ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Xue Zhao,Changjun Xiang,Fulin Zhang,Fengze Yao,Ruiqing Sheng,Qiong Ding,Wenjing Liu,Haibo Zhang,Xiaohai Zhou
The increasing global demands for eco-friendly and low-cost catalysts have propelled the advent of nanosized non-noble-metal catalysts to replace traditional noble metals. In this work, ultrafine NiO nanoparticles were prepared rapidly in situ by the strategy of transforming three-dimensional (3D) metal boron organic polymers (BOPs@Ni2+) to one-dimensional (1D) boron organic polymers (BOPs@Ni) nanorod arrays at room temperature. The 3D BOPs@Ni2+ can be quickly obtained by the interaction of 4,4′-bipyridine with Ni2+ and dodecaborate (B12H122–) in an aqueous solution. When Ni2+ is converted into NiO in situ, 1D BOPs@Ni nanostructure transformation from the 3D BOPs@Ni2+ framework was achieved due to the B–H···π interaction between B12H122– and 4,4′-bipyridine. Furthermore, BOPs@Ni exhibits high catalytic activity and rapid kinetics in the conversion of 4-nitrophenol to 4-aminophenol, and the high stability of 1D nanorod arrays guarantees the catalytic activity of BOP@Ni to barely change under recycling for at least 10 times. BOPs@Ni also exhibits good catalytic performance and high selectivity characteristics in the catalytic reduction of a series of nitrobenzene derivatives. This strategy of using BOPs@Ni2+ for loading self-supporting nanometal not only exhibits a highly efficient catalytic hydrogenation of nitrobenzene and its derivative but also provides an effective technical route for designing self-supported nanometal materials.
研究领域:
材料化学
·
纳米技术
·
催化
·
绿色化学
·
高分子科学
✓ 已验证
DOI
高影响因子
ENERGY CONVERSION AND MANAGEMENT
·
2019
·
IF 7.181
Zhong Ma,Shuai Zhang,Rui Xiao
The Fe 2 O 3 -Al 2 O 3 oxygen carrier is regarded to a promising candidate for chemical looping combustion (CLC). However, Fe 2 O 3 -Al 2 O 3 oxygen carrier was often subjected to a decrease of oxygen carrying capacity. The deactivation mechanism of Fe 2 O 3 -Al 2 O 3 oxygen carrier in chemical looping combustion was investigated over consecutive 20 cycles. The Fe 2 O 3 -Al 2 O 3 oxygen carrier exhibited relatively poor redox stability in a fixed bed reactor. The physico-chemical properties of cycled Fe 2 O 3 -Al 2 O 3 oxygen carrier were characterized by different characterization methods. No carbon deposit was detected in the reduction process, indicating that carbon deposition was not the cause for Fe 2 O 3 -Al 2 O 3 oxygen carrier deactivation under this experimental condition. The characterization results showed that the deactivation of Fe 2 O 3 -Al 2 O 3 oxygen carrier in redox cycles was mainly attributed to thermal sintering. The cycled Fe 2 O 3 -Al 2 O 3 oxygen carrier showed lower surface area, lower reducibility and oxygen mobility than that of fresh sample. After a certain number of redox cycles, Fe diffusion and enrichment at the surface of cycled oxygen carrier was observed. The surface Fe is unstable under high reaction temperature, leading to accelerate thermal sintering. A deactivation mechanism of Fe 2 O 3 -Al 2 O 3 oxygen carrier in CLC was proposed based on the Fe diffusion and surface sintering.
