Renke Bi,Bing Han,Yijie Shen,Jialong Liu,Zhiyu Wang
Sunlight-driven photocatalytic overall water splitting (OWS) is a promising approach for solar-to-chemical energy conversion. However, its realization with a single photocatalyst by one-step excitation has been extremely limited due to the rapid recombination of photogenerated charges, slow surface redox kinetics, and undesired reverse reactions. Herein, we sought to enhance the OWS performance of SrTiO3 (STO) by exploring the synergistic effects of different kinds of metal/oxide dual cocatalysts. The results show that the Pt/CrOx-STO system had a superior activity, which achieved stoichiometric water splitting with H2/O2 evolution of 1814.17/1020.47 μmol g–1 h–1 under simulated sunlight, without using any sacrificial reagents. The enhanced efficiency can be attributed to the improved interfacial transport of photogenerated charges and the boosted surface kinetics. Importantly, the CrOx layer served as a selective membrane that prevented the O2 diffusion and facilitated H+ transport, while partially covering the highly active site of Pt nanoparticles, thus significantly inhibiting the reverse recombination reaction of H2 and O2. In particular, this dual catalyst system emphasized a low dependence on the properties of the substrate material and is therefore widely applicable and economical. This work demonstrated the potential of the Pt/CrOx dual cocatalyst modification strategy for optimizing photocatalytic OWS, providing a pathway toward selective and sustainable conversion of H2O to H2 and O2.
Metal sulfide photocatalysts have been leading edge for hydrogen evolution reaction (HER) and solar energy conversion due to their suitable electronic and optical properties. The efficiency of these photocatalysts is mostly restricted by slow transfer of photogenerated holes and sluggish water dissociation kinetics. Here, we proposed HER catalyst comprising of Pt-CrO x sites loaded on ZnCdS nanocrystal (ZnCdS/Pt-CrO x ) that employing a redox couple ( OH/OH − ) transport mechanism to efficiently relay of holes in alkaline media. The Pt sites provide optimal hydrogen adsorption energy and CrO x sites support water dissociation, which speed up water dissociation kinetics and leads to a noticeable enhance in HER (21.1 mmol g −1 h −1 ) and phenol degradation. Such efficient activity could be associated to a better mobility of redox couple and fast water dissociation kinetics in alkaline solution. These types of related works open pathways to generate hydrogen from the sea water, largest water source on earth.
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