INORGANIC CHEMISTRY
·
2023
·
IF 4.6
Yu-Qing Yang,Shen-Jing Ji,Nian-Tzu Suen
Reported are the synthesis, material characterization, and electrocatalytic hydrogen evolution reaction (HER) in acid and alkaline electrolytes for the Brewer intermetallic phase, Nb6Co7 and Mo6Co7. It was realized that the overpotential at a current density of 10 mA/cm2 (η10) for Nb6Co7 (η10 = 62 mV) and Mo6Co7 (η10 = 143 mV) are both much lower than that of using a single Co metal (η10 = 253 mV) in alkaline electrolytes. The enhancement of electrocatalytic HER activity of Nb6Co7 and Mo6Co7 can be attributed to the hypo-hyper-d-electronic interaction between Nb/Mo and Co elements. Based on the result of density functional theory calculation, alloying between Nb/Mo and Co elements will increase the antibonding state population of the Co–Co bond near the Fermi level (EF), which induces the synergistic effect to influence the adsorption energy of the H atom (ΔGH) on the surface of Nb6Co7 and Mo6Co7. Moreover, the role of the Nb element is not only a simple electron donor but is also an anchor position for the OH molecule (i.e., dual function) due to the bonding character of the Nb–Co bond near EF. It can reduce the OH position effect as well as the activation energy for water dissociation, which rationalizes the high and robust HER performance of Nb6Co7 to that of commercial Pt/C (η10 = 67 mV) in alkaline electrolytes.
研究领域:
材料科学
·
电化学
·
理论计算
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Yanqin Xue,Qing Yan,Xiaojing Bai,Yanyan Xu,Xuan Zhang,Yiju Li,Kai Zhu,Ke Ye,Jun Yan,Dianxue Cao,Guiling Wang
The development of efficient bifunctional catalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is essential for reducing the cost of hydrogen production by water splitting. Herein, hollow microtubes composed of RuNi 1 Co 1 alloy nanoparticles uniformly embedded in the carbon matrix (RuNi 1 Co 1 @CMT) are prepared through a simple impregnation followed by reduction. Benefiting from the unique mosaic structure and the synergistic effect between Ru and NiCo, RuNi 1 Co 1 @CMT achieves more exposed active sites and improved reaction kinetics. As a consequence, RuNi 1 Co 1 @CMT exhibits considerable catalytic activities with the overpotentials of 78 mV for HER and 299 mV for OER at 10 mA cm −2 in 1 M KOH. In addition, RuNi 1 Co 1 @CMT exhibits excellent stability for up to 30 h in both HER and OER processes at 20 mA cm −2 , which is attributed to the protection of the RuNi 1 Co 1 alloy particles by the carbon layer. Furthermore, the assembled RuNi 1 Co 1 @CMT || RuNi 1 Co 1 @CMT overall water splitting system shows a cell voltage of 1.58 V at 10 mA cm −2 . The density functional theory (DFT) calculations indicate that the addition of Ru can optimize the hydrogen adsorption free energy of Ni and Co sites. Finally, a solar panel-driven water splitting device is built, which can realize green and sustainable hydrogen production. The fabrication of RuNi 1 Co 1 @CMT provides a new way for the preparation of effective alloy nanomaterials for energy storage and conversion.
