

The present work is aimed to improve the performance of Ni-based catalysts for biogas dry reforming by adding a second non-noble metal （Fe, Co, Cu） into a previously studied mesoporous Ni-CaO-ZrO2 nanocomposite. Biogas was simulated with equivalent methane and carbon dioxide for the dry reforming reaction. X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, N2 adsorption, temperature-programmed reduction （TPR）, thermogravi- metric analysis （TGA）, and transmission electron microscopy （TEM） measurements were taken to characterize the structural and textual properties of the bimetallic catalysts as well as the accumulated carbon deposition. The addition of Fe leads to a less ordering growth of mesopores of Fe-Ni-CaO-ZrO2 sample, and the existence of Cu results in a relatively larger portion of free NiO in Cu-Ni-CaO-ZrO2. Compared with Fe and Cu, the presence of Co could efficiently form a beneficial dual metal effect and enhance the strong metal support interaction between Ni and CaO-ZrO2, thus enhancing the activity and stability of the catalyst in biogas dry reforming reaction.

Non-noble metal single-atom catalysts with phosphotungstic acid(PTA)support:A theoretical study of ethylene epoxidation

Geometric and electronic structures of phosphotungstic acid(PTA)supported single transition metal atom(Fe,Co,Ni,Ru,Rh,Pd,Os,Ir and Pt)catalysts have been systematically investigated by using the first-principles theoretical methods.Possible reaction mechanism for ethylene epoxidation was explored.The most possible anchoring site for the single transition metal atom is the fourfold hollow site on PTA.As the non-noble metal Fe1-PTA system possesses considerable adsorption energies towards both O2 and C2H4,the strong bonding interaction between Fe1 and PTA cluster was analyzed.It is found that the electron transfers from Fe atom to PTA cluster and strong covalent metal-support interactions(CMSI)between the Fe 3 d orbitals and O 2 p orbitals of PTA lay the foundation of high stability.The proposed catalytic reaction mechanism for ethylene epoxidation on Fe1-PTA single-atom catalyst(SAC)includes three steps:the O2 adsorbs on Fe1-PTA via electron transfer;the first ethylene attacks the adsorbed O2 molecule on Fe1-PTA followed by the formation of C2H4O;finally,the O atom remained on Fe1-PTA reacts with a second ethylene to form the product and accomplish the catalytic cycle.The Fe1-PTA has high selectivity and catalytic activity for ethylene epoxidation via an Eley–Rideal mechanism with low energy barriers.A potentially competitive pathway for the formation of acetaldehyde is not kinetically favorable.These results provide insights for the development of highly efficient heterogeneous SACs for ethylene epoxidation with non-noble metals.

Hierarchical structured CoP nanosheets/carbon nanofibers bifunctional eletrocatalyst for high-efficient overall water splitting

The design of efficient,stable,and economical electrocatalysts for oxygen and hydrogen evolution reaction(OER and HER)is a major challenge for overall water splitting.Herein,a hierarchical structured CoP/carbon nanofibers(CNFs)composite was successfully synthesized and its potential application as a high-efficiency bifunctional electrocatalyst for overall splitting water was evaluated.The synergetic effect of two-dimensional(2D)CoP nanosheets and on e-dimensi on al(1D)CNFs endowed the CoP/CNFs composites with abundant active sites and rapid electron and mass transport pathways,and thereby significantly improved the electrocatalytic performances.The optimized CoP/CNFs delivered a current density of 10 mA cm^(-2) at low overpotential of 325 mV for OER and 225 mV for HER.In the overall water splitting,CoP/CNFs achieved a low potential of 1.65 V at 10 mA cm^(-2).The facile strategy provided in the present work can facilitate the design and development of multifunctional non-noble metal catalysts for energy applications.

