Selenium-Rich Configuration And Amorphization For Synergistically Maximizing The Active-Center Amount Of Cose1+X Nanodots Toward Efficient Photocatalytic H-2 Evolution

Transition-metal selenides have been evidenced to be promising candidates for efficient H-2 evolution cocatalysts due to a similar Se-H-ads (273 kJ/mol) bond energy to Pt-H (251 kJ/mot), while their H-2 evolution activity is still limited by the insufficient exposure of active Se atoms. Herein, a synergic idea of selenium-rich configuration and amorphization was developed to construct selenium-rich amorphous CoSe1+x nanodots for maximum exposure of more hydrogen-production selenium sites. For this purpose, the selenium-rich amorphous CoSe, nanodots with an ultrasmall size (0.2-1 nm) and selenium-rich character can be resourcefully and uniformly grafted with a TiO2 photocatalyst via the facile photoinduced electron-reduction way. Photocatalytic results showed that the as-prepared selenium-rich a-CoSe1+x/TiO2 (0.5 wt %) attains a maximal hydrogen production activity (3400 mu mol h(-1) g(-1), AQE = 16.3%), which is significantly superior to those of crystalline c-CoSe/TiO2 and conventional amorphous a-CoSe/TiO2 samples by a factor of 3.2 and 1.6 times, respectively. The outstanding activity can be ascribed to the cooperation of accelerated photoinduced electron migration from TiO2 to a-CoSe1+x and rapid hydrogen evolution on the enriched active Se sites. Meaningfully, the selenium-rich a-CoSe1+x can also be employed as the general H-2 evolution electron cocatalyst for CdS and g-C3N4 photocatalysts. This work sheds light on the ingenious design and construction of efficient and inexpensive active-site-rich cocatalysts for highly active photocatalytic materials.