解读电化学氨基合成的桥梁氧气空缺诱导的级联电荷效应
Ashmita Biswas1, Narad Barman2, Avinash Nambron1
1Institute of Nano Science and Technology, Sector-81, Mohali-140306, Punjab, India. rsdey@inst.ac.in.
Materials horizons
|February 28, 2024
概括
在SnO2中,氧空位工程通过改变电子结构和创建活性位点来增强降解反应 (NRR). 这项研究在工程 SnO2 材料上实现了高48.5%的 NRR 法拉代克效率.
科学领域:
- 材料科学 材料科学 材料科学
- 电化学 电化学 电化学
- 催化剂是一种催化剂.
背景情况:
- 半导体材料在电催化过程中通常表现不佳,特别是对于降解反应 (NRR),由于电荷缺陷和大带间隙.
- 氧空位工程是增强半导体电催化活性的一个有希望的策略.
- 对不同类型的空位如何影响NRR的材料结构和费用分配缺乏详细的了解.
研究的目的:
- 为了合成氧气空缺工程的SnO2与控制的结构转换从平面内 (iov) 到桥式氧气空缺 (bov).
- 调查氧气空缺在改变SnO2.2电子结构和N2吸附性质中的作用.
- 阐明工程活性位点对降解反应的动力学和效率的影响.
主要方法:
- SnO2的合成与氧气空缺的逐渐结构转变.
- 电子结构变化的表征,包括价值带转移和混合轨道占用.
- 在现场减弱总反射红外 (ATR-IR) 光谱检测以识别反应中间体.
- 对降解反应 (NRR) 和演化反应 (HER) 的电催化试验.
主要成果:
- 在SnO2中,氧空位工程导致了向费米水平向上移动的价值带最大值,影响了N2吸附和N-N键极化.
- 邻近桥式氧空隙 (bov) 的sn原子表现出悬浮的电荷,在较低的超电位时促进了NRR.
- 设计的SnO2实现了NRR的48.5%的高法拉代效率,在O原子上优先结合Sn位点,抑制HER.
- 使用现场ATR-IR研究确定了稳定的反应中间体.
结论:
- 氧气空缺显著改变了SnO2的晶体和电子结构,为NRR创造了有效的活性位点.
- 氧气空缺的类型和密度在确定中间体的结合强度和整体NRR率方面发挥着至关重要的作用.
- 与之前报告的基于 SnO2 的催化剂相比,工程 SnO2 对 NRR 显示出更高的性能.
相关概念视频
03:24Common Ion Effect
41.7K
Compared with pure water, the solubility of an ionic compound is less in aqueous solutions containing a common ion (one also produced by dissolution of the ionic compound). This is an example of a phenomenon known as the common ion effect, which is a consequence of the law of mass action that may be explained using Le Châtelier’s principle. Consider the dissolution of silver iodide:
41.7K
03:00Electrolysis
26.4K
In a galvanic cell, the electrical work is done by a redox system on its surroundings as electrons produced by the spontaneous redox reactions are transferred through an external circuit. Alternatively, an external circuit does work on a redox system by imposing a voltage sufficient to drive an otherwise nonspontaneous reaction in a process known as electrolysis. For instance, recharging a battery involves the use of an external power source to drive the spontaneous (discharge) cell reaction in...
26.4K
03:25Free Energy Changes for Nonstandard States
11.4K
The free energy change for a process taking place with reactants and products present under nonstandard conditions (pressures other than 1 bar; concentrations other than 1 M) is related to the standard free energy change according to this equation:
where R is the gas constant (8.314 J/K·mol), T is the absolute temperature in kelvin, and Q is the reaction quotient. This equation may be used to predict the spontaneity of a process under any given set of conditions.
Reaction Quotient...
where R is the gas constant (8.314 J/K·mol), T is the absolute temperature in kelvin, and Q is the reaction quotient. This equation may be used to predict the spontaneity of a process under any given set of conditions.
Reaction Quotient...
11.4K
02:16Lewis Acids and Bases
14.1K
This lesson delves into Lewis acids and bases in the context of the octet rule for electron-deficient compounds. Here, the concept is discussed, emphasizing the group 13 elements like boron or aluminium. Since group 13 elements possess three valence electrons, they form trivalent compounds with a sextet of electrons and a vacant orbital for the central atom. Consequently, these electron-deficient compounds accept electrons from other species to complete their octet in a chemical reaction. They...
14.1K
02:16Brønsted-Lowry Acids and Bases
19.4K
In 1923, the Brønsted–Lowry definition of acids and bases was proposed by Johannes Brønsted and Thomas Lowry. According to this theory, a Brønsted acid is defined as a species that donates a proton in a chemical reaction and gets converted to its conjugate base. A Brønsted base is defined as a species that accepts a proton in a chemical reaction and gets converted into its conjugate acid. These transfers of protons are caused by the displacement of electrons in these reactions, which is...
19.4K
01:20Titration of a Weak Base with a Strong Acid
5.1K
The titration curve of a weak base like ammonia with a strong acid like hydrochloric acid is the mirror image of the titration curve of a weak acid with a strong base.
Using the ICE table and substituting the Kb value, we calculate the initial pH of 50 mL of 0.1 M ammonia to be 11.11. Addition of 25 mL of 0.1 M hydrochloric acid to this solution of ammonia results in a buffer with an equal concentration of ammonia and ammonium ions. The pH of this buffer can be calculated by substituting these...
Using the ICE table and substituting the Kb value, we calculate the initial pH of 50 mL of 0.1 M ammonia to be 11.11. Addition of 25 mL of 0.1 M hydrochloric acid to this solution of ammonia results in a buffer with an equal concentration of ammonia and ammonium ions. The pH of this buffer can be calculated by substituting these...
5.1K