Compositional engineering of HKUST-1/sulfidized NiMn-LDH on functionalized MWCNTs as remarkable bifunctional electrocatalysts for water splitting

Water-splitting reactions such as the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)typically require expensive noble metal-based electrocatalysts.This has motivated researchers to develop novel,cost-effective electrocatalytic systems.In this study,a new multicomponent nanocomposite was assembled by combining functionalized multiwalled carbon nanotubes,a Cu-based metal–organic framework(MOF)(HKUST-1 or HK),and a sulfidized NiMn-layered double hydroxide(NiMn-S).The resulting nanocomposite,abbreviated as MW/HK/NiMn-S,features a unique architecture,high porosity,numerous electroactive Cu/Ni/Mn sites,fast charge transfer,excellent structural stability,and conductivity.At a current density of 10 mA cm-2,this dual-function electrocatalyst shows remarkable performance,with ultralow overpotential values of 163 mV(OER)or 73 mV(HER),as well as low Tafel slopes(57 and 75 mV dec-1,respectively).Additionally,its high turnover frequency values(4.43 s-1 for OER;3.96 s-1 for HER)are significantly superior to those of standard noble metal-based Pt/C and IrO2 systems.The synergistic effect of the nanocomposite's different components is responsible for its enhanced electrocatalytic performance.A density functional theory study revealed that the multi-interface and multicomponent heterostructure contribute to increased electrical conductivity and decreased energy barrier,resulting in superior electrocatalytic HER/OER activity.This study presents a novel vision for designing advanced electrocatalysts with superior performance in water splitting.Various composites have been utilized in water-splitting applications.This study investigates the use of the MW/HK/NiMn-S electrocatalyst for water splitting for the first time to indicate the synergistic effect between carbon-based materials along with layered double hydroxide compounds and porous compounds of MOF.The unique features of each component in this composite can be an interesting topic in the field of water splitting.

Bimetallic ZIFs-derived electrospun carbon nanofiber membrane as bifunctional oxygen electrocatalyst for rechargeable zinc-air battery

The recharged zinc-air battery(ZAB) has drawn significant attention owing to increasing requirement for energy conversion and storage devices.Fabricating the efficient bifunctional oxygen catalyst using a convenient strategy is vitally important for the rechargeable ZAB.In this study,the bimetallic ZIFs-containing electrospun(ES) carbon nanofibers membrane with hierarchically porous structure was prepared by coaxial electrospinning and carbonization process,which was expected to be a bifunctional electrocatalyst for ZABs.Owing to the formed dual single-atomic sites of Co-N_(4) and Zn-N_(4),the obtained ES-Co/ZnCNZIFexhibited the preferable performance toward oxygen reduction reaction(ORR) with E1/2of 0.857 V and JLof 5.52 mA cm^(-2),which were more than Pt/C.Meanwhile,it exhibited a marked oxygen evolution reaction(OER) property with overpotential of 462 mV due to the agglomerated metallic Co nanoparticles.Furthermore,the ZAB based on the ES-Co/Zn-CNZIFcarbon nanofibers membranes delivered peak power density of 215 mW cm^(-2),specific capacity of 802.6 mA h g^(-1),and exceptional cycling stability,far larger than Pt/C+RuO_(2)-based ZABs.A solid-state ZAB based on ES-Co/Zn-CNZIFshowed better flexibility and stability with different bending angles.

Acid‐promoted Ir‐La‐S/AC‐catalyzed methanol carbonylation on single atomic active sites

