Electrochemically Modifying the Electronic Structure of IrO2 Nanoparticles for Overall Electrochemical Water Splitting with Extensive Adaptability,Advanced Energy Materials

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Electrochemically Modifying the Electronic Structure of IrO2 Nanoparticles for Overall Electrochemical Water Splitting with Extensive Adaptability
Advanced Energy Materials ( IF 24.4 ) Pub Date : 2020-06-18 , DOI: 10.1002/aenm.202001600
Lu Li ₁ , Bin Wang ₁ , Gengwei Zhang ₁ , Guang Yang ₂ , Tao Yang ₁ , Sen Yang ₁ , Shengchun Yang _{1,

3}

Affiliation

Designing the electrocatalysts that are stable and active for extensively adaptable water splitting is highly desirable for developing hydrogen based energy. IrO₂ is a promising and widely used catalyst for the oxygen evolution reaction in commercial applications, but is rarely used for the hydrogen evolution reaction (HER), due to the high Gibbs free energy for hydrogen adsorption (ΔG _H*). Herein, an approach to modify the electronic structure of IrO₂ via cyclic voltammetry is proposed. In this process, Ir(+4) is partially reduced and trace Pt is simultaneously deposited on IrO₂, which greatly lowers the ΔG _H* and thus accelerates the reaction kinetics. The as‐prepared Pt–IrO₂/CC with low noble metal loading (36.6 µg cm⁻²_(Ir+Pt)) exhibits excellent HER activity with overpotentials of 5, 22, and 26 mV at 10 mA cm⁻² in 0.5 m H₂SO₄, 1 m KOH, and 1 m phosphate buffer solution, respectively, making it possible to organize an all‐IrO₂ based water electrolyzer. The Pt–IrO₂/CC||IrO₂/CC couple exhibits a promising activity and stability in pH‐universal conditions as well as natural seawater for H₂ production. Density function theory calculations reveal that the optimized electronic structure of IrO₂ balances the ΔG _H*, resulting in a much enhanced HER performance.

中文翻译：

电化学修饰IrO2纳米粒子的电子结构，以实现广泛的整体水分解能力

为了开发基于氢的能量，非常需要设计对于广泛适用的水分解而言稳定且有活性的电催化剂。IrO ₂是用于工业应用中的氧释放反应的有希望且广泛使用的催化剂，但是由于用于氢吸附的高吉布斯自由能（ΔG _{H *}），因此很少用于氢释放反应（HER ）。在此，提出了通过循环伏安法改变IrO ₂的电子结构的方法。在此过程中，Ir（+4）被部分还原，同时痕量Pt同时沉积在IrO _2上，这大大降低了ΔG _{H *}，从而加快了反应动力学。准备好的Pt–IrO₂具有低的贵金属负载/ CC（36.6微克厘米^-2_{（IR + Pt）的}）表现出优异的HER为5，22和26毫伏在10mA厘米的超电势活性^-2 0.5米ħ ₂ SO ₄，1个米分别使用KOH和1 m磷酸盐缓冲溶液，可以组织基于全IrO ₂的水电解槽。Pt–IrO ₂ / CC || IrO ₂ / CC对在pH通用条件下以及天然海水生产H _2中均显示出良好的活性和稳定性。密度泛函理论计算表明，优化的IrO电子结构_图2平衡了ΔG _{H *}，从而大大提高了HER性能。

更新日期：2020-08-11

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