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Boosting faradaic efficiency of CO_(2)electroreduction to CO for Fe-NC single-site catalysts by stabilizing Fe^(3+)sites via F-doping

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Nano Research 2022年第9期15卷 7896-7902页

作者： Yiqun Chen Guochang Li Yu Zeng Lijie Yan Xizhang Wang Lijun Yang Qiang Wu Zheng Hu key laboratory of mesoscopic chemistry of moe and Jiangsu Provincial lab for Nanotechnology School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China

The atomically dispersed Fe^(3+)sites of Fe-N-C single-site catalysts(SSCs)are demonstrated as the active sites for CO_(2)electroreduction(CO_(2)RR)to CO but suffer from the reduction to Fe^(2+)at~−0.5 V,accompanied by the drop of CO faradaic efficiency(FECO)and deterioration of partial current(JCO).Herein,we report the construction of F-doped Fe-N-C SSCs and the electron-withdrawing character of fluorine could stabilize Fe3+sites,which promotes the FECO from the volcano-like highest value(88.2%@−0.40 V)to the high plateau(>88.5%@−0.40-−0.60 V),with a much-increased JCO(from 3.24 to 11.23 mA·cm^(−2)).The enhancement is ascribed to the thermodynamically facilitated CO_(2)RR and suppressed competing hydrogen evolution reaction,as well as the kinetically increased electroactive surface area and improved charge transfer,due to the stabilized Fe^(3+)sites and enriched defects by fluorine *** finding provides an efficient strategy to enhance the CO_(2)RR performance of Fe-N-C SSCs by stabilizing Fe^(3+).

关键词： carbon dioxide electroreduction iron-nitrogen-carbon single-site catalysts fluorine-doping active site regulation

Review on photocatalytic and electrocatalytic artificial nitrogen fixation for ammonia synthesis at mild conditions: Advances,challenges and perspectives

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Nano Research 2019年第6期12卷 1229-1249页

作者： Xiaolan Xue Renpeng Chen Changzeng Yan Peiyang Zhao Yi Hu Wenjun Zhang Songyuan Yang Zhong Jin key laboratory of mesoscopic chemistry of moe School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China

The ammonia synthesis from nitrogen and water under ambient conditions is one of the most inviting but challenging reaction *** nitrogen is abundant in the atmosphere and the ammonia synthesis reaction is exothermic on the thermodynamics,the conversion of N2 to ammonia is actually hard to proceed owing to the chemical inertness and stability of N2 *** industry,ammonia synthesis is carried out by the Haber-Bosch process under harsh conditions (300-500 ℃,20-30 MPa) associated with the requirement of substantial energy input and the enormous emission of greenhouse gases (e.g.,CO2).Recently,a growing number of studies on photo(electro)catalytic and electrocatalytic nitrogen reduction reaction (NRR) in aqueous solution have attracted extensive attention,which holds great promise for nitrogen fixation under room temperature and atmospheric ***,the very low efficiency and ambiguous mechanism still remain as the major hurdles for the development of photochemical and electrochemical NRR *** we provide an overview of the latest progresses,remaining challenges and future prospects in photocatalytic and electrocatalytic nitrogen ***,this review offers a helpful guidance for the reasonable design of photocatalysts and electrocatalysts towards NRR by combining theory predictions and experiment *** hope this review can stimulate more research interests in the relatively understudied but highly promising research field of NRR.

关键词： heterogeneous catalysis nitrogen fixation ammonia synthesis photocatalytic electrocatalytic nitrogen reduction

Ni–Al composite hydroxides fabricated by cation–anion double hydrolysis method for high-performance supercapacitor

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Chinese Chemical Letters 2016年第4期27卷 507-510页

作者： Shuang-Shuang Yang Ming-Jiang Xie Yu Shen Yong-Zheng Wang Xue-Feng Guo Bin Shen School of chemistry and Chemical Engineering Southeast University key lab of mesoscopic chemistry moe School of Chemistry and Chemical EngineeringNanjing University

Chemical doping of nickel hydroxide with other cations（e.g. Al^（3＋）） is an efficient way to enhance its electrochemical capacitive performances. Herein, a simple cation–anion（Ni^（2＋）and AlO_2） double hydrolysis method was developed toward the synthesis of nickel–aluminum（Ni–Al） composite hydroxides. The obtained composite hydroxides possesses a porous structure, large surface area（121 m^2/g） and homogeneous element distribution. The electrochemical test shows that the obtained composite hydroxides exhibits a superior supercapacitive performances（specific capacitance of 1670F/g and rate capability of 87% from 0.5 A/g to 20 A/g） to doping-free nickel hydroxide（specific capacitance of 1227 F/g and rate capability of 47% from 0.5 A/g to 20 A/g）. Moreover, the galvanostatic charge/discharge test displays that after 2000 cycles at large current density of 10 A/g, the composite hydroxides achieves a high capacitance retention of 98%, indicative of an excellent electrochemical cycleability.

