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Enhancing alkyne semi-hydrogenation through engineering metal-support interactions of Pd on oxides

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Nano Research 2024年第5期17卷 3707-3713页

作者： Yuefeng Wu Xiaotong Lu Pengfei Cui Wenyu Jia Jun Zhou Yuan Wang Hussain Zahid Yuxin Wu Muhammad Umer Rafique Xiong Yin Baoshan Li Leyu Wang Guolei Xiang State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China CAS Key Laboratory of Science and Technology on Applied Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China College of Chemical Engineering Beijing University of Chemical TechnologyBeijing 100029China

supported Pd catalysts show superior activities for olefin productions from alkynes through semi-hydrogenation reactions,but over-hydrogenation into alkanes highly decreases olefin selectivity.Using phenylacetylene semi-hydrogenation as a model reaction,here we explore the optimization approaches toward better Pd catalysts for alkyne semi-hydrogenation through investigating support effect and metal-support interactions.The results show that the states of Pd with supports can be tuned by varying oxide reducibility,loading ratios,and post-treatments.In our system,0.06 wt.%Pd on rutile-TiO_(2) nanorods shows the highest activity owing to the synergistic effects of single-atoms and clusters.support reducibility can change the filling degrees of Pd 4d orbitals through varying interfacial bonding strengths,which further affect catalytic activity and selectivity.

关键词： alkyne semi-hydrogenation support effect metal-support interaction Pd catalyst single-atom catalyst

Aqueous-phase reforming of hydroxyacetone solution to bio-based H_(2)over supported Pt catalysts

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Green Energy & Environment 2024年第4期9卷 777-788页

作者： A.K.K.Vikla K.Koichumanova Songbo He K.Seshan Joint International Research Laboratory of Circular Carbon Nanjing Tech UniversityNanjing211816China Faculty of Science and Technology University of Twente7500 AE EnschedeThe Netherlands CoRe Pro 9723 BL GroningenThe Netherlands

Aqueous-phase reforming(APR)is an attractive process to produce bio-based hydrogen from waste biomass streams,during which the catalyst stability is often challenged due to the harsh reaction conditions.In this work,three Pt-based catalysts supported on C,AlO(OH),and ZrO_(2)were investigated for the APR of hydroxyacetone solution in afixed bed reactor at 225℃and 35 bar.Among them,the Pt/C catalyst showed the highest turnover frequency for H_(2)production(TOF of 8.9 molH_(2)molPt^(-1)min^(-1))and the longest catalyst stability.Over the AlO(OH)and ZrO_(2)supported Pt catalysts,the side reactions consuming H_(2),formation of coke,and Pt sintering result in a low H_(2)production and the fast catalyst deactivation.The proposed reaction pathways suggest that a promising APR catalyst should reform all oxygenates in the aqueous phase,minimize the hydrogenation of the oxygenates,maximize the WGS reaction,and inhibit the condensation and coking reactions for maximizing the hydrogen yield and a stable catalytic performance.

关键词： APR Hydroxyacetone TOF Bio-based H_(2) support effect

Docking MOF crystals on graphene support for highly selective electrocatalytic peroxide production

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Nano Research 2022年第1期15卷 145-152页

作者： Xiaofeng Huang Peter Oleynikov Hailong He Alvaro Mayoral Linqin Mu Feng Lin Yue-Biao Zhang School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China Department of Chemistry Virginia TechBlacksburgVA 24061USA

Tailoring the reaction kinetics is the central theme of designer electrocatalysts,which enables the selective conversion of abundant and inert atmospheric species into useful products.Here we show a supporting effect in tuning the electrocatalytic kinetics of oxygen reduction reaction(ORR)from four-electron to two-electron mechanism by docking metalloporphyrin-based metal-organic frameworks(MOFs)crystals on graphene support,leading to highly selective peroxide production with faradaic efficiency as high as 93.4%.A magic angle of 38.1°tilting for the co-facial alignment was uncovered by electron diffraction tomography,which is attributed to the maximization of n-n interaction for mitigating the lattice and symmetry mismatch between MOF and graphene.The facilitated electron migration and oxygen chemisorption could be ascribed to the supportive effect of graphene that disperses of the electron state of the active center,and ultimately regulates rate-determining step.

关键词： metal-organic frameworks nanocomposites support effect oxygen reduction reaction peroxide selectivity

Numerical Experiment for support effect of Umbrella Arch in Tunnel

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Numerical Experiment for Support Effect of Umbrella Arch in ...