Stability and activity of carbon nanofiber-supported catalysts in the aqueous phase reforming of ethylene glycol

Nickel, cobalt, copper and platinum nanoparticles supported on carbon nano-fibers were evaluated with respect to their stability, catalytic activity and selectivity in the aqueous phase reforming of ethylene glycol （230 ℃, autogenous pressure, batch reactor）. The initial surface-specific activities for ethylene glycol reforming were in a similar range but decreased in the order of Pt （15.5 h-1 ） 〉Co（13.0 h 1 ） 〉Ni（5.2 h-1） while the Cu catalyst only showed low dehydrogenation activity. The hydrogen molar selectivity decreased in the order of Pt （53%）〉Co（21%）〉Ni （15%） as a result of the production of methane over the latter two catalysts. Over the Co catalyst acids were formed in the liquid phase while alcohols were formed over Ni and Pt. Due to the low pH of the reaction mixture, especially in the case of Co （as a result of the formed acids）, significant cobalt leaching occurs which resulted in a rapid deactivation of this catalyst. Investigations of the spent catalysts with various techniques showed that metal particle growth is responsible for the deactivation of the Pt and Ni catalysts. In addition, coking might also contribute to the deactivation of the Ni catalyst.

A Low-Cost and Easily Prepared Manganese Carbonate as an Effi cient Catalyst for Aerobic Oxidation of 5-Hydroxymethylfurfural to 2,5-Diformylfuran

A low-cost and easily prepared manganese carbonate(Mn CO_3) has been synthesized for catalytic conversion of 5-hydroxymethylfurfural(5-HMF) to 2,5-diformylfuran(DFF). The properties and morphology of the manganese carbonate were measured by SEM,XRD,TGA,BET and XPS. In this method,no harsh reaction conditions were required,and it was a simple and green process for the oxidation of 5-HMF into DFF. To achieve an optimum DFF yield,different reaction conditions,including reaction temperature,reaction time,catalyst amount,and solvents were investigated. Results from the experiments indicated that the highest DFF yield of 86.9% was obtained at 120 °C under atmospheric oxygen pressure after 6h. Finally,Mn CO_3 could be used at least five times with considerable stability.

Progress on Platinum-Based Catalyst Layer Materials for H_(2)-PEMFC

The constant increase in energy demand and related environmental issues have made fuel cells an attractive technology as an alternative to conventional energy technologies.Like any technology,fuel cells face drawbacks that scientific society has been focused on to improve and optimize the overall technology.Thus,the cost is the main inhibitor for this technology due to the significantly high cost of the materials used in catalyst layers.The current discussion mainly focuses on the fundamental electrochemical half-cell reaction of hydrogen oxidation reaction(HOR)and oxygen reduction reaction(ORR)that are taking place in the catalyst layers consisting of Platinum-based and Platinum-non noble metals.For this purpose,studies from the literature are presented and analyzed by highlighting and comparing the variations on the catalytic activity within the experimental catalyst layers and the conventional ones.Furthermore,an economic analysis of the main platinum group metals(PGMs)such as Platinum,Palladium and Ruthenium is introduced by presenting the economic trends for the last decade.

Metal–Organic Framework-Derived Hollow Nanocubes as Stable Noble Metal-Free Electrocatalyst for Water Splitting at High Current Density

Alkaline water electrolysis is an environmentally friendly and promising approach to produce hydrogen.However,high cost,low efficiency,and poor stability are roadblocks to commercialization of electrocatalysts.This work aims to design and develop a highly efficient,durable,and cost-effective electrocatalyst toward water splitting through modifying metal–organic frameworks.The electrocatalytic performance and stability surpass those of noble metal benchmarks at high current density(1–10 A·cm^(−2)).Theoretical calculations and in situ Raman spectra reveal the electronic structure of the synthesized catalyst and the mechanism of the catalytic reaction process,which rationalizes that the high catalytic activity and stability at high current are attributed to the unique electronic structure of cobalt regulated by copper and the protection provided by carbon nanotubes formed in situ,respectively.In addition,this paper proposes that the desorption ability of the catalyst toward the products(H_(2)and O_(2)),rather than the adsorption ability toward the reactants(H^(+)or OH^(−)),is more important to the sustainable and stable electrochemical water splitting progress at high current density,which is a kinetic rather than thermodynamic dominating process.The findings provide alternative insights to design and employ high performance catalysts to fuel hydrogen production as a clean energy source to tackle the global energy crisis.