研究领域:
材料科学
·
催化化学
·
能源转换
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2017
·Vol. 5
·期 21
·10669-10677
·
IF 8.867
Lian-Kui Wu,Wei-Yao Wu,Jie Xia,Hua-Zhen Cao,Guang-Ya Hou,Yi-Ping Tang,Guo-Qu Zheng
A nanostructured nickel–cobalt alloy with an oxide layer was fabricated and its superior catalytic activity towards the electrochemical oxygen evolution reaction in alkaline media was investigated. Firstly, a NiCo–SiO2 composite film was prepared via a potentiostatic electro-codeposition method. Then the SiO2 template was etched and the NiCo component was activated leading to the generation of a NiCoOx layer during consecutive CV scans in concentrated alkaline solution. The results show that this nanostructured NiCo alloy with the oxide layer can provide a current density of 100 mA cm−2 in 1.0 M KOH at a low overpotential of 326 mV and exhibits good stability towards water oxidation. The excellent OER performance is enabled with the unique metal-oxide structure, which allows high electrical conductivity in the metal and high catalytic activity on the oxide.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY
·
2022
·
IF 2.004
C. Zhang,Y. Wan,X.H. Liang,M.H. Rong,G.T. Ma,L. Li,C.H. Hu,Chengying Tang
Au–Co nanoparticles (NPs) were prepared by water-phase chemical reduction method with metal precursor. The samples were coated with silica by Stöber method and characterized by ultraviolet and visible spectrophotometer (UV–vis), transmission electron microscopy (TEM) to obtain the absorption spectrum , size, composition distribution of the nanoparticles. The melting behaviors of the prepared Au 8 Co 2 NPs and Au 6 Co 4 NPs were examined by differential scanning calorimetry (DSC). It was observed by DSC measurements that two endothermic effects existed in range of 700.0 K–1350.0 K, corresponding to the melting temperatures of the nanoparticles and the bulk Au–Co alloys, respectively. The surface tension, surface segregation and surface energy of Au–Co NPs of particle size and temperature were calculated by the Butler's equation. On the basis of the obtained experimental results and the Gibbs free energy contributed by surface effects of pure elements and alloys at nanoscale, the nanophase diagrams of Au–Co system with various sizes were optimized. It was indicated that the calculated nanophase diagrams were in good agreement with the experimental results. The calculated eutectic temperatures decreased with the decrease of the size.
研究领域:
材料科学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Minerals Metallurgy and Materials
·
2018
·Vol. 25
·期 9
·1027-1034
·
IF 1.261
Wang Le-ping,Chen Gang,Shen Qi-xin,Li Guo-min,Guan Shi-you,Li Bing
SnCo alloy nanowires were successfully electrodeposited from SnCl 2 −CoCl 2 −1-ethyl-3-methylimidazolium chloride (EMIC) ionic liquid without a template. The nanowires were obtained from the molar ratio of 5:40:60 for SnCl 2 :CoCl 2 :EMIC at −0.55 V and showed a minimum diameter of about 50 nm and lengths of over 20 μm. The as-fabricated SnCo nanowires were about 70 nm in diameter and featured a Sn/Co weight ratio of 3.85:1, when used as an anode for a Li-ion battery, they presented respective specific capacities of 687 and 678 mAh·g −1 after the first charge and discharge cycle and maintained capacities of about 654 mAh·g−1 after 60 cycles and 539 mAh·g −1 after 80 cycles at a current density of 300 mA·g −1 . Both the nanowire structure and presence of elemental Co helped buffer large volume changes in the Sn anode during charging and discharging to a certain extent, thereby improving the cycling performance of the Sn anode.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2024
·Vol. 48
·期 27
·12166-12173
·
IF 2.7
Yali Chen,Cuijiao Zhao,Shuyu Wang,Li Zhang,Guoqiang Liu,Weiji Dai,Yudong Zhang,Can Cui,Saifang Huang
Exploring efficient non-noble metal catalysts for the hydrogen evolution reaction (HER) will contribute to the development of clean and green energy technologies. Herein, we adopted a “waste utilization” strategy by using readily available and inexpensive coconut shell waste as a carbon source to synthesize carbon materials anchored with a Cu7Co alloy (Cu7Co/C) as a potential electrocatalyst for the hydrogen evolution reaction (HER). Utilizing a combination of hydrothermal and pyrolysis methods, the synthesized Cu7Co/C catalyst showcases superior HER electrocatalytic performance in alkaline solutions, with an overpotential of 134 mV at 10 mA cm−2 and a Tafel slope of 94 mV dec−1. The alloying of Cu and Co within Cu7Co/C markedly improves charge transfer capabilities, enhancing HER electrocatalysis. This research underscores the exceptional catalytic performance and stability of Cu7Co/C nanocomposites in alkaline media for the HER, attributed to a synergistic effect between the carbon derived from coconut shells and the bimetallic Cu7Co alloy.
