Two-Dimensional High-Entropy Selenides for Boosting Visible-Light-Driven Photocatalytic Performance

High-entropy materials (HEMs) have garnered extensive attention owing to their diverse and captivating physicochemical properties. Yet, fine-tuning morphological properties of HEMs remains a formidable challenge, constraining their potential applications. To address this, we present a rapid, low-energy consumption diethylenetriamine (DETA)-assisted microwave hydrothermal method for synthesizing a series of two-dimensional high-entropy selenides (HESes). Subsequently, the obtained HESes are harnessed for photocatalytic water splitting. Noteworthy is the optimized HESes, Cd_0.9Zn_1.2Mn_0.4Cu_1.8Cr_1.2Se_4.5, showcasing an output rate of hydrogen of 16.08 mmol h^-1 g^-1 and a quantum efficiency of ca. 30% under 420 nm monochromatic LED irradiation. It is revealed that the photocatalytic performance of these HESes stems not only from the enlarged specific surface area and enhanced photogenerated charge carrier utilization efficiency but also from the promoted formation of the Cd-H_ads bond, influenced by multiple principal elements on the Cd. These findings provide a guide for the design of HEMs tailored for various applications.