Highly active Ir‐La‐S/AC catalyst was successfully prepared by co‐impregnation of an activated carbon（AC） carrier with a sulfuric acid solution of Ir and La species and compared with a tradition‐ally prepared Ir‐La/AC catalyst. High angle annular dark‐field‐scanning transmission electron mi‐croscopy（HAADF‐STEM） measurement results show that most of the Ir species on Ir‐La‐S/AC exist as single atomic sites, while those on Ir‐La/AC exist as nanoparticles with an average diameter of 1.5 nm. Evaluation of Ir‐La‐S/AC as a catalyst for heterogeneous carbonylation of methanol to acetyl gave a maximum TOF （turn‐over‐frequency） of 2760 h^–1, which was distinctly higher than that achieved by the Ir‐La/AC catalyst（approximately 1000 h^-1）. Temperature‐programmed desorption of ammonia（NH3‐TPD） result shows that the addition of sulfuric acid during the preparation pro‐cedure results in significantly more acidic sites on Ir‐La‐S/AC than those on Ir‐La/AC, which plays a key role in the enhancement of CO insertion as the rate‐determining step. Tempera‐ture‐programmed reduction（TPR） and in situ X‐ray photoelectron spectroscopy reveal that Ir spe‐cies are more reducible, and that more Ir^＋ might be formed by activation of Ir‐La‐S/AC than those on the Ir‐La/AC catalyst, which is thought to be beneficial for reductive elimination of AcI from Ir^3＋ species as an essential step for CH3I regeneration and acetyl formation.

Facile synthesis of metal-organic frameworks embedded in interconnected macroporous polymer as a dual acid-base bifunctional catalyst for efficient conversion of cellulose to 5-hydroxymethylfurfural

5-Hydroxymethylfurfural(5-HMF),as a key platform compound for the conversion of biomass to various biomass-derived chemicals and biofuels,has been attracted extensive attention.In this research,using Pickering high internal phase emulsions(Pickering HIPEs)as template and functional metal-organic frameworks(MOFs,UiO-66-SO;H and UiO-66-NH;)/Tween 85 as co-stabilizers to synthesis the dual acid-base bifunctional macroporous polymer catalyst by one-pot process,which has excellent catalytic activity in the cascade reaction of converting cellulose to 5-HMF.The effects of the emulsion parameters including the amount of surfactant(ranging from 0.5%to 2.0%(mass)),the internal phase volume fraction(ranging from 75%to 90%)and the acid/base Pickering particles mass ratio(ranging from 0:6 to 6:0)on the morphology and catalytic performance of solid catalyst were systematically researched.The results of catalytic experiments suggested that the connected large pore size of catalyst can effectively improve the cellulose conversion,and the synergistic effect of acid and base active sites can effectively improve the 5-HMF yield.The highest 5-HMF yield,about 40.5%,can be obtained by using polymer/MOFs composite as catalyst(Poly-P12,the pore size of(53.3±11.3)μm,the acid density of 1.99 mmol·g^(-1)and the base density of 1.13 mol·g^(-1))under the optimal reaction conditions(130℃,3 h).Herein,the polymer/MOFs composite with open-cell structure was prepared by the Pickering HIPEs templating method,which provided a favorable experimental basis and theoretical reference for achieving efficient production of high addedvalue product from abundant biomass.

CoSe_(2)-CuSe_(2)NF双功能电催化剂的制备及其电解水性能的研究

随着环境污染日益严重、不可再生资源日益枯竭,对清洁、可再生能源的开发非常重要。利用电解水析氢(HER)和析氧(OER)技术生产氢气和氧气,是一种高效、无污染的制备清洁能源的方法。但是,商业贵金属电催化剂价格昂贵、地球丰度低,因此,开发价格低廉、高活性、高稳定性的非贵金属电催化剂意义重大。本研究利用水热法成功制备出一系列具有纳米花结构的双功能电催化剂(CuSe_(2)-CoSe_(2)(1∶1)NF、CuSe_(2)-CoSe_(2)(3∶1)NF、CuSe_(2)-CoSe_(2)(1∶3)NF),通过一系列的表征对催化剂的结构、形貌、元素组成、元素价态进行分析。研究发现CuSe_(2)-CoSe_(2)NF双金属硒化物中CoSe_(2)和CuSe_(2)相互协同作用,促进电子转移,提高电解水性能。此外,CuSe_(2)-CoSe_(2)NF纳米花结构具有较大的比表面积(808 m^(2)/g),暴露更多的活性位点数,进一步提升了催化剂的电化学性能。结果表明,CuSe_(2)-CoSe_(2)(1∶1)NF催化剂在1 mol/L KOH电解液、电流密度为10 mA·cm^(-2)时,HER和OER的过电位为42和204 mV,可持续稳定工作100 h,与商业Pt/C和RuO_(2)性能接近。