研究领域:
材料科学
·
可再生能源
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2024
·
IF 3.3
Zhi-Qiang Wang,Wanjun Guo,Shengchao Jia,Yaxuan Jing,Shiting Li,Yong Guo,Xiaohui Liu,Xue-Qing Gong,Yanqin Wang
The selective production of primary amines through reductive amination has received increasing attention due to their extensive applications, while efficient reductive amination is still challenging. Herein, a novel strategy was developed to realize the efficient reductive amination of carbonyl compounds with NH3 via d–d orbital coupling strategies in RuCo alloys. The designed series of RuCo alloy catalysts not only exhibited excellent performance in conversion of various substrates but also demonstrated universal applicability across different supports. The key role of RuCo alloy is its unique ability to effectively catalyze the ammonolysis of a Schiff base, the rate-determining step in reductive amination. Theoretical studies reveal that the d–d orbital coupling strategies break the five d orbital equivalent contributions of metal (Co or Ru) atoms, and the d orbitals primarily contribute through the dz2 and dx2-y2 orbitals of Ru and the dz2 orbital of Co on the RuCo(001) surface, which significantly driving the homolytic NH3 dissociation during the ammonolysis of the Schiff base. Furthermore, stable Co–H covalent bond species and RuCo-NH2 half-ionic and half-covalent bond species on the RuCo(001) surface were generated with lower energy levels. This work not only achieves efficient reductive amination but also provides an atomic orbital-level understanding of the d–d orbital coupling strategies for heterogeneous catalysis.
研究领域:
催化化学
·
材料科学
·
理论化学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2017
·Vol. 41
·期 10
·4031-4039
·
IF 3.269
Xiaofei Song,Jianmin Hao,Yijia Bai,Limin Han,Guangfei Yan,Xu Lian,Jiansheng Liu
Al–Cu–Co alloys containing different intermetallic compound phases were fabricated by the arc-melting method and used as heterogeneous catalysts for solvent-free cyclohexane oxidation by oxygen. The element composition and bulk structure were characterized by ICP-OES, XRD, SEM, TEM and XPS. Co species were the major active component and a small amount of Cu dissolved in the Al13Co4 phase of the alloy exhibited a synergetic effect on improving the catalytic activity. Cu dissolved in the Al13Co4 phase, a decagonal quasicrystal approximant with a special atomic arrangement structure, could increase the electrical conductivity and accelerate electron transfer during the catalytic oxidation of cyclohexane, and thus improved the catalytic activity of the alloy. Among all the alloys prepared in the present work, the Al60Cu5Co35 alloy exhibited the best catalytic performance with a cyclohexane conversion of 6.4% and a total selectivity of 95.2% to cyclohexanol and cyclohexanone. No significant change in the catalytic activity of the Al60Cu5Co35 alloy was observed after five cycles.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Xing Ji,Zhenzhen Wang,Zefeng Fang,Zhongzhe Wei,Jing Wang
Understanding the interaction between Ru and Co components and the alloy ratio effects on the catalytic process is a technical challenge that requires a precise alloy structural design. This study proposes an effective stepwise annealing method for the construction of RuCo alloy-based electrocatalysts with varied Ru:Co ratios. Interestingly, as the concentration of Co in the first-step pyrolysis products increases, the secondary pyrolysis results in RuCo composites undergoing a transition from incomplete alloying to alloy ratios of 1:1, 1:2, and 1:8. When the alloy ratio is 1:1, more Run+ and Co0 transform into Ru0 and Co2/3+. In 1 M KOH, RuCo-0.6/NC demonstrates outstanding catalytic performance and durability even superior to that of commercial Pt/C, delivering a lower overpotential of 16 mV at 10 mA cm–2. DFT calculations reveal that the fast H2O dissociation and moderate H adsorption guarantee the superior activity of RuCo.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2018
