AuCu双金属合金修饰共价有机框架用于高效光催化析氢

Bimetallic AuCu Alloy Decorated Covalent Organic Frameworks for Efficient Photocatalytic Hydrogen Production

共价有机框架(COFs)是一种具有π-π共轭结构和分子结构可调的晶体多孔有机材料,在光催化领域具有广阔的应用前景。然而,未改性的COFs材料具有反应动力学缓慢的缺点,因此需要引入助催化剂以降低其表面催化反应的势垒,从而加速反应过程。此工作中,采用双金属合金作为助催化剂,以提高COFs的光催化析氢性能。通过调控AuCu合金的比例,发现Au_(1)Cu_(5)/COF-TpPa具有最高的光催化产氢速率(8.24 mmol·g^(-1)·h^(-1)),甚至高于Pt修饰的COF-TpPa的产氢速率(6.51 mmol·g^(-1)·h^(-1))。经过系统性的表征测试和理论计算分析,Au_(1)Cu_(5)/COF-TpPa表现出高的载流子分离效率和低的H^(*)生成能垒,从而具有高的光催化性能。本研究为利用双金属合金改性COF基光催化剂奠定了理论基础。

Covalent organic frameworks(COFs)represent a kind of novel crystalline porous organic substances with extended π-conjugation framework and tunable structures,which display great promise in photocatalysis.However,unadorned COFs suffer from sluggish reaction kinetics,and a cocatalyst is essentially needed to reduce the activation barrier toward specific surface reaction and accelerate reaction kinetics.In this work,bimetallic alloys serving as co-catalysts were decorated on COFs to enhance the photocatalytic hydrogen evolution performance.By precisely-tuning the ratio of AuCu alloy,the resultant Au_(1)Cu_(5)/COF-TpPa displays the highest photocatalytic hydrogen generation rate(8.24 mmol·g^(-1)·h^(-1)),even surpassing the Pt modified COF-TpPa(6.51 mmol·g^(-1)·h^(-1)).According to the systematic characterizations and theoretical calculation,Au_(1)Cu_(5)/COF-TpPa exhibits the significantly enhanced charge carrier separation efficiency and reduced H^(*)formation energy barrier,thus possessing high photocatalytic performance.This work affords a valuable approach to advancing COF-based photocatalysts by employing bimetallic alloy cocatalysts.