研究领域:
化学工程
·
能源技术
·
材料科学
·
催化
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2017
·
IF 7.504
Lu-Nan Zhang,Si-Heng Li,Hua-Qiao Tan,Shifa Ullah Khan,Yuan-Yuan Ma,Hong-Ying Zang,Yong-Hui Wang,Yang-Guang Li
During the exploration of highly efficient noble-metal-free electrocatalysts for the hydrogen evolution reaction (HER), a promising and challenging strategy is to fabricate composite nanocatalysts by finely tuning metal and/or nonmetal element components. Herein, we report a new HER electrocatalyst, which is composed of molybdenum phosphide and molybdenum carbide composite nanoparticles (NPs) coated by few-layer N-doped graphitic carbon shells (denoted as MoP/Mo2C@C). Such a new combination mode of electrocatalysts is realized by a one-step annealing route with the mixture of a Mo/P-based polyoxometalate (POM) and dicyandiamide. On the basis of this method, the simultaneous phosphorization and carbonization in a nanoscale confined space can be easily achieved by the use of POM as the molecular-element-regulating platform. MoP/Mo2C@C exhibits more remarkable HER performance over the whole pH range than those of MoP, Mo2C, and the physical mixture of MoP and Mo2C. The low overpotentials of 89, 136, and 75 mV were obtained at a current density of 10 mA cm–2 in the media of pH = 0, 7, and 14, respectively. Furthermore, MoP/Mo2C@C shows a long-term durability for 14 h over the entire pH range (0–14). Because of the protection of carbon shells, such composite electrocatalyst also possesses better transition-metal tolerance exemplified by Fe2+, Co2+, and Ni2+ than that of 20% commercial Pt/C. This work demonstrates the advantage of POM precursors in adjusting the component and properties of nanoscale composite electrocatalysts for HER, which may suggest new options for the fabrication of highly efficient composite electrocatalysts.
研究领域:
电化学
·
材料科学
·
催化
·
能量转换
·
纳米材料
✓ 已验证
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2017
·Vol. 19
·期 28
·18232-18242
·
IF 4.123
Samrat Devaramani,Mahgoub Ibrahim Shinger,Xiaofang Ma,Meng Yao,Shouting Zhang,Dongdong Qin,Xiaoquan Lu
J- and H-aggregates of zinc tetraphenylporphyrin (ZnTPP) on carbon nanotube films (CNTFs) were prepared using the mixed solvent method. This resulted in completely different structures, such as the four-leaf clover and flower, on the CNTF, which were observed by recording SEM images. Characteristic changes in the electronic spectra of the ZnTPP monomer appeared when it underwent J- and H-aggregation. The measured photocurrent significantly varied for the same molecule when it was aggregated in two different ways on ITO and ITO/CNTF. The electron recombination resistance of the two aggregates, which was investigated using electrochemical impedance spectroscopy, was also different. The photocatalytic efficiency of the J- and H-aggregates was examined by performing methylene blue dye decoloration studies. In addition, a scanning electrochemical microscope was used to investigate the photoinduced charge transfer kinetics of the J- and H-aggregates at the electrode/electrolyte interface as a fresh attempt. The heterogeneous charge transfer constants for the J- and H-aggregates in the presence of light at varied intensities were calculated. Thereby, striking differences in the photophysical, photocatalytic, and photoelectrochemical properties of the J- and H-aggregates were visualized throughout our studies.
研究领域:
材料科学
·
光化学
·
纳米技术
·
电化学
·
可再生能源
·
催化
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2018
·
IF 6.945
Xiaodeng Wang,Hongpeng Zhou,Dingke Zhang,Mingyu Pi,Jiajia Feng,Shijian Chen
Developing stable and high-efficiency hydrogen generation electrocatalysts , particularly for the cathode hydrogen evolution reaction (HER), is an urgent challenge in energy conversion technologies. In this work, we have successfully synthesized Mn-doped NiP 2 nanosheets on carbon cloth (Mn-NiP 2 NSs/CC), which behaves as a higher efficient three dimensional HER electrocatalyst with better stability at all pH values than pure NiP 2 . Electrochemical tests demonstrate that the catalytic activity of NiP 2 is enhanced by Mn doping. In 0.5 M H 2 SO 4 , this Mn−NiP 2 NSs/CC catalyst drives 10 mA cm −2 at an overpotential of 69 mV, which is 20 mV smaller than pure NiP 2 . To achieve the same current density , it demands overpotentials of 97 and 107 mV in 1.0 M KOH and phosphate-buffered saline (PBS), respectively. Compared with pure NiP 2 , higher HER electrocatalytic performance for Mn−NiP 2 NSs/CC can be attributed to its lower thermo-neutral hydrogen adsorption free energy , which is supported by density functional theory calculations.