Atomic Co/Ni dual sites with N/P-coordination as bifunctional oxygen electrocatalyst for rechargeable zinc-air batteries

Metal-nitrogen-carbon(M-N-C)single-atom catalysts exhibit desirable electrochemical catalytic properties.However,the replacement of N atoms by heteroatoms(B,P,S,etc.)has been regarded as a useful method for regulating the coordination environment.The structure engineered M-N-C sites via doping heteroatoms play an important role to the adsorption and activation of the oxygen intermediate.Herein,we develop an efficient strategy to construct dual atomic site catalysts via the formation of a Co_(1)-PN and Ni1-PN planar configuration.The developed Co_(1)-PNC/Ni1-PNC catalyst exhibits excellent bifunctional electrocatalytic performance in alkaline solution.Both experimental and theoretical results demonstrated that the N/P coordinated Co/Ni sites moderately reduced the binding interaction of oxygen intermediates.The Co_(1)-PNC/Ni1-PNC endows a rechargeable Zn-air battery with excellent power density and cycling stability as an air-cathode,which is superior to that of the benchmark Pt/C+IrO_(2).This work paves an avenue for design of dual single-atomic sites and regulation of the atomic configuration on carbon-based materials to achieve high-performance electrocatalysts.

Carbon nanotube supported bifunctional electrocatalysts containing iron-nitrogen-carbon active sites for zinc-air batteries

Bifunctional electrocatalysts with high activity toward both oxygen reduction and evolution reaction are highly desirable for rechargeable Zn-air batteries. Herein, a kind of carbon nanotube (CNT) supported single-site Fe-N-C catalyst was fabricated via pyrolyzing in-situ grown Fe-containing zeolitic imidazolate frameworks on CNTs. CNTs not only serve as the physical supports of the Fe-N-C active sites but also provide a conductive network to facilitate the fast electron and ion transfer. The as-synthesized catalysts exhibit a half-wave potential of 0.865 V for oxygen reduction reaction and a low overpotential of 0.442 V at 10 mA·cm^(−2) for oxygen evolution, which is 310 mV smaller than that of Fe-N-C without CNTs. The rechargeable Zn-air batteries fabricated with such hybrid catalysts display a high peak power density of 182 mW·cm^(−2) and an excellent cycling stability of over 1,000 h at 10 mA·cm^(−2), which outperforms commercial Pt-C and most of the reported catalysts. This facile strategy of combining single-site Metal-N-C with CNTs network is effective for preparing highly active bifunctional electrocatalysts.

Aerophilic Triphase Interface Tuned by Carbon Dots Driving Durable and Flexible Rechargeable Zn‑Air Batteries

Efficient bifunctional catalysts for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are vital for rechargeable Zn-air batteries(ZABs).Herein,an oxygen-respirable sponge-like Co@C–O–Cs catalyst with oxygen-rich active sites was designed and constructed for both ORR and OER by a facile carbon dot-assisted strategy.The aerophilic triphase interface of Co@C–O–Cs cathode efficiently boosts oxygen diffusion and transfer.The theoretical calculations and experimental studies revealed that the Co–C–COC active sites can redistribute the local charge density and lower the reaction energy barrier.The Co@C–O–Cs catalyst displays superior bifunctional catalytic activities with a half-wave potential of 0.82 V for ORR and an ultralow overpotential of 294 mV at 10 mA cm^(−2) for OER.Moreover,it can drive the liquid ZABs with high peak power density(106.4 mW cm^(−2)),specific capacity(720.7 mAh g^(−1)),outstanding long-term cycle stability(over 750 cycles at 10 mA cm^(−2)),and exhibits excellent feasibility in flexible all-solid-state ZABs.These findings provide new insights into the rational design of efficient bifunctional oxygen catalysts in rechargeable metal-air batteries.

