摘要
金属助催化剂负载对提高二氧化钛(TiO2)的光催化制氢性能起着关键作用,金属负载TiO2形成肖特基结能有效促进载流子的分离和迁移,双金属相比单一金属通常具有更优越的助催化性能,不同金属的组合提供了克服单一金属局限性的方法.制备了系列CuxZny双金属负载的TiO2(CuxZny/TiO2)催化剂材料,并进行光催化制氢研究.锌(Zn)可以延长光激发电子的寿命;铜(Cu)不仅可以提高载流子迁移效率,表面等离子体共振效应还可有效捕获太阳光中的红外光,将红外光转化为热能用于促进制氢反应.此外,Cu和Zn的协同效应使CuxZny双金属的助催化效果显著优于单一金属Cu或Zn,更有效抑制了 TiO2光生载流子的复合,提高了载流子的利用率,进一步提高了对太阳光的利用率.Cu3Zn3/TiO2的光催化制氢速率最高,达到了 3 726 μmol·g-1·h-1,是纯TiO2光催化制氢速率的5.9倍.研究结果为设计双金属助催化剂和光热耦合催化提供了重要的研究思路.
Abstract
Metal cocatalyst plays a key role in improving the photocatalytic hydrogen production performance of TiO2 as the formation of Schottky junctions by metal-supported TiO2 can effectively promote the separation and migration of charge carriers.Bimetals usually have better cocatalytic performance than single metals,and the combination of different metals provides a way to overcome the limitations of single metals.Therefore,a series of bimetallic CuxZny supported TiO2(CuxZny/TiO2)photocatalysts were prepared for boosting photocatalytic hydrogen production.Zn can prolong the life span of photoexcited electrons.Cu does not only improve the migration of charge carriers,its surface plasmon resonance effect can effectively capture and convert the infrared light into heat energy for promoting hydrogen production reaction.The synergistic effect between Cu and Zn results in the CuxZny bimetal exhibiting significantly better cocatalytic performance than single Cu or Zn metals,more effectively inhibiting the recombination of photogenerated carriers in TiO2 and improving the utilization of these carriers,thereby further enhancing the utilization of sunlight.Cu3Zn3/TiO2 shows the highest photocatalytic hydrogen production rate of 3 726 μmol·g-1·h-1,which is 5.9 times that of pure TiO2.This study provides an important reference for the design of bimetallic cocatalysts and photothermal coupled catalysis.
万方数据