关键词： Nanocomposites Porous materials Double hydrolysis Doped Ni(OH)2 Energy storage

Core-shell structured Ru-Ni@SiO_2: Active for partial oxidation of methane with tunable H_2/CO ratio

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Journal of Energy chemistry 2018年第3期27卷 883-889页

作者： Yixuan Dou Yijun Pang Lingli Gu Yifan Ding Wu Jiang Xinzhen Feng Weijie Ji Chak-Tong Au key laboratory of mesoscopic chemistry MOE School of Chemistry and Chemical Engineering Nanjing University Department of chemistry Hong Kong Baptist University

This study demonstrated that a Ru-Ni bimetallic core-shell catalyst（0.6%Ru-Ni）@Si O2with a proper surface Ru concentration is superior in achieving better catalytic activity and tunable H2/CO ratio at a comparatively lower reaction temperature（700℃）.Compared to the impregnation method,the hydrothermal approach leads to a highly uniform Ru distribution throughout the core *** Ru distribution would result in a proper surface Ru concentration as well as more direct Ru-Ni interaction,accounting for better catalyst *** surface Ru species hinders surface carbon deposition,but also declines overall activity and H2/CO ratio,meanwhile likely enhances Ni oxidation to certain degree under the applied reaction *** the current（m%Ru-Ni）@Si O2catalyst,the formation of fibrous carbon species is suppressed,which accounts for good stability of catalyst within a TOS of 10 h.

关键词： Ruthenium Nicolet Bimetallic Core-shell structure Partial oxidation of methane

Micro-interface enhanced mass transfer sodium carbonate absorption carbon dioxide reaction

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Chinese Journal of Chemical Engineering 2023年第12期64卷 208-223页

作者： Hu Shen Yingyu Xu Jigang An Bowen Jiang Jinnan Sun Guoqiang Yang Zhibing Zhang key laboratory of mesoscopic chemistry of Ministry of Education(moe) School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China

Micro-interface intensified reactor(MIR)can be applied in series/parallel in the absorption of CO_(2)in industrial gases by Na_(2)CO_(3)due to the ability to produce large numbers of stable *** work focuses on the variation pattern of mass transfer characteristics parameters of the reaction gas in Na_(2)CO_(3) solution under the influence of different solution properties and operating parameters in the reaction of CO_(2)absorption by *** mass transfer characteristics parameters include bubble Sauter mean diameter,gas holdup,interfacial area,liquid side mass transfer coefficient,and liquid side volume mass transfer coefficient *** solution properties and operating parameters include Na2CO3 concentration(0.05–2.0 mol·L^(-1)),superficial gas velocity(0.00221–0.01989 m·s^(-1)),superficial liquid velocity(0.00332–0.02984 m·s^(-1)),and ionic strength(1.42456–1.59588 mol·kg^(-1)).And volumetric mass transfer coeffi-cients kLa and superficial reaction rates r of the MIR and the bubble column reactor are compared in the reaction of sodium carbonate absorption of carbon dioxide,and the former shows a greater improvement under different solution properties and operating *** enhanced role of MIR in mass transfer in non-homogeneous reactions is verified and the feasibility of industrial practical applications of MIR is demonstrated.

关键词： Carbon dioxide Absorption Microbubble Bubble Sauter mean diameter Interfacial area Mass transfer

Promotional effect of CO pretreatment on CuO/CeO_2 catalyst for catalytic reduction of NO by CO

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Journal of Rare Earths 2014年第2期32卷 139-145页

作者：顾贤睿李昊刘礼晨汤常金高飞董林 key laboratory of mesoscopic chemistry of moe School of Chemistry and Chemical EngineeringNanjing University Center of Modern Analysis Nanjing University

The CuO/CeO2 catalysts were investigated by means of X-ray diffraction （XRD）, laser Raman spectroscopy （LRS）, X-ray photoelectronic spectroscopy （XPS）, temperature-programmed reduction （TPR）, in situ Fourier transform infrared spectroscopy （FTIR） and NO＋CO reaction. The results revealed that the low temperature （〈150℃） catalytic performances were enhanced for CO pretreated samples. During CO pretreatment, the surface Cu＋/Cu0 and oxygen vacancies on ceria surface were present. The low va- lence copper species activated the adsorbed CO and surface oxygen vacancies facilitated the NO dissociation. These effects in turn led to higher activities of CuO/CeO2 for NO reduction. The current study provided helpful understandings of active sites and reaction mechanism in NO＋CO reaction.