·
IF 5.091
Guoqing Sheng,Jiahui Chen,Huangqing Ye,Zhixiong Hu,Xian-Zhu Fu,Rong Sun,Weixin Huang,Ching-Ping Wong
Monodisperse hollow mesoporous PdCo alloy nanospheres are prepared via a simple galvanic replacement reaction. The as-prepared PdCo hollow nanospheres have small diameter, such as Pd 78 Co 22 nanospheres of diameter about 25 nm and mesoporous shells about 4–5 nm. The Pd 78 Co 22 hollow mesoporous nanospheres possess the largest electrochemical active surface areas (ECSA, 53.91 m 2 g −1 ), mass activity (1488 mA mg −1 ) and specific activity (2.76 mA cm −2 ) towards to methanol oxidation relative to the Pd 68 Co 32 , Pd 92 Co 8 hollow mesoporous nanospheres and commercial Pd/C catalysts. Moreover, the activity of Pd 78 Co 22 after long-term stability tests is still the best and even better than those of fresh Pd 68 Co 32 and commercial Pd/C catalysts. The PdCo catalysts not only effectively reduce the Pd usage by forming hollow structure, but also fully realize the Pd-Co alloying effects for enhancing the methanol oxidation catalytic performance.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2017
·Vol. 164
·期 13
·E422
·
IF 3.259
Kaiyuan Zheng,Xinhua Cheng,Yanpeng Dou,Hua Zhu,Dihua Wang
Nickel-cobalt (Ni–Co) alloy was prepared by electrochemical reduction of solid NiO and Co3O4 powder in molten Na2CO3-K2CO3 melt at 750°C. Cyclic voltammetry (CV) and potentiostatic electrolysis experiments indicate that the electroreduction experiences an initial rapid reduction of Co3O4 to CoO, followed by a further co-reduction of NiO and CoO to Ni-Co alloy. The metallic Ni-Co powder was obtained either by potentiostatic electrolysis at potential more negative than −1.25 V (vs. Ag/Ag2SO4) or by constant cell voltage electrolysis at above 1.7 V. An oxide-layer-covered Ni11Fe10Cu alloy rod serving as an inert anode for oxygen evolution behaved stably and reliably for long-term operation. Ni and Co distributed uniformly in the product. The morphology and crystal phase of the alloy was significantly influenced by the electrolysis time. Furthermore, the obtained Ni-Co powders were typical ferromagnetic alloy with relatively high saturation magnetization.
研究领域:
冶金学
·
电化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ChemSusChem
·
2019
·Vol. 13
·期 5
·964-973
·
IF 7.804
Ronghui Que,Maolin Li,Hong Yao,Xiuhua Wang,Fan Liao,Mingwang Shao
Graphical Just add water : A mere trace of water roughly halves the size and regulates the composition of polyhedral Ni x Co 1− x alloy nanoparticles prepared by the polyol method. The Ni 0.6 Co 0.4 nanoparticle alloy obtained by adding 70 μL of water shows superior electrocatalytic performance in the methanol oxidation reaction owing to its appropriate Ni/Co ratio and is a promising electrocatalyst for use in direct methanol fuel cells. Highly active Ni-based catalysts have attracted much attention but are still facing challenges owing to the immature synthetic method. Herein, polyhedral Ni x Co 1− x alloy was prepared by a facile modified polyol method in which a trace amount of water could halve the particle size of the alloy. The Ni/Co ratios in Ni x Co 1− x alloy strictly depended on the used amount of water owing to the different solubilities of the precursors. Among them, the Ni 0.6 Co 0.4 nanoparticles obtained with 70 μL of deionized water exhibited the best performance in the methanol oxidation reaction with a peak current density of 116 mA cm −2 in the presence of 1 m NaOH+0.5 m CH 3 OH solution, which is higher than those of Ni 0.7 Co 0.3 (80 mA cm −2 ) and Ni 0.5 Co 0.5 (33 mA cm −2 ). The excellent performance of Ni 0.6 Co 0.4 is attributed to the unique structure with appropriate Ni/Co ratio, which elongates the C−O bond in methanol and lowers the reaction free energy according to DFT calculations.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）