Guan Shundong, Fu Xiuli, Zhang Yu, Peng Zhijian
State Key Laboratory of Information Photonics and Optical Communications , School of Science , Beijing University of Posts and Telecommunications , Beijing 100876 , P. R. China . Email:
School of Science , China University of Geosciences , Beijing 100083 , PR China . Email:
Chem Sci. 2017 Dec 13;9(6):1574-1585. doi: 10.1039/c7sc03928j. eCollection 2018 Feb 14.
Co-catalysis is regarded as a promising strategy to improve the hydrogen evolution performance of semiconductor-based photocatalysts. But developing a simple and effective technique to achieve the optimal synergy between co-catalysts and host photocatalysts has been a great challenge. Herein, hybrid photocatalysts consisting of β-NiS modified CdS nanowires (NiS/CdS NWs) have been synthesized a simple and green hydrothermal route using CdS NWs as the template from thiourea and nickel acetate in the presence of sodium hypophosphite. As a result, a metal Ni intermediate was formed an electroless plating process assisted by HPO, which facilitated the growth of highly conducting flake-like β-NiS nanostructures onto the surface of the CdS NWs. With the optimal loading amount of NiS, the obtained NiS/CdS NWs present a record-high photocatalytic activity for H evolution in lactic acid aqueous solutions under visible light irradiation. At 25 °C, the rate of H evolution was measured as 793.6 μmol h (over a 5 mg photocatalyst sample), which is nearly 250-fold higher than that over pure CdS NWs, and the apparent quantum yield reached an exceptionally high value of 74.1% at 420 nm. The mechanism for the photocatalytic H evolution over the present NiS/CdS NWs was also proposed. This strategy would provide new insight into the design and development of high-performance heterostructured photocatalysts.
共催化被认为是提高基于半导体的光催化剂析氢性能的一种有前景的策略。但是，开发一种简单有效的技术以实现共催化剂与主体光催化剂之间的最佳协同作用一直是一项巨大的挑战。在此，以CdS纳米线（NiS/CdS NWs）为模板，通过简单绿色的水热法，在次磷酸钠存在下，由硫脲和醋酸镍合成了由β-NiS修饰的CdS纳米线组成的混合光催化剂。结果，在HPO辅助的化学镀过程中形成了金属Ni中间体，这促进了高导电性片状β-NiS纳米结构在CdS NWs表面的生长。在NiS负载量最佳的情况下，所获得的NiS/CdS NWs在可见光照射下对乳酸水溶液中的析氢表现出创纪录的高光催化活性。在25°C下，析氢速率为793.6 μmol h（基于5 mg光催化剂样品），这比纯CdS NWs的析氢速率高出近250倍，并且在420 nm处的表观量子产率达到了74.1%的极高值。还提出了当前NiS/CdS NWs上光催化析氢的机理。该策略将为高性能异质结构光催化剂的设计和开发提供新的见解。