关键词： CuO/CeO2 catalysts CO pretreatment oxygen vacancies NO reduction rare earths

Hierarchical carbon nanocages as high-rate anodes for Li-and Na-ion batteries

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Nano Research 2015年第11期8卷 3535-3543页

作者： Zhiyang Lyu Lijun Yang Dan Xu Jin Zhao Hongwei Lai Yufei Jiang Qiang Wu Yi Li Xizhang Wang Zheng Hu key laboratory of mesoscopic chemistry of moe School of Chemistry and Chemical Engineering Nanjing University Nanjing 210093 China

Novel hierarchical carbon nanocages （hCNCs） are proposed as high-rate anodes for Li- and Na-ion batteries. The unique structure of the porous network for hCNCs greatly favors electrolyte penetration, ion diffusion, electron conduction, and structural stability, resulting in high rate capability and excellent cyclability. For lithium storage, the corresponding electrode stores a steady reversible capacity of 970 mAh·g^-1 at a rate of 0.1 A·g^-1 after 10 cycles, and stabilizes at 229 mAh·g^-1 after 10,000 cycles at a high rate of 25 A·g^-1（33 s for full-charging） while delivering a large specific power of 37 kW·kgelectrode^-1 and specific energy of 339 Wh·kgelectrode^-1. For sodium storage, the hCNC reaches a high discharge capacity of -50 mAh·g^-1 even at a high rate of 10 A·g^-1.

关键词： hierarchical carbon nanocages lithium-ion batteries sodium-ion batteries anode high rate capability

Unravelling the critical role of surface Nafion adsorption in Ptcatalyzed oxygen reduction reaction by in situ electrical transport spectroscopy

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Science China chemistry 2022年第11期65卷 2290-2298页

作者： Yamei Sun Jingyi Tian Zhangyan Mu Bailin Tian Qiulan Zhou Cheng Liu Shengtang Liu Qiang Wu Mengning Ding key laboratory of mesoscopic chemistry of moe State Key Laboratory of Analytical Chemistry for Life SciencesSchool of Chemistry and Chemical EngineeringNanjing UniversityNanjing210023China

Solid-state ionic conductor is a vital part in all electrochemical energy conversion devices. As a widely-applied protonconducting polymer and stabilizer for electrode preparation, Nafion has key applications in electrochemical devices operated under acidic conditions. Specific adsorption of Nafion on the catalyst surface is considered to result in partial loss of intrinsic activity in reactions such as oxygen reduction reaction(ORR), due to its comprehensive occupation of active sites. Many in situ characterization methods such as voltammetric fingerprinting and spectroscopic approaches have been used to explore the dynamic adsorption of Nafion on the electrode surface. However, most of current efforts have been focused on the behaviors of Nafion itself, with little attention paid to its effects on the adsorption of surface intermediates. Here, we employed the in situ electrical transport spectroscopy(ETS) to investigate Nafion adsorption on Pt catalysts and its effects on the ORR *** findings suggest that specific adsorption of Nafion results in the increased coverage of oxygen intermediates with weaker adsorption strength, which in turn plays a critical role in the reaction selectivity. The successful application of ETS on the dynamic characterization of reaction intermediates provides a novel perspective for catalyst design in ORR-related applications in future sustainable chemistry.

关键词： electrical transport spectroscopy Nafion adsorption oxygen reduction reaction platinum hydrogen peroxide

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Ultrasmall high-entropy alloy nanoparticles on hierarchical N-doped carbon nanocages for tremendous electrocatalytic hydrogen evolution

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Nano Research 2024年第11期17卷 9518-9524页

作者： Manman Jia Jietao Jiang Jingyi Tian Xizhang Wang Lijun Yang Qiang Wu Zheng Hu key laboratory of mesoscopic chemistry of moe and Jiangsu Provincial laboratory for Nanotechnology School of Chemistry and Chemical Engineering Nanjing University Nanjing 210023 China

High-entropy alloys (HEAs) are promising candidates for the electrocatalyst of hydrogen evolution reaction (HER) due to their unique properties such as cocktail electronic effect and lattice distortion effect. Herein, the ultrasmall (sub-2 nm) nanoparticles of PtRuCoNiCu HEA with uniform element distribution are highly dispersed on hierarchical N-doped carbon nanocages (hNCNC) via low-temperature thermal reduction, denoted as us-HEA/hNCNC. The optimal us-HEA/hNCNC exhibits excellent HER performance in 0.5 M H_(2)SO4 solution, achieving an ultralow overpotential of 19 mV at 10 mA·cm^(−2) (without iR-compensation), high mass activity of 13.1 A·mgnoble metals ^(−1) at −0.10 V and superb stability with a slight overpotential increase of 3 mV after 20,000 cycles of cyclic voltammetry scans, much superior to the commercial Pt/C (20 wt.%). The combined experimental and theoretical studies reveal that the Pt&Ru serve as the main active sites for HER and the CoNiCu species modify the electron density of active sites to facilitate the H* adsorption and achieve an optimum M-H binding energy. The hierarchical pore structure and N-doping of hNCNC support also play a crucial role in the enhancement of HER activity and stability. This study demonstrates an effective strategy to greatly improve the HER performance of noble metals by developing the HEAs on the unique hNCNC support.

关键词： high-entropy alloys acidic hydrogen evolution ultrasmall nanoparticles hierarchical carbon nanocages high activity