Design concept for electrocatalysts

作者： Yuwen Wang Zhao Hu Yongli Xie Chao Wang Kaicheng Hua Jinxing Lai Hongpeng Lai Guangdong Huiqing Expressway Co. Ltd. School of Highway Chang’an University

Umbrella arch is often used as pre-support for shallow tunnel and poor surrounding rock.To evaluate the support effect quantitatively,12 cases by numerical analysis were used to study the effect of cover depth and condition of surrounding rock on the support effect of umbrella arch.Load percentage of umbrella arch was proposed to evaluate the effectiveness of umbrella arch.The umbrella arch could not work when the percentage was less than 50%.When the surrounding rock was poor and the shallower the cover depth,the better the support effect.

关键词： Tunnel Engineering Umbrella Arch support effect Numerical Experiment Evaluation

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Nano Research 2022年第3期15卷 1730-1752页

作者： Yao Wang Xiaobo Zheng Dingsheng Wang Department of Chemistry Tsinghua UniversityBeijing 100084China

Metal-based electrocatalysts with different sizes(single atoms,nanoclusters,and nanoparticles)show different catalytic behaviors for various electrocatalytic reactions.Regulating the coordination environment of active sites with precision to rationally design an efficient electrocatalyst is of great significance for boosting electrocatalytic reactions.This review summarizes the recent process of heterogeneous supported single atoms,nanoclusters,and nanoparticles catalysts in electrocatalytic reactions,respectively,and figures out the construct strategies and design concepts based on their strengths and weaknesses.Specifically,four key factors for enhancing electrocatalytic performance,including electronic structure,coordination environment,support property,and interfacial interactions are proposed to provide an overall comprehension to readers in this field.Finally,some insights into the current challenges and future opportunities of the heterogeneous supported electrocatalysts are provided.

关键词： electrocatalysts electronic structure coordination environment support effect interfacial interactions

Insights into support effects on Ce-Zr-O mixed oxide-supported gold catalysts in CO oxidation

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Journal of Energy Chemistry 2013年第1期22卷 98-106页

作者： Hongpeng Zhang Haichao Liu Beijing National Laboratory for Molecular Sciences State Key Laboratory for Structural Chemistry of Stable and Unstable Species College of Chemistry and Molecular Engineering Peking University

Au]Cel_xZrxO2 catalysts （x = 0-0.8） were prepared by a deposition-precipitation method using Cel_xZrxO2 nanoparticles as supports with variable Ce and Zr contents. Their structures were characterized by complimentary means such as X-ray diffraction, Raman, scanning trans- mission electron microscopy and X-ray photoelectron spectroscopy （XPS）. These Au catalysts possessed similar sizes and crystalline phases of Cel_xZrzO2 supports as well as similar sizes and oxidation states of Au nanoparticles. The oxidation state of Au nanoparticles was dominated by Au~ especially in CO oxidation. Their activities were examined in CO oxidation at different temperatures in the range of 303-333 K. The CO oxidation rates normalized per Au atoms increased with the increasing Ce contents, and reached the maximum value over Au/CeO2. Such change was in parallel with the change in the oxygen storage capacity values, i.e. the amounts of active oxygen species on Au/Cel_zZrzO2 catalysts. The excellent correlation between the two properties of the catalysts suggests that the intrinsic support effects on the CO oxidation rates is related to the effects on the adsorption and activation of O2 on Au/Cel_xZrxO2 catalysts. Such understanding on the support effects may be useful for designing more active Au catalysts, for example, by tuning the redox properties of oxide supports.

关键词： gold catalyst ceria-zirconia support CO oxidation oxygen storage capacity support effect

The support effect on the size and catalytic activity of thiolated Au25 nanoclusters as precatalysts

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The support effect on the size and catalytic activity of thi...

Efficient hydrogen production through the chemical looping redox cycle of YSZ supported iron oxides

中国化学会第30届学术年会-第十五分会：表界面结构调控...

