Atomically dispersed scandium Lewis acid sites on carbon nitride for efficient photocatalytic hydrogen peroxide production
Atomically dispersed scandium Lewis acid sites on carbon nitride for efficient photocatalytic hydrogen peroxide production
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DOI：
10.1007/s40843-022-2185-1
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发表时间：
2022-09
期刊：
影响因子：
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通讯作者：
S. Yao;Ting Tang;Yongli Shen;F. Yang;Changhua An
中科院分区：
文献类型：
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作者：
S. Yao;Ting Tang;Yongli Shen;F. Yang;Changhua An
光催化氧气还原法具有节能、环保等优点，是一种很有前途的制备过氧化氢的方法。然而，光催化剂的低活性和选择性阻碍了其实际应用。本文根据金属离子耦合电子转移原理，采用原子分散的钪刘易斯酸（Sc/H-CN）修饰石墨碳氮化物（g-C_3 N_4）。合成的Sc/H-CN具有优异的H2 O2生成性能，其速率为55 µmol h−1，是裸CN的6.2倍。这是由于Sc的刘易斯酸中心与中间体·O2−结合，抑制了O2的逆反应，从而提高了O2的电子接受能力。此外，密度泛函理论（DFT）计算和Koutecky-Levich分析表明，减少的O-O键断裂是H2 O2生产中高选择性的原因。这为设计具有合适活性位的光催化剂提供了一种新的策略。
Photocatalytic reduction of oxygen represents a promising way to produce hydrogen peroxide (H2O2) owing to the merits of energy saving and environmental benignancy. However, the low activity and selectivity of the photocatalyst impede its practical application. Herein, following the principle of metal ion-coupled electron transfer, we have fabricated a class of graphitic carbon nitride (g-C3N4) decorated with atomically dispersed scandium Lewis acid (Sc/H-CN) using a facile impregnation-calcination method. The as-synthesized Sc/H-CN exhibits excellent H2O2production performance with a rate of 55 µmol h−1, which is 6.2 times over bare CN. The improved performance is ascribed to the enhancement of O2electron-accepting capability through binding of Sc Lewis acid sites with intermediate ·O2−, inhibiting its reverse reaction. Moreover, density function theory (DFT) calculation and Koutecky-Levich analysis show that the reduced O−O bond breakage is responsible for the high selectivity in the production of H2O2. This work provides a new strategy for the design of photocatalysts equipped with appropriate active sites towards various applications.