Qianran Feng,Xiaoting Yu,Jinlian Peng,Siying Du,Liuyun Chen,Xinyuan Xu,Tongming Su
Sustainable production of hydrogen is currently a global research hotspot. In this study, a Ni(OH)2cocatalyst was loaded on Zn0.8Cd0.2S to form Ni(OH)2/ZCS composites and achieve highly efficient photocatalytic hydrogen production. After Ni(OH)2loading, a close contact interface was established between Ni(OH)2and Zn0.8Cd0.2S, which increased the separation efficiency of the photogenerated electrons and holes. Moreover, the addition of Ni(OH)2increases the specific surface area and light absorption of Ni(OH)2/Zn0.8Cd0.2S, and the Ni(OH)2can act as active sites for photocatalytic hydrogen production. The photocatalytic H2production rate of Ni(OH)2/ZCS composites increases with the increase in the Ni amount. 9Ni(OH)2/ZCS exhibited the optimum H2production rate of 12.88 mmol h−1g−1, which was 9.9 times higher than that of Zn0.8Cd0.2S. When the amount of Ni(OH)2is further increased, the excess Ni(OH)2covers the active site of Zn0.8Cd0.2S and reduced the light absorption of Zn0.8Cd0.2S, resulting in a decrease in the H2production rate. Furthermore, the H2production rate of 9Ni(OH)2/ZCS decreased from 12.88 to 5.15 mmol g−1h−1after 3 cycles. The main reason for the decline in the photocatalytic performance of Ni(OH)2/ZCS is the photocorrosion of Zn0.8Cd0.2S. This study provides an innovative design for loading Ni(OH)2cocatalysts on Zn0.8Cd0.2S to improve the performance of photocatalysts.
Ying Luo,Xiaohui Zhang,Cheng Huang,Xiaole Han,Qingqing Jiang,Tengfei Zhou,Haijian Yang,Juncheng Hu
Facilitating charge separation and increasing surface active sites have always been the goals of photocatalysis. Herein, we synthesized a Ni-doped Zn0.8Cd0.2S hollow sphere photocatalyst with a facile one-step hydrothermal method. Energy-dispersive spectroscopy mapping showed the high dispersion of Ni ions in the Zn0.8Cd0.2S hollow spheres. The experimental results confirmed that Ni doping reduced the band structure of the substrate, suppressed the recombination of photo-induced electrons and holes, and provided more reactive sites. Therefore, the photocatalytic activity had been greatly improved. As a consequence, the detected photocatalytic H2 evolution rate increased up to 33.81 mmol·h–1·g–1 over an optimal Ni doping (5 wt %) of Zn0.8Cd0.2S hollow spheres, which was 20.87-fold higher than that of pure CdS. Elemental mapping showed that the Zn element was mainly distributed in the outermost layer of the hollow spheres; this might be the critical factor that enabled Ni-doped ZnxCd1–xS to maintain excellent stability.
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