合成气制混合醇双功能催化研究进展

混合醇合成要求催化剂具备至少两类活性中心, 一类用于解离吸附CO以生成烷基链, 另一类用于非解离吸附CO以使烷基链含氧化生成醇. 两类中心通过协同作用共同构成混合醇合成所需的双活性中心. 简要综述了近年来合成气制混合醇过程中涉及的双功能催化研究进展, 并以几类典型的催化剂体系为例, 从双活性中心的构筑、典型的双活性中心结构、反应过程中双活中心结构的演变等方面进行了阐述. 混合醇催化剂的研发应从纳米尺度上对催化剂进行设计, 使催化剂表面具有足够多的双活性中心, 并设法稳定催化剂的双活性中心结构.

异构化催化剂Pd／HM结炭失活研究

本文研究了正己烷异构化反应中双功能催化剂Ｐｄ／ＨＭ的结炭部位及反应条件、反应时间对催化剂结炭的影响。结果表明：催化剂金属和酸性中心均有结炭现象，金属中心先结炭，且比酸中心上结炭容易除去。两中心上结炭数量及除去难度都随反应条件的变化而增加，尤其是酸中心，这一现象与延长反应时间带来的影响是一致的。

人肿瘤坏死因子与人γ干扰素重组双功能融合蛋白的研制

肿瘤坏死因子与γ干扰素具有非常相似的生物学活性,并在一些主要的生物活性方面表现有较强的协同作用。本文采用寡核苷酸指导下的定位缺失-插入体外基因突变技术,删除了干扰素与肿瘤坏死因子串联基因之间的非编码区,去徐了γ干扰素的翻译终止信号,插入了一个人工设计的连接肽,使γ干扰素与肿瘤坏死因子基因在不改变读码框架的条件下融合起来,并在大肠杆菌表达系统中表述了兼有γ干扰素和肿瘤坏死因子功能的融合蛋白。

Self-templated nitrogen-doped mesoporous carbon decorated with double transition-metal active sites for enhanced oxygen electrode catalysis

The development of high-performance,low-cost bifunctional catalysts with long-term stability for the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is one of the most critical challenges for the large-scale application of metal-air batteries.Herein,we report an advanced nitrogen-doped mesoporous carbon(NMC)composite(NiCo2O4/CoNx-NMC)formed from a mixture of Co-and Ni-hydroxide-infiltrated phenolic resin and melamine resin.This composite exhibits superior electrocatalytic activity,stability,and selectivity for the ORR and OER.The activity parameter(DE),which is an indicator of the overall catalytic activity of bifunctional catalysts,was 0.76 V for NiCo2O4/CoNx-NMC.Therefore,catalyst outperforms the majority of previously reported non-precious metal-based bifunctional electrocatalysts.The remarkable ultra-high catalytic performance of NiCo2O4/CoNx-NMC for the ORR and OER can be attributed to the presence of different active sites of the CoNx structure and the formation of NiCo2O4 with the spinel structure,which was obtained by a stepwise pyrolysis process.This synthesis strategy opens a new avenue for the rational design of highly active bifunctional electrocatalysts.

Determining hydrothermal deactivation mechanisms on Cu/SAPO-34 NH_(3)-SCR catalysts at low-and high-reaction regions:establishing roles of different reaction sites

Hydrothermal deactivation is a constant chal-lenge in commercial catalytic process aimed at NOx emission control,which may be observed in the low(150-400℃)or high(400-550℃)-reaction regions.To the best of our knowledge,there is a lack of systematic research regarding the correlation between the reaction sites and the mechanism of hydrothermal degradation at various reaction regions.For a targeted investigation of this,Cu/zeolite catalysts have been prepared using different amounts of polyvinyl alcohol for adjusting their redox and acid properties.These catalysts exhibit hydrothermal deactivation in different reaction regions.No change is observed in the reaction mechanism even with hydrother-mal deactivation,but various reaction sites determine the performance deterioration in the low-and high-reaction regions.The redox properties and weak acid sites affect the hydrothermal deactivation in the low-reaction region,whereas the moderate/strong acid sites related to the structure mainly influence the hydrothermal deactivation in the high-reaction region.This work provides several the-oretical insights for optimizing the hydrothermal stabilities of Cu/zeolite catalysts.

