Quantification of Active Site Density and Turnover Frequency: From Single-Atom Metal to Nanoparticle Electrocatalysts.
Quantification of Active Site Density and Turnover Frequency: From Single-Atom Metal to Nanoparticle Electrocatalysts.
复制标题
DOI：
10.1021/jacsau.1c00074
复制
发表时间：
2021-05-24
期刊：
影响因子：
8
通讯作者：
Choi CH
中科院分区：
文献类型：
--
作者：
Bae G;Kim H;Choi H;Jeong P;Kim DH;Kwon HC;Lee KS;Choi M;Oh HS;Jaouen F;Choi CH
单原子催化剂（SAC）具有原子分散的金属阳离子共价嵌入在碳基质中显示出显着的潜力，以实现各种电催化反应的高催化性能。虽然已经取得了相当大的进展，在其合成和电化学应用，进一步的发展和基本的理解是有限的，缺乏的策略，可以允许定量分析其固有的催化特性，即，活性中心密度（SD）和营业额频率（TOF）。在这里，我们展示了一种原位SD定量方法，使用氰化物阴离子作为探针分子。用分光光度法精确测定了Fe-N-C模型催化剂上金属基活性中心不可逆吸附引起的氰化物浓度的降低，并将其与氧还原反应模型反应中电催化活性的相对降低相关联。线性相关性验证了氰化物在Fe-Nx位点上的表面敏感性和金属特异性吸附，基于此可以确定SD和TOF值。值得注意的是，这种分析策略显示出对一系列过渡/贵金属SAC和Pt纳米颗粒在宽pH范围（1-13）内的通用适用性。SD和TOF定量可以提供一个更好的理解的结构-活性关系的广泛的电催化剂，特别是，SACs，没有一般的电化学方法来确定固有的催化特性是可用的。
Single-atom catalysts (SACs) featuring atomically dispersed metal cations covalently embedded in a carbon matrix show significant potential to achieve high catalytic performance in various electrocatalytic reactions. Although considerable advances have been achieved in their syntheses and electrochemical applications, further development and fundamental understanding are limited by a lack of strategies that can allow the quantitative analyses of their intrinsic catalytic characteristics, that is, active site density (SD) and turnover frequency (TOF). Here we show an in situ SD quantification method using a cyanide anion as a probe molecule. The decrease in cyanide concentration triggered by irreversible adsorption on metal-based active sites of a model Fe–N–C catalyst is precisely measured by spectrophotometry, and it is correlated to the relative decrease in electrocatalytic activity in the model reaction of oxygen reduction reaction. The linear correlation verifies the surface-sensitive and metal-specific adsorption of cyanide on Fe–Nx sites, based on which the values of SD and TOF can be determined. Notably, this analytical strategy shows versatile applicability to a series of transition/noble metal SACs and Pt nanoparticles in a broad pH range (1–13). The SD and TOF quantification can afford an improved understanding of the structure–activity relationship for a broad range of electrocatalysts, in particular, the SACs, for which no general electrochemical method to determine the intrinsic catalytic characteristics is available.
登录
查看更多内容
原子分散的镍-氮-硫物质锚定在多孔碳纳米片上，可有效氧化水
影响因子：
16.6
作者：
Hou, Yang;Qiu, Ming;Feng, Xinliang
通讯作者：
Feng, Xinliang
影响因子：
56.9
作者：
Gu, Jun;Hsu, Chia-Shuo;Hu, Xile
通讯作者：
Hu, Xile
影响因子：
9.2
作者：
Brightman, E.;Hinds, G.;O'Malley, R.
通讯作者：
O'Malley, R.
影响因子：
16.6
作者：
Ju W;Bagger A;Hao GP;Varela AS;Sinev I;Bon V;Roldan Cuenya B;Kaskel S;Rossmeisl J;Strasser P
通讯作者：
Strasser P
影响因子：
32.5
作者：
Choi, Chang Hyuck;Lim, Hyung-Kyu;Jaouen, Frederic
通讯作者：
Jaouen, Frederic