研究领域:
材料科学
·
电化学
·
能量转换
·
纳米材料
·
催化
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·Vol. 48
·期 71
·27557-27567
·
IF 7.2
Xiaobing Xu,Heng Ma,Wei Xu,Xueming Liu,Haifeng Chu,Lei Zhang,Xinglong Wu
Heterostructure and phase engineering are effective method to tune the electronic structure of MoS 2 , which can activate and boost its intrinsic catalytic activity. Herein, the theoretical calculations reveal that the free energy of H∗ adsorption (ΔG H∗ ) for Mo 2 C (−0.65 eV) is lower than MoS 2 (2.05 eV), which is favorable for hydrogen adsorption. Inspired by the theoretical predictions, we develop a facile strategy to prepare nanostructured Mo 2 C/MoS 2 dispersed on reduced graphene oxide (rGO) via a hydrothermal preparation and carburization reaction. Since the Mo 2 C/MoS 2 -rGO nanostructures with great deal of both MoS 2 and Mo 2 C edges by heterostructure and phase engineering, which can induce massive active sites for HER on the surface of rGO, the intimate interfacial coupling effect between Mo 2 C and MoS 2 can effectively improve the charge transfer rate. The Mo 2 C/MoS 2 -rGO catalyst exhibits exceptional HER properties, delivering a high turnover frequency (TOF) of 0.209 s −1 at an overpotential of 200 mV in 0.1 M KOH. This work may open a new window for designing NPM electrocatalysts with highly efficient HER property based on earth-abundant materials.
研究领域:
材料科学
·
电化学
·
纳米技术
·
能量转换
·
催化
✓ 已验证
DOI
高影响因子
Science China-Materials
·
2020
·Vol. 64
·期 5
·1150-1158
·
IF 6.098
Chen Jing,Pan Anqiang,Zhang Wenchao,Cao Xinxin,Lu Rou,Liang Shuquan,Cao Guozhong
Noble metal-free electrocatalysts with high activity are highly desirable for the large-scale application of hydrogen evolution reaction (HER). Mo 2 C-based nanomaterials have been proved as a promising alternative to noble metal-based electrocatalysts owing to the Pt-resembled d-band density and optimal intermediates-adsorption properties. However, the aggregation and excessive growth of crystals often occur during their high-temperature synthesis procedure, leading to low catalytic utilization. In this study, the ultrafine Mo 2 C/Mo 2 N heterostructure with large surface and interface confined in the N-doped carbon nanofibers (N-CNFs) was obtained by a melamine-assisted method. The synergistic effect of Mo 2 C/Mo 2 N heterostructure and plenty active sites exposed on the surface of ultrafine nanocrystals improves the electrocatalytic activity. Meanwhile, the N-CNFs ensure fast charge transfer and high structural stability during reactions. Moreover, the in-situ synthesis method strengthens the interfacial coupling interactions between Mo 2 C/Mo 2 N heterostructure and N-CNFs, further enhancing the electronic conductivity and electrocatalytic activity. Owing to these advantages, Mo 2 C/Mo 2 N@N-CNFs exhibit excellent HER performance with a low overpotential of 75 mV at a current density of 10 mV cm −2 in alkaline solution, superior to the single phased Mo 2 C counterpart and recently reported Mo 2 C/Mo 2 N based catalysts. This study highlights a new effective strategy to design efficient electrocatalysts via integrating heterostructure, nanostructure and carbon modification.