Electrochemical removal of ammonium nitrogen in high efficiency and N_(2) selectivity using non-noble single-atomic iron catalyst

Ammonia nitrogen (NH_(4)^(+)-N) is a ubiquitous environmental pollutant,especially in offshore aquaculture systems.Electrochemical oxidation is very promising to remove NH_(4)^(+)-N,but suffers from the use of precious metals anodes.In this work,a robust and cheap electrocatalyst,iron single-atoms distributed in nitrogen-doped carbon (Fe-SAs/N-C),was developed for electrochemical removal of NH_(4)^(+)-N from in wastewater containing chloride.The FeSAs/N-C catalyst exhibited superior activity than that of iron nanoparticles loaded carbon(Fe-NPs/N-C),unmodified carbon and conventional Ti/IrO_(2)-TiO_(2)-RuO_(2)electrodes.And high removal efficiency (>99%) could be achieved as well as high N_(2)selectivity (99.5%) at low current density.Further experiments and density functional theory (DFT) calculations demonstrated the indispensable role of single-atom iron in the promoted generation of chloride derived species for efficient removal of NH_(4)^(+)-N.This study provides promising inexpensive catalysts for NH_(4)^(+)-N removal in aquaculture wastewater.

Co-Mo/γ-Al_2O_3非贵金属高效脱氧催化剂的研究

通过等体积浸渍法制备了Co Mo/γ Al2O3非贵金属脱氧催化剂。利用XRD、SEM EDS和TEM等进行了表征,并进行了常压微反脱氧装置试验。结果表明,在原料中氧体积分数为0.1%、空速3000～12000h-1、活性温度80℃以上的条件下,尾气中残氧体积分数小于1.0×10-6。300h连续运转表明,该脱氧剂具有良好的活性稳定性。

TO-3贵金属脱氧催化剂的开发和工业应用

开发了一种适用于合成气、高含量CO、乙烯、富烃气、高纯氢气等气源的TO-3贵金属脱氧催化剂。该催化剂低温活性好、选择性高,使用空速高(～6000 h-1),可将原料气中0.002%～1.0%的氧脱除至(1～10)×10-6(V/V)以下,且与CO副反应少。多种实际工况条件下的应用表明,TO-3贵金属脱氧催化剂性能优异、稳定性好。

Co-Mo/γ-Al_2O_3耐硫脱氧催化剂的TPD-TPR研究

采用等体积浸渍法制备了Co-Mo/γ-Al2O3非贵金属耐硫脱氧催化剂,在实验室微反装置上进行了脱氧活性考评,利用程序升温脱附法(TPD)对该脱氧剂H2、O2的脱附行为进行了研究;同时,利用程序升温还原法(TPR)对新鲜样及中试失活样进行了研究。结果表明,在该催化剂上H2存在两个脱附峰,对应有两种吸附活化位;O2有四个脱附峰,对应有四种吸附活化位,水汽吸附会优先占据弱吸附活性位,从而抑制了其对H2和O2的活化吸附量。催化剂有三种耗氢还原峰,峰面积呈肥胖型,且在各个温度下都有还原,活性组份Co-Mo与Al2O3之间协同作用,直接影响着催化剂脱氧活性,新鲜样中的活性物种与载体间的作用要比失活样的强。研究结果对Co-Mo/γ-Al2O3非贵金属耐硫脱氧催化剂的使用、失活和再生有重要的意义。

金属脱氧剂对乙烯气氛中氧脱除性能的研究

对TKY-1、TKY-2和TKY-3三种不同类型金属脱氧剂在富含乙烯气体中对氧深度脱除的性能进行了研究,通过比较,确定TKY-1脱氧剂为较佳的催化剂。在TKY-1脱氧剂上考察了脱氧温度对脱氧效果的影响,以及脱氧压力、空速对脱氧温度的影响。当脱氧精度(残氧体积分数)为1×10-6时,确定了TKY-1在富乙烯气氛中的脱氧操作温度,为回收炼厂气乙烯资源成套技术脱氧装置的设计提供了基础数据。

