Heterostructured CoP/MoO2 on Mo foil as high-efficiency electrocatalysts for the hydrogen evolution reaction in both acidic and alkaline media,Journal of Materials Chemistry A

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Heterostructured CoP/MoO2 on Mo foil as high-efficiency electrocatalysts for the hydrogen evolution reaction in both acidic and alkaline media
Journal of Materials Chemistry A ( IF 10.7 ) Pub Date : 2020/03/17 , DOI: 10.1039/c9ta13553g
Huihui Zhao _{1,

2,

3,

4} , Zhi Li _{1,

2,

3,

4} , Xiaoping Dai _{1,

2,

3,

4} , Meilin Cui _{1,

2,

3,

4} , Fei Nie _{1,

2,

3,

4} , Xin Zhang _{1,

2,

3,

4} , Ziteng Ren _{1,

2,

3,

4} , Zhaohui Yang _{1,

2,

3,

4} , Yonghao Gan _{1,

2,

3,

4} , Xueli Yin _{1,

2,

3,

4} , Yao Wang _{1,

2,

3,

4} , Weiyu Song _{1,

2,

3,

4}

Affiliation

Heterostructured CoP nanoarray/MoO₂ films on Mo foil (CoP–MoO₂/MF) were synthesized through a low-temperature phosphorization process using pre-oxidized MF supported cobalt hydroxide-carbonate nanoneedles as the precursor. Such a CoP–MoO₂/MF heterostructure exhibits superior HER performance with low overpotentials of 42 mV (alkaline) and 65 mV (acid) to achieve a current density of 10 mA cm⁻², robust stability, large exchange current density and high turnover frequency. The experimental characterization and DFT calculations reveal that the presence of MoO₂ leads to an inherent ability to adsorb water and cleave H–O bonds, favoring hydrogen transfer to accelerate the Volmer step. Heterointerfacial charge redistribution provides optimal hydrogen adsorption ability on adjacent P sites to boost the Heyrovsky step and, as a result, the hydrogen adsorption free energy (ΔG_H*) can be reduced from 0.08 eV on CoP (011) and −0.78 eV on MoO₂ (011) to 0.02 eV on the heterointerface of CoP–MoO₂, which significantly improves the HER activity and accelerates the catalytic kinetics. This work highlights the roles of the heterointerface in electrocatalysis and provides an avenue to design electrocatalysts.

中文翻译：

Mo箔上的异质结构CoP / MoO2作为在酸性和碱性介质中析氢反应的高效电催化剂

通过使用预氧化的MF负载的氢氧化钴-碳酸盐纳米针作为前体，通过低温磷化工艺，合成了Mo箔上的异质结构CoP纳米阵列/ MoO ₂膜（CoP–MoO ₂ / MF）。这种CoP–MoO ₂ / MF异质结构具有卓越的HER性能，低过电势（碱性）为42 mV（酸性）和65 mV（酸性），可实现10 mA cm ^-2的电流密度，稳定的稳定性，较大的交换电流密度和高转换率频率。实验表征和DFT计算表明MoO ₂的存在导致固有的吸附水和裂解H–O键的能力，有利于氢转移以加速Volmer步骤。杂界面电荷的重新分布可在相邻的P位上提供最佳的氢吸附能力，以增强Heyrovsky步骤，因此，氢吸附自由能（ΔG _{H *}）可以从CoP（011）上的0.08 eV降低到CoP（011）上的-0.78 eV CoP–MoO ₂异质界面上的MoO ₂（011）至0.02 eV ，可显着提高HER活性并加速催化动力学。这项工作突出了异质界面在电催化中的作用，并为设计电催化剂提供了途径。

更新日期：2020-04-08

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