研究领域:
材料科学
·
电化学
·
纳米技术
·
能量转换
·
催化
✓ 已验证
DOI
高影响因子
APPLIED ENERGY
·
2018
·
IF 7.9
Qiongqiong Jiang,Hao Zhang,Ya'nan Deng,Qilan Kang,Hui Hong,Hongguang Jin
Solar-heat driven chemical-looping combustion (S-CLC) is an efficient method for storing solar energy. In the S-CLC process, solar heat is used to drive the endothermic reduction reaction between a hydrocarbon fuel and an oxygen carrier. The solar heat is converted into chemical energy and stored in the reduced oxygen carrier. Owing to their high reactivity at low reaction temperatures, perovskites are treated as promising oxygen carriers in S-CLC. Herein, the reactivity and regenerability of LaCu x Ni 1−x O 3 (x = 0.025, 0.050, 0.075, 0.1, 0.2, 0.3, 0.5) perovskites are studied using methane as the fuel gas. The experimental results show that LaCu 0.1 Ni 0.9 O 3 has the highest reactivity and regenerability among the synthesized materials. At a reduction temperature of 350 °C, more than 46% of the LaCu 0.1 Ni 0.9 O 3 is reduced in 5 min, much higher than the amount of other LaCu x Ni 1−x O 3 perovskites reduced under the same conditions. After 30 redox cycles, the reactivity and micrographs of LaCu x Ni 1−x O 3 are similar to those of fresh material, indicating that LaCu 0.1 Ni 0.9 O 3 has a desirable regenerability. Furthermore, no carbon deposition is observed during the reduction reaction between CH 4 and LaCu x Ni 1−x O 3 . Our study is expected to provide a new method for storing mid-and-low temperature solar heat using this solid perovskite .
研究领域:
材料科学
·
能量存储
·
太阳能转换
·
催化
·
无机化学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Xiangyong Zhang,Ting Guo,Tianying Liu,Kangyan Lv,Zhuangzhi Wu,Dezhi Wang
Tungsten phosphide (WP) has attracted increasing attention in hydrogen evolution reaction (HER) due to its unique catalytic and electronic properties. However, its high preparation temperature often leads to particle excess growth and coarsening. Although tremendous efforts have been made to enlarge the surface areas and reduce particle size, the required high preparation temperature still limits its development. Herein, a facile self-exothermic reduction strategy under an extremely low temperature (300 °C) is proposed to prepare the ultra-fine WP nanoparticles with rich W vacancies. Remarkably, as revealed by XRD , TEM , ICP-OES and XPS analysis, the crystallinity , W vacancies and electron distribution of WP can be well controlled. The W vacancies can activate the neighboring P atoms and the bridge sites as active sites for HER, but also will change the electron distribution , which in turn deteriorates the conductivity of WP. By means of controllable W vacancies, the optimized low crystalline WP catalyst with a moderate number of W vacancies can be obtained, exhibiting a superior HER activity in acidic solution with a small Tafel slope (52 mV dec −1 ), which are smaller than most of WP-based catalysts and among the best records. Furthermore, this work will open a new horizon for both preparation and HER performance improvement of other transition metal phosphides.
研究领域:
材料科学
·
催化
·
能量存储与转换
·
纳米技术
·
电化学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2022
·Vol. 47
·期 87
·37013-37024
·
IF 7.139
Zhixin Chang,Li Guan,Jiajia Zhang,Weiqi Zhang,Qiang Ma,Akeel Shah,Lei Xing,Huaneng Su,Qian Xu
Improving cell performance is the most demanded task in direct methanol fuel cell (DMFC) research, although this fuel cell has several intrinsic features like high energy density , moderate operating temperature and environmentally friendly operation. The catalyst layer (CL) is the site of electrochemical reactions directly affecting the cell performance. Accordingly, the structure and preparation of the CL are crucial in optimizing performance. In this study, a novel gradient catalyst layer (G-CL) for the anode of DMFC is developed and better performance is obtained compared with that of single catalyst layer (S-CL) anode. A G-CL anode is composed of an outer CL of covalent organic framework (COF) materials-mixed catalyst near the microporous layer (MPL) and a conventional inner CL near the membrane side. Different loading of Pt catalyst in the two layers. Therefore, in the G-CL structure, there existed a catalyst concentration gradient and porosity gradient. Anode electrodes are characterized morphologically and electrochemically and the performance of individual cells containing such G-CL designs is measured. The results indicate that incorporation of the appropriate amount of COF materials enables the outer CL not only to have a larger electrochemical surface area (ECSA) and expose more catalytic active sites but also holds a strong proton transfer ability to improve the methanol oxidation reaction (MOR) performance. Due to the presence of the inner layer of the CL formed the methanol gradient oxidation process . With the same platinum-ruthenium (Pt–Ru) catalyst loading, the 5 wt.% COF G-CL anode structure exhibited lower methanol crossover and higher power density (nearly 11% increment) compared with that of the S-CL anode with high methanol concentration (8 M) at 60 °C, showing the promising potential in further applications.
