| 查看: 962 | 回复: 1 | |||
susanf金虫 (小有名气)
|
[交流]
华东师大课题组在电催化析氢反应微观机制和反应动力学方面的重要研究进展 已有1人参与
|
|
华东师范大学张坤研究员课题组在电催化析氢反应取得重要研究进展，论文发表在jacs au杂志上： 论文链接：https://pubs.acs.org/doi/10.1021/jacsau.2c00187 题目：activation of h2o tailored by interfacial electronic states at a nanoscale interface for enhanced electrocatalytic hydrogen evolution 摘要 despite the fundamental and practical significance of the hydrogen evolution reaction (her), the reaction kinetics at the molecular level are not well-understood, especially in basic media. here, with zif-67-derived co-based carbon frameworks (co/ncs) as model catalysts, we systematically investigated the effects of different reaction parameters on the her kinetics and discovered that the her activity was directly dependent not on the type of nitrogen in the carbon framework but on the relative content of surface hydroxyl and water (oh╟/h2o) adsorbed on co active sites embedded in carbon frameworks. when the ratio of the oh╟/h2o was close to 1:1, the co/nc nanocatalyst showed the best reaction performance under the condition of high-ph electrolytes, e.g., an overpotential of only 232 mv at a current density of 10 ma cm╟2 in the 1 m koh electrolyte. we unambiguously identified that the structural water molecules (sws) in the form of hydrous hydroxyl complexes absorbed on metal centers {ohad·h2o@m+} were catalytic active sites for the enhanced her, where m+ could be transition or alkaline metal cations. different from the traditional hydrogen bonding of water, the hydroxyl (hydroxide) groups and water molecules in the sws were mainly bonded together via the spatial interaction between the p orbitals of o atoms, exhibiting features of a delocalized π-bond with a metastable state. these newly formed surface bonds or transitory states could be new weak interactions that synergistically promote both interfacial electron transfer and the activation of water (dissociation of o╟h bonds) at the electrode surface, i.e., the formation of activated h adducts (h*). the capture of new surface states not only explains ph-, cation-, and transition-metal-dependent hydrogen evolution kinetics but also provides completely new insights into the understanding of other electrocatalytic reductions involving other small molecules, including co2, co, and n2. 研究内容：迄今为止，还没有统一的模型来解释电催化析氢的微观动力学，例如ph、碱金属离子和过渡金属依赖的反应动力学。使用zif-67衍生的纳米结构碳作为原型电催化剂，作者首先提供了确凿的证据并证实界面sws以含水羟基络合物的形式吸附在金属{ohad·h2o@m+}（m+是过渡金属或碱金属阳离子）是水活化（或离解）和随后质子还原的活性位点。sws中两个o原子的空间相互作用可能是一种新型的弱相互作用，其强度介于氢键和化学共价键之间。此外，由于sws中两个o原子的p轨道的空间重叠，形成了一个表面瞬态系综（方案1c╟e），该系综协同促进了水和界面电子的激活以及纳米尺度界面上的质子转移。应该强调的是，这些动态表面中间态（pbi）并不稳定，这解释了her（甚至oer和氧还原反应）对微环境的极端敏感性，例如ph和阳离子依赖性效应。sw主导的表面瞬态概念可调节her的微观动力学，从而优化整个电化学界面，从而提高活性，而不是仅优化催化剂结构，这对于设计更活跃的电化学界面以进行涉及小分子（co2、co、n2、o2和h2）的储能和转化反应至关重要。 作者强调了作为析氢催化活性中心的结构水（sws）的概念与氢键水的概念完全不同，因为sws是两个相邻的水分子，主要通过两个o原子的p轨道的空间重叠来结合，形成具有π键特征的局部化学键，由于空间轨道重叠，这为通过表面离域进行电子转移提供了一个替代通道。sws作为协同电子和质子转移的替代通道，同时作为活化水o╟h键的活性位点，这一概念不仅可以为水环境中纳米材料催化反应的催化剂或电解质的设计和选择提供重要指导，包括co2或co还原、氮还原和其他电催化还原反应。 全文pdf免费链接如下：https://pubs.acs.org/doi/pdf/10.1021/jacsau.2c00187 |
回复此楼» 猜你喜欢
304求调剂
已经有3人回复
-
国家级人才课题组招收2026年入学博士
已经有1人回复
-
物理化学论文润色/翻译怎么收费?
已经有78人回复
-
304求调剂
已经有4人回复
-
求调剂：报考中矿0817 总分299 有竞赛、科研经历
已经有1人回复
-
0817一志愿苏州大学280复试调剂
已经有4人回复
-
0817找调剂
已经有6人回复
-
PDF在线压缩软件
已经有3人回复
-
材料/化学相关专业2026级学术/专业型硕士研究生
已经有11人回复
» 本主题相关商家推荐: (我也要在这里推广)
 |
2楼2022-06-27 07:55:14
100