工业混合气脱氧剂研究现状

工业混合气中的许多有价值气体常因氧气含量较高而不能循环利用,甚至容易导致燃爆,给工业生产带来安全问题。随着对环境保护和节能减排的重视,工业混合气脱氧催化剂的研究越来越重要,并具有广阔的应用前景和市场前景。对工业中使用较为普遍的催化脱氧、化学吸附脱氧和活性炭高温脱氧方式进行介绍,概述混合气脱氧剂类型,混合气脱氧剂包括贵金属脱氧催化剂和非贵金属脱氧催化剂,介绍非贵金属脱氧催化剂中的铜系、镍系、锰系、钼系和铁系脱氧催化剂,并对今后混合气脱氧剂的研究方向进行展望。贵金属脱氧催化剂较昂贵,非贵金属型脱氧催化剂已成为主流,各种非贵金属脱氧催化剂将成为主要研究对象。

Ce_(0.5)Zr_(0.5)O_2修饰的Ni/SiC、Fe/SiC和Co/SiC催化燃烧甲烷性能(英文)

以铈锆固溶体(Ce0.5Zr0.5O2)修饰的高比表面积SiC为载体,采用两步浸渍法制备了Ni、Fe和Co基催化剂,研究了其在煤层气催化燃烧脱氧中的催化活性和稳定性.利用X射线衍射(XRD)、X射线光电子能谱(XPS)、电感耦合等离子体质谱(ICP-MS)、高分辨透射电子显微镜(HRTEM)、比表面积(BET)、热重分析(TGA)和H2程序升温还原(H2-TPR)对催化剂进行了表征.分析结果表明,Ni、Fe和Co部分进入Ce0.5Zr0.5O2固溶体晶格内部,导致催化剂体相形成更多的缺陷;同时Ce0.5Zr0.5O2固溶体有助于加速金属氧化物和金属之间氧化还原过程的进行,促进了氧吸附、传输和对甲烷的活化.另外,SiC和Ce0.5Zr0.5O2固熔体良好的抗积碳性能,有效避免了催化剂在富甲烷反应气氛中因积碳而失活,从而使三种催化剂均具有优良的催化燃烧脱氧活性和稳定性.其中,Co/Ce0.5Zr0.5O2/SiC活性最高,可在320℃活化催化甲烷,并在410℃实现完全脱氧.

Density functional theory calculations on single atomic catalysis:Ti-decorated Ti3C2O2 monolayer(MXene)for HCHO oxidation

Formaldehyde(HCHO) is a common indoor pollutant, long-term exposure to HCHO may harm human health. Its efficient removal at mild conditions is still challenging. The catalytic oxidation of HCHO molecules on a single atomic catalyst, Ti-decorated Ti3C2O2(Ti/Ti3C2O2) monolayer, is investigated by performing the first principles calculations in this work. It demonstrates that Ti atoms can be easily well dispersed at the form of single atom on Ti3C2O2 monolayer without aggregation. For HCHO catalytic oxidation, both Langmuir-Hinshelwood(LH) and Eley-Rideal(ER) mechanisms are considered. The results show that the step of HCHO dissociative adsorption on Ti/Ti3C2O2 with activated O2 can release high energy of 4.05 e V based on the ER mechanism, which can help to overcome the energy barrier(1.04 e V) of the subsequent reaction steps. The charge transfer from *OH group to CO molecule(dissociated from HCHO) not only promotes *OH group activation but also plays an important role in the H2 O generation along the ER mechanism. Therefore, HCHO can be oxidized easily on Ti/Ti3C2O2 monolayer, this work could provide significant guidance to develop effective non-noble metal catalysts for HCHO oxidation and broaden the applications of MXene-based materials.

Test factors affecting the performance of zinc–air battery

Zinc-air batteries provide a great potential for future large-scale energy storage.We assess the test factors that mainly affect the measured power density of the zinc-air battery.By fitting the polarization curves of the zinc-air batteries,we reveal the effect of testing parameters(electrode distance,electrolyte concentration,and oxygen flux)and preparation of catalysts ink on the activation,ohm,and concentration polarizations of the zinc-air battery.Finally,recommendations on evaluating the potentials of non-noblemetal electrocatalysts for applications in zinc-air batteries were given.