研究领域:
能源材料
·
电化学
·
燃料电池技术
·
纳米材料
·
催化
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2016
·
IF 6.333
Tianrong Zhan,Yumei Zhang,Xiaolin Liu,SiSi Lu,Wanguo Hou
Highly active and low-cost bifunctional electrocatalysts for oxygen evolution and reduction reactions (OER and ORR) hold a heart position for the renewable energy technologies such as metal-air batteries and fuel cells. Here, we reported the synthesis of NiFe layered double hydroxide/reduced graphene oxide (NiFe-LDH/rGO) nanohybrid via the facile solvothermal method followed by chemical reduction. The template role of surfactant and the hybridization of rGO supplied the NiFe-LDH/rGO catalyst with a porous nanostructure and an enhanced conductivity, favoring both mass transport and charge communication of electrocatalytic reactions . The NiFe-LDH/rGO composite not only displayed highly efficient OER activity in alkaline solution with a low onset overpotential of 240 mV, but also only needed an overpotential of 250 mV to reach the 10 mA cm −2 current density . The NiFe-LDH/rGO nanohybrid also offered excellent ORR catalytic activity with onset potential at 0.796 V in alkaline media . The rotating-disk and rotating-ring-disk electrodes both revealed that the ORR on NiFe-LDH/rGO mainly involved a direct four-electron reaction pathways accompanying part of the two-electron process. The excellent bifunctional activity of the NiFe-LDH/rGO nanohybrid could be attributed to the synergistic effects of rGO and NiFe-LDH components due to the strongly coupled interactions.
研究领域:
材料科学
·
电化学
·
能量存储与转换
·
纳米材料
·
催化
✓ 已验证
DOI
高影响因子
Green Energy & Environment
·
2020
·Vol. 6
·期 6
·866-874
·
IF 6.395
Menglei Yuan,Yu Sun,Yong Yang,Jingxian Zhang,Sobia Dipazir,Tongkun Zhao,Shuwei Li,Yongbing Xie,He Zhao,Zhanjun Liu,Guangjin Zhang
Oxygen evolution reaction (OER) as the foremost stumbling block to generate cost-effective clean fuels has received extensive attention in recent years. But, it still maintains the challenge to manipulate the geometric and electronic structure during single reaction process under the same conditions. Herein, we report a simple self-template strategy to generate honeycomb-like Ni 2 P/N,P–C hybrids with preferred electronic architecture. Experiments coupled with theoretical results revealed that the synthesized catalyst has two characteristics: firstly, the unique honeycomb-like morphology not only enables the fully utilization of catalytic active sites but also optimizes the mass/electron transportation pathway, which favor the diffusion of electrolyte to accessible active sites. Secondly, N,P–C substrate, on the one hand, largely contributes the electronic distribution near Fermi level (E F ) thus boosting its electrical conductivity. On the other hand, the support effect result in the upshift of d-band center and electropositivity of Ni sites, which attenuates the energy barrier for the adsorption of OH − and the formation of ∗OOH. In consequence, the optimized Ni 2 P/N,P–C catalysts feature high electrocatalytic activity towards OER (a low overpotential of 252 mV to achieve 10 mA cm −2 ) and 10 h long-term stability, the outstanding performance is comparable to most of transition metal catalysts. This work gives a innovative tactics for contriving original OER electrocatalysts, inspirng deeper understanding of fabricating catalysts by combining theoretical simulation and experiment design.
研究领域:
材料科学
·
电化学
·
能量转换
·
催化
·
纳米材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）