Self-optimizing bifunctional CdS/Cu2S with coexistence of light-reduced Cu0 for highly efficient photocatalytic H2 generation under visible-light irradiation
Self-optimizing bifunctional CdS/Cu2S with coexistence of light-reduced Cu0 for highly efficient photocatalytic H2 generation under visible-light irradiation
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DOI：
10.1016/j.apcatb.2017.05.074
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发表时间：
2017-11
影响因子：
22.1
通讯作者：
Jiajun Zhang;Weisong Li;Ye Li;Lei Zhong;Chunjian Xu
中科院分区：
文献类型：
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作者：
Jiajun Zhang;Weisong Li;Ye Li;Lei Zhong;Chunjian Xu
采用简单的两步溶剂热法合成了具有高活性和高稳定性的自优化双功能核壳结构的CdS/Cu2S异质结，用于可见光照射下的光催化析氢。与纯Cd S相比，杂化材料的光催化活性显著提高了近25倍。样品CdS/Cu2S-30的最大析氢速率为14.4mmol.h−1g−1，在420 nm处的表观量子产率为19.5%。通过扫描电子显微镜和电子显微镜观察发现，Cu2S完全覆盖了单晶CdS纳米棒的表面，缩短了载流子的径向转移路径，增加了催化剂的反应表面积，有利于催化剂的活性。这种光催化剂兼具双功能和自优化功能。在光反应过程中，部分Cu2S被辐射到Cu2S核与Cu2S壳之间的表面还原为CuO，而其余的Cu2S为析氢反应(HER)提供了大量的活性中心。这些生成的CuO通过形成多异质结来延缓载流子复合过程。同时，通过催化剂表面的Cu/Cu2S比自动变化到最佳值以适应相应的反应条件，实现了该光催化剂的自优化。在这些优点的基础上，促进了析氢反应。
A self-optimizing bifunctional core-shell CdS/Cu2S heterojunction with high activity and superb stability for the photocatalytic hydrogen evolution under visible light irradiation was synthesized by a simple two-step solvothermal method. Compared with pure CdS, the photocatalytic activity of the hybrid is significantly enhanced by almost 25 times. The sample CdS/Cu2S-30 has shown a maximum H2evolution rate of 14.4 mmol h−1g−1with an apparent quantum yield of 19.5% at 420 nm. The surface of single-crystalline CdS nanorod is fully covered by Cu2S, observed via SEM and TEM, which benefits the activity of catalyst by shorting radial transfer path of charge carriers and increasing the surface area for reaction. This photocatalyst features both bifunction and self-optimizing. During photo reaction, part of Cu2S is reduced to Cu0by irradiation on the surface between CdS core and Cu2S shell, while the rest of Cu2S offers plenty of active sites for hydrogen evolution reaction (HER). These generated Cu0retard the charge carrier recombination process by forming multi-heterojunction. Meanwhile, the self-optimizing of this photocatalyst is realized by Cu/Cu2S ratio on the surface of catalyst varying automatically to the optimal value to adapt to the corresponding reaction condition. Based on all these benefits, hydrogen evolution reaction is facilitated.