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Monojit Das Bairagya Ryan J. Bujol Prof. Noémie Elgrishi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(18):3991-4000
Development of highly active molecular electrocatalysts for fuel-forming reactions has relied heavily on understanding mechanistic aspects of the electrochemical transformations. Careful fine-tuning of the ligand environment oriented mechanistic pathways towards higher activity and optimal product distribution for several catalysts. Unfortunately, many catalysts deactivate in bulk electrolysis conditions, diminishing the impact of the plethora of highly tuned molecular electrocatalytic systems. This Minireview covers classical and emerging methods developed to circumvent catalyst deactivation and degradation, with an emphasis on successes with molecular electrocatalysts. 相似文献
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Xinghui Liu Lirong Zheng Chenxu Han Hongxiang Zong Guang Yang Shiru Lin Ashwani Kumar Amol R. Jadhav Ngoc Quang Tran Yosep Hwang Jinsun Lee Suresh Vasimalla Zhongfang Chen Seong-Gon Kim Hyoyoung Lee 《Advanced functional materials》2021,31(18):2100547
Single-atom catalysts (SACs) have become the forefront of energy conversion studies, but unfortunately, the origin of their activity and the interpretation of the synchrotron spectrograms of these materials remain ambiguous. Here, systematic density functional theory computations reveal that the edge sites—zigzag and armchair—are responsible for the activity of the graphene-based Co (cobalt) SACs toward hydrogen evolution reaction (HER). Then, edge-rich (E)-Co single atoms (SAs) were rationally synthesized guided by theoretical results. Supervised learning techniques are applied to interpret the measured synchrotron spectrum of E-Co SAs. The obtained local environments of Co SAs, 65.49% of Co-4N-plane, 13.64% in Co-2N-armchair, and 20.86% in Co-2N-zigzag, are consistent with Athena fitting. Remarkably, E-Co SAs show even better HER electrocatalytic performance than commercial Pt/C at high current density. Using the joint effort of theoretical modeling, thorough characterization of the catalysts aided by supervised learning, and catalytic performance evaluations, this study not only uncovers the activity origin of Co SACs for HER but also lays the cornerstone for the rational design and structural analysis of nanocatalysts. 相似文献
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Xiang-Da Zhang Shu-Zhen Hou Jian-Xiang Wu Prof. Dr. Zhi-Yuan Gu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(7):1604-1611
The electrochemical reduction of CO2 presents a promising strategy to mitigate the greenhouse effect and reduce excess carbon dioxide emission to realize a carbon-neutral energy cycle, but it suffers from the lack of high-performance electrocatalysts. In this work, catalytic active cobalt porphyrin [TCPP(Co)=(5,10,15,20)-tetrakis(4-carboxyphenyl)porphyrin-CoII] was precisely anchored onto water-stable 2D metal–organic framework (MOF) nanosheets (Zr-BTB) to obtain ultrathin 2D MOF nanosheets [TCPP(Co)/Zr-BTB] with accessible catalytic sites for the CO2 reduction reaction. Compared with molecular cobalt porphyrin, the TCPP(Co)/Zr-BTB exhibits an ultrahigh turnover frequency (TOF=4768 h−1 at −0.919 V vs. reversible hydrogen electrode, RHE) owing to high active-site utilization. In addition, three post-modified 2D MOF nanosheets [TCPP(Co)/Zr-BTB-PABA, TCPP(Co)/Zr-BTB-PSBA, TCPP(Co)/Zr-BTB-PSABA] were obtained, with the modifiers of p-(aminomethyl)benzoic acid (PABA), p-sulfobenzoic acid potassium (PSBA), and p-sulfamidobenzoic acid (PSABA), to change the micro-environments around TCPP(Co) through the tuning of steric effects. Among them, the TCPP(Co)/Zr-BTB-PSABA exhibited the best performance with a faradaic efficiency (FECO) of 85.1 %, TOF of 5315 h−1, and jtotal of 6 mA cm−2 at −0.769 V (vs. RHE). In addition, the long-term durability of the electrocatalysts is evaluated and the role of pH buffer is revealed. 相似文献
