Efficient hydrogen production performance of 1T-2H MoSe2/ MnxCd1-xS Z-type heterojunction photocatalysts under visible light

Abstract

Finding suitable co-catalysts to help metal sulfides achieve effective bulk phase and surface charge separation is the key to improving their photocatalytic performance. In this paper, two-phase 1T-2H MoSe2 was loaded onto the surface of Mn0.4Cd0.6S solid solution with a twin crystal structure, and the 1T-2H MoSe2/Mn0.4Cd0.6S Z-type heterojunction structure was successfully constructed to realize the high efficiency of hydrogen production in the visible light. The metallic properties of the 1T phase can significantly improve the catalytic activity of MoSe2. The transition from the 2H to the 1T phase can lead to the creation of extra defects, such as unsaturated Mo and Se, thereby increasing the number of active sites on the photocatalyst surface. The two crystalline phases are staggered and form homogeneous junctions within them in the twin crystalline structure Mn0.4Cd0.6S prepared under an alkaline environment, which gives it excellent bulk and charge separation properties. After loading, the 1T phase MoSe2 at the interface of MoSe2 and Mn0.4Cd0.6S can accelerate the charge separation between the interfaces, and the Z-type heterojunctions formed by the two and the better retention of useful excitation electrons and holes. The 1% 1T-2H MoSe2/Mn0.4Cd0.6S could achieve a notable hydrogen production rate of 12.34 mmol ∙ g−1 ∙ h−1, surpassing that of the Mn0.4Cd0.6S solid solution. This non-precious metal-loaded homojunction photocatalyst effectively harnesses solar energy to produce clean H2 under mild conditions, giving a promising prospect for practical applications and laying the groundwork for further exploration of MnxCd1-xS photocatalysts.

Keywords

• Photocatalytic hydrogen production
• 1T-2H MoSe2
• Twin crystal Mn0.4Cd0.6S
• Heterojunction