Brewer 金属间相 Mo6Co7、W6Co7 和 W6Fe7 对析氢和析氧反应的电催化活性,Chemistry of Materials

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Brewer 金属间相 Mo6Co7、W6Co7 和 W6Fe7 对析氢和析氧反应的电催化活性
Chemistry of Materials ( IF 7.2 ) Pub Date : 2024-02-29 , DOI: 10.1021/acs.chemmater.4c00076
Yan Yang _{1,

2} , Ruxin Deng ₁ , Chaonan Wang ₁ , Jingtong Sun ₁ , Abishek K. Iyer ₂ , Craig C. Laing ₂ , Huiqin Yao ₃ , Shulan Ma ₁ , Mercouri G. Kanatzidis ₂

Affiliation

为了了解包含早期和晚期过渡金属的 Brewer 金属间相内的电催化活性趋势，我们合成了三种二元晶体金属间化合物，即 Mo ₆ Co ₇、W ₆ Co ₇和 W ₆ Fe ₇。金属间化合物在电化学水分解中的析氢反应(HER)和析氧反应(OER)均表现出Mo ₆ Co ₇ > W ₆ Co ₇ > W ₆ Fe _{7的活性趋势。}Mo ₆ Co _{7在 HER 中在 80 mA cm}^–2的高电流密度下表现出超过 24 小时的稳定电催化活性，这凸显了其作为强大的制氢电催化剂的潜力。我们的观察强烈表明电催化性能主要由Mo ₆ Co ₇结构内的固有催化活性金属位点决定。密度泛函理论（DFT）计算表明，对于HER，后过渡金属如Co和Fe比早期过渡金属Mo和W更活跃，反映了Co>Mo>W和Co>Fe的活性顺序。态密度(DOS)图表明Mo ₆ Co ₇在费米能级表现出最高的电荷密度，超过了W ₆ Co ₇和W ₆ Fe ₇。就 OER 的速率决定步骤 (RDS) 而言，计算出的超电势与实验中观察到的活性趋势一致，其中 Mo ₆ Co ₇表现出比 W ₆ Co ₇和 W ₆ Fe ₇更高的活性。我们的结果为定制金属间化合物以优化水分解中 HER 和 OER 的电催化效率、稳定性和活性奠定了基础。

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Electrocatalytic Activity of the Brewer Intermetallic Phases Mo6Co7, W6Co7, and W6Fe7 for Hydrogen and Oxygen Evolution Reactions

In pursuit of understanding the electrocatalytic activity trends within Brewer intermetallic phases comprising early and later transition metals, we synthesized three binary crystalline intermetallics, namely, Mo₆Co₇, W₆Co₇, and W₆Fe₇. The intermetallics exhibit an activity trend of Mo₆Co₇ > W₆Co₇ > W₆Fe₇ for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) in electrochemical water splitting. The Mo₆Co₇ demonstrates stable electrocatalytic activity over 24 h under a high current density of 80 mA cm^–2 in HER, which highlights its potential as a robust electrocatalyst for hydrogen production. Our observations strongly suggest that the electrocatalytic performance is predominantly governed by intrinsic catalytic active metal sites within the Mo₆Co₇ structure. Density functional theory (DFT) calculations suggest that for HER, the later transition metals such as Co and Fe are more active than the early transition metals of Mo and W, reflecting the activity order of Co > Mo > W and Co > Fe. The density of states (DOS) diagram indicates that Mo₆Co₇ exhibits the highest charge density at the Fermi level, surpassing both W₆Co₇ and W₆Fe₇. In terms of the rate-determining step (RDS) for the OER, the calculated overpotentials align with an activity trend observed in experiments, where Mo₆Co₇ demonstrates greater activity compared to W₆Co₇ and W₆Fe₇. Our results provide a foundation for tailoring intermetallics to optimize electrocatalytic efficiency, stability, and activity for HER and OER in water splitting.

更新日期：2024-02-29

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