Tuning the dual-active sites of ZIF-67 derived porous nanomaterials for boosting oxygen catalysis and rechargeable Zn-air batteries

The rational control of the active site of metal-organic frameworks(MOFs)derived nanomaterials is essential to build efficient bifunctional oxygen reduction/evolution reaction(ORR/OER)catalysts.Accordingly,through designing and constructing a Co_(3)O_(4)-Co heterostructure embedded in Co,N co-doped carbon polyhedra derived(Co_(3)O_(4)-Co@NC)from the in-situ compositions of ZIF-67 and cobalt nanocrystals synthesized by the strategy of in-situ NaBH4 reduction,the dual-active site(Co_(3)O_(4)-Co and Co-N_(x))is synchronously realized in a MOFs derived nanomaterials.The formed Co_(3)O_(4)-Co@NC shows excellent bifunctional electrocatalytic activity with ultra-small potential gap(ΔE=E_(j=10)(OER)–E_(1/2)(ORR))of 0.72 V,which surpasses the commercial Pt/C and RuO_(2) catalysts.The theory calculation results reveal that the excellent bifunctional electrocatalytic activity can be attributed to the charge redistribution of Co of Co-N_(x) induced by the synergistic effects of well-tuned active sites of Co_(3)O_(4)-Co nanoparticle and Co-N_(x),thus optimizing the rate-determining step of the desorption of O_(2)^(*)intermediate in ORR and OH^(*)intermediate in OER.The rechargeable Zn-air batteries with our bifunctional catalysts exhibit superior performance as well as high cycling stability.This simple-effective optimization strategy offers prospects for tuning the active site of MOF derived bifunctional catalyst in electrochemical energy devices.

Efficient oxygen electrocatalysts with highly-exposed Co-N4 active sites on N-doped graphene-like hierarchically porous carbon nanosheets enhancing the performance of rechargeable Zn-air batteries

Designing bifunctional oxygen electrocatalysts with high activity,lasting stability,and low-cost for rechargeable zinc-air batteries(RZABs)is a tough challenge.Herein,an advanced electrocatalyst is prepared by anchoring atomically dispersed Co atoms on Ndoped graphene-like hierarchically porous carbon nanosheets(SA-Co-N4-GCs)and thereby forming Co-N4-C architecture.Its unique structure with excellent conductivity,large surface area,and three dimensional(3D)interconnected hierarchically porous architecture exposes not only more Co-N4 active sites to accelerate the kinetics of both oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),but also provides an efficient charge/mass transport environment to reduce diffusion barrier.Consequently,SA-Co-N4-GCs exhibits excellent ORR/OER bifunctional activities and durability,surpassing noble-metal catalysts.Liquid RZABs using SA-Co-N4-GCs cathodes display a high open-circuit voltage of 1.51 V,a remarkable power density of 149.3 mW·cm−2,as well as excellent stability and rechargeability with faint increase in polarization even at a large depth of charge–discharge cycle with 16 h per cycle over an entire 600 h long-term test.Moreover,flexible quasi-solid-state RZABs with SA-Co-N4-GCs cathodes also deliver a considerable power density of 124.5 mW·cm−2,which is even higher than that of liquid batteries using noble-metal catalysts.This work has thrown new insight into development of high-performance and low-cost electrocatalysts for energy conversion and storage.

含CuSBA-15催化剂的合成、表征及DeNPAC反应性能评价

采用浸渍法和离子交换法合成了CuO／SBA～15、CuAl／SBA-15和CuOAl／SBA-153种催化剂。SBA-15的酸功能通过负载Al而得以改进。通过浸渍法和离子交换法将Cu引入SBA-15和A1／SBA-15中。3种催化剂相比，CuAl／SBA-15在DeNPAC反应中具有最高的吡啶转化率的同时，具有最低的NOx产率。CuAl／SBA-15具有较好的含氮多环芳烃化合物脱除反应性能的原因，可能是其酸功能和金属离子功能共同作用的结果。

Some insight on the structure/activity relationship of metal nanoparticles in Cu/SiO2 catalysts

The activity of two Cu/SiO2 catalysts prepared by the chemisorption hydrolysis technique has been tested in the hydrogenation reaction of 3-methyl-cyclohexanone. Both catalysts were found to be very active at 60 ℃ and 1 atm of H2. Characterization of the materials by FT-IR of adsorbed CO and TEM put in light the presence of well formed Cu cristallites. By assuming a cuboctahedral model we could show that the hydrogenation activity is linked to high coordination sites on the metal particle. A comparison is also reported with a sample prepared by ammonia evaporation that was found to be inactive in the hydrogenation reaction under the same experimental conditions.