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CO2 electrocatalysis as a hydrocarbon is a promising means of achieving economical CO2-mediated hydrogen energy cycling. Hydrocarbons are renewable hydrogen storage materials. The development of reliable metal alloy electrocatalysts is an urgent but challenging task associated with such systems, although there is still a lack of precise reaction mechanism design. In this study, the performance of Pd10Ag5 alloy nanoparticles (NPs) and Pd10Sn5 alloy nanoparticles (NPs) on the electrocatalytic reaction of CO2 was compare. The kinetic and density functional theory (DFT) calculations show that the selectivity of the Pd-based bimetallic catalyst to the C2 product is greater than that of C1, and the stability of Pd10Ag5 is better and less affected by the reaction environment. However, the catalytic performance of the Pd10Sn5 electrocatalyst in the liquid phase is the best. The insight obtained from the calculations is used to develop criteria for identifying new and improved catalysts for electrochemical CO2 reduction. 相似文献
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Starting from [M3(CO)12] (M = Fe or Ru) and [CH3CCo3(CO)9], the electron-tranfer-chain catalyzed synthesis of new Fe, Ru, and Co carbonyl clusters in which one or several carbonyl ligands have been selectively substituted by one or several ferrocenyldiphenylphosphine (FDPP) ligands has been achieved using the electron-reservoir complexes [Fe(I)Cp(arene)] as electrocatalysts. The number of FDPP ligands selectively introduced can be chosen from one per cluster for the three clusters up to one per metal for the Ru and Co clusters. The advantage of this family of electrocatalysts is that the driving force for the initiation step can be varied by changing the number of methyl groups on the rings. The FDPP substituted clusters show one reversible wave by cyclic voltammetry. 相似文献
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保证催化剂质量活性(通常以贵金属质量为计量)的基础上,减小催化剂中助催化剂的用量可有效降低燃料电池膜电极组(MEA)催化剂层的厚度,从而提高贵金属利用率和增大放电电压.于此,本文以微量NaH2PO2作为还原剂,适当调节合成溶液的碱度,成功制备了助催化剂Ni和P的掺杂量分别低至0.2%(w)和0.05%(w)的三元碳载Pd-Ni-P纳米合金催化剂.所得催化剂在0.5 mol/L CH3CH2OH+1 mol/L NaOH溶液中的循环伏安表征显示,质量活性最高可达到2466 mA•mg-1 Pd,是商业化Pd/C催化剂的2.7倍;同时,计时电流法测试表明,该催化剂的稳定性相对于商业化催化剂提升了2.8倍.这说明所得低掺杂型Pd-Ni-P催化剂达到了上述设计要求.本工作可能为燃料电池高效低成本阳极催化剂设计制备提供新的思路. 相似文献
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Inside Cover: Exploring the Performance Improvement of the Oxygen Evolution Reaction in a Stable Bimetal–Organic Framework System (Angew. Chem. Int. Ed. 31/2018) 下载免费PDF全文
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Dawei Chen Man Qiao Ying‐Rui Lu Li Hao Dongdong Liu Prof. Chung‐Li Dong Prof. Yafei Li Prof. Shuangyin Wang 《Angewandte Chemie (International ed. in English)》2018,57(28):8691-8696
The oxygen evolution reaction (OER) is an ideal model to study the relationship between the activity and the surface properties of catalysts. Defect engineering has been extensively developed to tune the electrocatalytic activity for OER. Compared to the anion vacancies in metal oxides, cation vacancies are more challenging to selectively generate, and the insight into the structure and activity of cation vacancies‐rich catalysts are lacked. Herein, using SnCoFe perovskite hydroxide as a precursor, abundant Sn vacancies on the surface were preferentially produced by Ar plasma. Sn vacancies could be preferentially produced as confirmed by the X‐ray absorption spectra, probably owing to the lower lattice energy and weaker chemical bonds of Sn(OH)4. The Sn vacancies promoted the exposure of active CoFe sites, resulting in an amorphous surface layer, modulated the conductivity, and thus enhanced the OER performance. 相似文献