当前位置：
X-MOL 学术
›
ACS Catal.
›
论文详情
Our official English website, www.x-mol.net, welcomes your
feedback! (Note: you will need to create a separate account there.)
The Role of Composition of Uniform and Highly Dispersed Cobalt Vanadium Iron Spinel Nanocrystals for Oxygen Electrocatalysis
ACS Catalysis ( IF 11.3 ) Pub Date : 2018-01-18 00:00:00 , DOI: 10.1021/acscatal.7b03529 Kalapu Chakrapani 1 , Georg Bendt 1 , Hamidreza Hajiyani 2 , Thomas Lunkenbein 3 , Mark T. Greiner 4 , Liudmyla Masliuk 3 , Soma Salamon 2 , Joachim Landers 2 , Robert Schlögl 3, 4 , Heiko Wende 2 , Rossitza Pentcheva 2 , Stephan Schulz 1 , Malte Behrens 1, 5
ACS Catalysis ( IF 11.3 ) Pub Date : 2018-01-18 00:00:00 , DOI: 10.1021/acscatal.7b03529 Kalapu Chakrapani 1 , Georg Bendt 1 , Hamidreza Hajiyani 2 , Thomas Lunkenbein 3 , Mark T. Greiner 4 , Liudmyla Masliuk 3 , Soma Salamon 2 , Joachim Landers 2 , Robert Schlögl 3, 4 , Heiko Wende 2 , Rossitza Pentcheva 2 , Stephan Schulz 1 , Malte Behrens 1, 5
Affiliation
|
Cation substitution in transition-metal oxides is an important approach to improve electrocatalysts by the optimization of their composition. Herein, we report on phase-pure spinel-type CoV2–xFexO4 nanoparticles with 0 ≤ x ≤ 2 as a new class of bifunctional catalysts for the oxygen evolution (OER) and oxygen reduction reactions (ORR). The mixed-metal oxide catalysts exhibit high catalytic activity for both OER and ORR that strongly depends on the V and Fe content. CoV2O4 is known to exhibit a high conductivity, while in CoFe2O4 the cobalt cation distribution is expected to change due to the inversion of the spinel structure. The optimized catalyst, CoV1.5Fe0.5O4, shows an overpotential for the OER of ∼300 mV for 10 mA cm–2 with a Tafel slope of 38 mV dec–1 in alkaline electrolyte. DFT+U+SOC calculations on cation ordering confirm the tendency toward the inverse spinel structure with increasing Fe concentration in CoV2–xFexO4 that starts to dominate already at low Fe contents. The theoretical results also show that the variations of oxidation states are related to the surface region, where the redox activity was found experimentally to be manifested in the transformation of V3+ → V2+. The high catalytic activity, facile synthesis, and low cost of the CoV2–xFexO4 nanoparticles render them very promising for application in bifunctional electrocatalysis.
中文翻译：
均匀高分散钴钒铁尖晶石纳米晶体的组成在氧电催化中的作用
过渡金属氧化物中的阳离子取代是通过优化其组成来改善电催化剂的重要途径。在此，我们在相纯尖晶石型报告CoV的2- X的Fe X ö 4纳米颗粒与0≤ X ≤2作为一类新的析氧（OER）和氧还原反应（ORR）双功能催化剂。混合金属氧化物催化剂对OER和ORR都具有很高的催化活性，这在很大程度上取决于V和Fe的含量。已知CoV 2 O 4具有高电导率，而在CoFe 2 O 4中由于尖晶石结构的反转，钴阳离子分布有望发生变化。优化的催化剂CoV 1.5 Fe 0.5 O 4在10 mA cm –2时的OER的超电势约为300 mV，在碱性电解液中的Tafel斜率为38 mV dec –1。DFT + U + SOC对阳离子有序的计算证实了随着CoV 2– x Fe x O 4中Fe浓度的增加，尖晶石结构趋向于反向的趋势。在低铁含量下已经开始占主导地位。理论结果还表明，氧化态的变化与表面区域有关，在实验中发现氧化还原活性在V 3+ →V 2+的转变中得以体现。CoV 2– x Fe x O 4纳米颗粒的高催化活性，易于合成和低成本使得它们非常有希望在双功能电催化中应用。
更新日期：2018-01-18
中文翻译：
均匀高分散钴钒铁尖晶石纳米晶体的组成在氧电催化中的作用
过渡金属氧化物中的阳离子取代是通过优化其组成来改善电催化剂的重要途径。在此，我们在相纯尖晶石型报告CoV的2- X的Fe X ö 4纳米颗粒与0≤ X ≤2作为一类新的析氧（OER）和氧还原反应（ORR）双功能催化剂。混合金属氧化物催化剂对OER和ORR都具有很高的催化活性，这在很大程度上取决于V和Fe的含量。已知CoV 2 O 4具有高电导率，而在CoFe 2 O 4中由于尖晶石结构的反转，钴阳离子分布有望发生变化。优化的催化剂CoV 1.5 Fe 0.5 O 4在10 mA cm –2时的OER的超电势约为300 mV，在碱性电解液中的Tafel斜率为38 mV dec –1。DFT + U + SOC对阳离子有序的计算证实了随着CoV 2– x Fe x O 4中Fe浓度的增加，尖晶石结构趋向于反向的趋势。在低铁含量下已经开始占主导地位。理论结果还表明，氧化态的变化与表面区域有关，在实验中发现氧化还原活性在V 3+ →V 2+的转变中得以体现。CoV 2– x Fe x O 4纳米颗粒的高催化活性，易于合成和低成本使得它们非常有希望在双功能电催化中应用。
京公网安备 11010802027423号