具有不同活性中心的固体催化剂的失活模式(英文)

An approach is suggested to distinguish different types of active sites responsible for different reactions on bifunctional catalysts.The model assumes a non-uniform vulnerability of active sites that depends on their location.Problems on the relationship between the dispersion of the active phase and selectivity are discussed.The effect of coke formation on the activity change of different sites is analyzed.

3D layer-by-layer amorphous MoS_(x) assembled from[Mo_(3)S_(13)]^(2-)clusters for efficient removal of tetracycline:Synergy of adsorption and photo-assisted PMS activation

Peroxymonosulfate(PMS)activation and photocatalysis are effective technologies to remove organic pollutants,but the adsorption effect of the catalyst is usually unheeded in degradation process.Herein,a bifunctional catalyst of amorphous MoS_(x)(a-MoS_(x))with 3D layer-by-layer superstructure was synthesized by assembling basic active units[Mo_(3)S_(13)]^(2-)of MoS_(2).The large interlayer spacing and high exposure of active sites render a-MoS_(x)to have excellent synergy of adsorption and photo-assisted PMS activation for tetracycline(TC)degradation.Experiments and DFT calculation show that TC can be efficiently enriched on a-MoS_(x)by pore filling,π-πinteraction,hydrogen bonding and high adsorption energy.Subsequently,PMS can be quickly activated through electron transfer with a-MoS_(x),resulting in high TC degradation efficiency of 96.6%within 20 min.In addition,the synergistic mechanism of adsorption and photo-assisted PMS activation was explored,and the degradation pathway of TC was expounded.This work is inspirational for constructing bifunctional catalysts with superior synergistic adsorption and catalytic capabilities to remove refractory organic pollutants in water.

Ga-O双功能位点促进高选择性光催化甲烷直接转化制甲醇

光催化甲烷(CH_(4))直接转化制甲醇(CH_(3)OH)被誉为催化界的“圣杯反应”.然而,由于反应过程中目标产物容易发生过氧化反应,实现CH_(3)OH的定向转化仍然面临巨大挑战.本文通过溶剂热法和高温煅烧法成功地制备了不同晶相的Ga_(2)O_(3)光催化材料(α-Ga_(2)O_(3)和β-Ga_(2)O_(3)),并对其光催化CH_(4)直接转化制CH_(3)OH的性能进行评价.测试结果显示在室温常压,且不额外添加其他氧化剂的情况下,α-Ga_(2)O_(3)和β-Ga_(2)O_(3)表现出优异的光催化性能.相较于β-Ga_(2)O_(3),α-Ga_(2)O_(3)的光催化性能更优:反应2 h后,其CH_(4)转化率达4.5%,CH_(3)OH的生成速率与选择性分别高达372.8μmol/(g h)和82.7%.通过原位红外光谱(in situ DRIFTS)和原位电子自旋共振谱(in situ EPR)对反应机理进行了分析,发现Ga_(2)O_(3)的Ga和O分别是活化CH_(4)和水分子(H_(2)O)的活性位点.得益于Ga-O双功能活性位点的协同作用,CH_(4)和H_(2)O活化产生的·CH_(3)和·OH可以直接结合,促进了CH_(3)OH的定向生成.由于α-Ga_(2)O_(3)比β-Ga_(2)O_(3)展现出更强的活化H_(2)O的能力,α-Ga_(2)O_(3)表现出更优异的光催化CH_(4)直接转化制CH_(3)OH性能.本文为设计高效的CH_(4)直接转化制CH_(3)OH催化材料打开了新的思路.