作者： Jun Fang Yang Yang Jianping Xie Ning Yan State Key Laboratory of Materials-Oriented Chemical Engineering Nanjing Tech University Department of Chemical and Biomolecular Engineering National University of Singapore

Thiolate-protected Au nanoclusters(or thiolated Au NCs) are very promising catalysts due to their well-defined cluster size(atomic precision) and structure(atomically resolved).So thiolated Au NCs provide an ideal platform to reveal certain fundamental issues related to Au-based catalytic reactions.In this study,6-mercaptohexanoic(MHA) protected Au25(MHA)18 nanoclusters(or thiolated Au NCs) deposited on various inorganic supports,including hydroxyapatite(HAP),TiO(Degussa P25),activated carbon(AC),pyrolyzed graphene oxide(PGO),and fumed SiO were prepared via a conventional impregnation method.Following that,calcination under a N2 stream was conducted to produce surface ligand-free,highly dispersed Au NCs catalysts.The effects of supports on the size and catalytic activity of Au NCs were systematically investigated.Both the size effect and metal–support interaction are crucial for the design of supported Au NCs as efficient catalysts for targeted reactions.

关键词： Au25 nanoclusters heterogeneous catalysis size effect support effect

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Green Energy & Environment 2021年第6期6卷 875-883页

作者： Li Ma Yu Qiu Min Li Dongxu Cui Shuai Zhang Dewang Zeng Rui Xiao Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy and EnvironmentSoutheast UniversityNanjing210096China

The chemical looping process,where an oxygen carrier is reduced and oxidized in a cyclic manner,offers a promising option for hydrogen production through splitting water because of the much higher water splitting efficiency than solar electrocatalytic and photocatalytic process.A typical oxygen carrier has to comprise a significant amount of inert support,to maintain stability in multiple redox cycles,thereby resulting in a trade-off between the reaction reactivity and stability.Herein,we proposed the use of ion-conductive yttria-stabilized zirconia(YSZ)support Fe_(2)O_(3)to prepare oxygen carriers materials.The obtained Fe_(2)O_(3)/YSZ composites showed high reactivity and stability.Particularly,Fe_(2)O_(3)/YSZ-20(oxygen storage capacity,24.13%)exhibited high hydrogen yield of~10.30 mmol g^(-1) and hydrogen production rate of~0.66 mmol g^(-1) min^(-1) which was twice as high as that of Fe_(2)O_(3)/Al_(2)O_(3).Further,the transient pulse test indicated that active oxygen diffusion was the ratelimiting step during the redox process.The electrochemical impedance spectroscopy(EIS)measurement revealed that the YSZ support addition facilitated oxygen diffusion of materials,which contributed to the improved hydrogen production performance.The support effect obtained in this work provides a potentially efficient route for the modification of oxygen carrier materials.

关键词： Hydrogen production Chemical looping Oxygen carriers support effect

Enhancing both selectivity and coking-resistance of a single-atom Pd1/C3N4 catalyst for acetylene hydrogenation

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Nano Research 2017年第4期10卷 1302-1312页

作者： Xiaohui Huang Yujia Xia Yuanjie Cao Xusheng Zheng Haibin Pan Junfa Zhu Chao Ma Hengwei Wang Junjie Li Rui You Shiqiang Wei Weixin Huang Junling Lu Department of Chemical Physics iChEM CAS Key Laboratory of Materials for Energy Conversion University of Science and Technology of China Hefei 230026 China National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei 230029 China Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China Hefei 230026 China

Selective hydrogenation is an important industrial catalytic process in chemical upgrading, where Pd-based catalysts are widely used because of their high hydrogenation activities. However, poor selectivity and short catalyst lifetime because of heavy coke formation have been major concerns. In this work, atomically dispersed Pd atoms were successfully synthesized on graphitic carbon nitride （g-C3N4） using atomic layer deposition. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy （HAADF-STEM） confirmed the dominant presence of isolated Pd atoms without Pd nanoparticle （NP） formation. During selective hydrogenation of acetylene in excess ethylene, the g-C3N4-supported Pd NP catalysts had strikingly higher ethylene selectivities than the conventional Pd/Al2O3 and Pd/SiO2 catalysts. In-situ X-ray photoemission spectroscopy revealed that the considerable charge transfer from the Pd NPs to g-C3N4 likely plays an important role in the catalytic performance enhancement. More impressively, the single-atom Pd1/C3N4 catalyst exhibited both higher ethylene selectivity and higher coking resistance. Our work demonstrates that the single-atom Pd catalyst is a promising candidate for improving both selectivity and coking-resistance in hydrogenation reactions.

关键词： single-atom catalyst Pd catalyst atomic layer deposition acetylene hydrogenation C3N4 selectivity coke formation support effect