CoP-Embedded Graphitic N-Doped C Nanosheets in Ohmic Contact with S-Deficient CdS Nanocrystals Triggering Efficient Visible-Light Photocatalytic H2 Evolution

Abstract

Photocatalytic water splitting using semiconductor-based catalysts is a promising avenue to gain H2 fuel from renewable solar energy. Nonetheless, developing earth-abundant and visible-light-responsive photocatalysts for efficient H2 production still remains a huge challenge. In this work, unique two-dimensional hierarchitectures of S-deficient CdS integrated with ultrafine CoP nanocrystals embedding in graphitic N-doped C (CoP-CN) nanosheets are fabricated for the first time. Noticeably, the graphitic CN electron mediator not only enhances the photocatalytic stability of CdS/CoP-CN composites by protecting CoP from external corrosion but also induces the formation of an ohmic junction to boost electron extraction from CdS to CoP efficiently. Meanwhile, the S vacancies in CdS serve as electron traps to further enhance the separation of photogenerated carriers. Such unique CdS/CoP-CN hierarchical hybrid nanosheets exhibited an extraordinary visible-light-induced (λ > 400 nm) photocatalytic H2-evolving performance, delivering a high apparent quantum yield (26.3% at 420 nm) and an excellent H2 generation rate of 54.01 mmol·g–1·h–1, much superior to those of a CdS/CoP Schottky junction, Pt-loaded CdS, and a vast amount of CdS-based photocatalysts ever reported. In addition, the outstanding H2-evolving durability of CdS/CoP-CN composites was verified by cycling and long-term photocatalytic tests. The findings presented here are anticipated to enlighten the rational design and synthesis of highly active photocatalysts with an ohmic junction for application in energy and environment-related domains.