表面羟基化 BiVO4 光阳极上增强的光电化学水氧化：有利的电荷分离和水离解,New Journal of Chemistry

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表面羟基化 BiVO4 光阳极上增强的光电化学水氧化：有利的电荷分离和水离解
New Journal of Chemistry ( IF 2.7 ) Pub Date : 2022-11-21 , DOI: 10.1039/d2nj04470f
Yaru Li ₁ , Fangxia Xie ₁ , Zijun Sun ₁ , Zhuobin Yu ₂ , Jianxin Liu ₁ , Xiaochao Zhang ₁ , Yawen Wang ₁ , Yunfang Wang ₁ , Rui Li _{1,

3} , Caimei Fan ₁

Affiliation

钒酸铋（BiVO ₄）是最有效的光电化学水分解光阳极材料之一，但其反应速率受到光生电荷分离效率低和动力学缓慢的极大限制。在这项工作中，进行了表面羟基化策略以克服上述缺点。一种简单的合成后 NaOH 浸泡方法被用来成功地羟基化 BiVO ₄光阳极表面而不影响其体积特性。修饰的表面羟基不仅提高了羟基化BiVO ₄的光生电荷分离效率，而且调整了其局部电子结构以形成高价Bi ^{(3+ x )+}状态。作为活性位点的 Bi ^{(3+ x )+}物种有利于水的离解，从而降低了潜在决定步骤的自由能势垒，从而提高了水的整体氧化动力学。结果，最好的羟基化 BiVO ₄光阳极在可见光照射下在 1.23 V vs. RHE 下实现了 1.14 mA cm ^-2的更高光电流密度，这是裸 BiVO ₄ (0.24 mA cm ^-2 ) 的 4.75 倍，并且此外，在 1 mA cm ^{-2时，阴极位移为 190 mV}获得。我们的工作提供了一种实用的方法，具有很强的可操作性，可以通过有效的表面羟基化策略来提高光阳极的本征光电化学性能。

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Enhanced photoelectrochemical water oxidation over a surface-hydroxylated BiVO4 photoanode: advantageous charge separation and water dissociation

Bismuth vanadate (BiVO₄) is one of the most effective photoanode materials for photoelectrochemical water splitting, but its reaction rate is greatly limited by the poor separation efficiency of photo-generated charges and sluggish kinetics. In this work, a surface hydroxylation strategy was carried out to overcome the above-mentioned shortcomings. A simple post-synthetic NaOH immersion method was used to successfully hydroxylate the BiVO₄ photoanode surface without affecting its bulk properties. The modified surface hydroxyl group not only promotes the photo-generated charge separation efficiency of hydroxylated BiVO₄ but also tailors its local electronic structure to form high-valence Bi^(3+x)+ states. The Bi^(3+x)+ species serving as the active site is advantageous for water dissociation, thus decreasing the free energy barrier of the potential-determining step for the boosted overall water oxidation kinetics. As a result, the best hydroxylated BiVO₄ photoanode achieves a higher photocurrent density of 1.14 mA cm⁻² at 1.23 V vs. RHE under visible light irradiation, which is 4.75 times that of bare BiVO₄ (0.24 mA cm⁻²), and moreover, a cathodic shift of 190 mV at 1 mA cm⁻² is obtained. Our work affords a practical method with strong operability to improve the intrinsic photoelectrochemical performance of photoanodes by the efficient surface hydroxylation strategy.

更新日期：2022-11-21

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