Recently, Li Can, a member of the Chinese Academy of Sciences, Institute of Solar Energy Research, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, and researcher Zhang Fuxiang, etc., have made new progress in the study of hydrogen production from the broad-spectrum light-harvesting catalyst Z mechanism. The study found that by designing and regulating the surface of BiVO4 The support of the catalyst Au and the selective loading of the double promoter (Au and CoOx) can effectively promote the oxygen production performance of BiVO4 and the charge transfer between the redox and the ion, and build a highly efficient visible light based on this. The mechanism of total decomposition of water system, its apparent quantum efficiency exceeds 10% (420nm excitation). The relevant results were published online in the Joule journal of Cell.
The realization of solar energy total decomposition of hydrogen based on photocatalyst powder suspension system is expected to become one of the economically viable solar energy conversion methods. In recent years, Li Can and Zhang Fuxiang team have been working to construct a Z-system full decomposition water system using broad spectrum response materials, during which time 'One-pot nitriding' constructs a heterojunction to promote charge separation. It solves the experimental problem that the nitrogen-containing compound has poor thermal stability under air or inert gas, and it is difficult to construct a heterojunction, and then constructs multiple Z-systems. Water hydrogen production system (Angew. Chem. Int. Ed., Chem. Sci.). In addition, the team developed a new method for ammonia flow protection of supported oxygen release promoters, greatly enhancing the oxygen release of broad spectrum light-harvesting catalysts. On the basis of this, it is found that the dispersibility of the cocatalyst has a great influence on the interfacial charge separation, which is obviously affected by the hydrophilic and hydrophobic properties of the interface. For example: modification of the surface magnesium oxide layer by Ta3N5 can not only promote the dispersion of the promoter and the interface charge. Separation efficiency, and can effectively inhibit the competitive reaction in the Z mechanism, and finally make it possible to fully decompose water to hydrogen production by the Z mechanism (related results are published in J. Am. Chem. Soc., Angew. Chem. Int. Ed., J. Catal., Appl Catal B: Environ. et al.) Through continuous efforts, the team not only successfully expanded the Z mechanism to fully decompose water to produce hydrogen and hydrogen. The range of utilization of visible light on the oxygen-producing end catalyst (the hydrogen-producing end is extended from 510 nm to 650 nm; the oxygen-generating end is extended from 450 nm to 590 nm), and the apparent quantum efficiency record of the powder system Z-visible light-catalyzed full-decomposition water hydrogen production is continuously refreshed. .
This study uses 'Fe(CN)6'3-/'Fe(CN)6'4- with a single electron transfer, suitable for neutral environment and has a lower redox potential, as a redox couple, based on its preliminary experiments. , Photoelectron and hole space separation between different crystal planes of BiVO4 (Nature Commun.), selective deposition strategy of double promoter (Au/CoOx) on {010} and {110} planes of BiVO4 to produce oxygen The performance is greatly improved. On the basis of this, by coupling the hydrogen-producing end with wide visible light response, the efficient Z-system full-decomposition water is realized, and the quantum efficiency of total decomposition water hydrogen production of 10.3% (420 nm excitation) is obtained. The team previously maintained a record of 6.8% (420nm excitation). In addition, the study also found that the loading of Au nanoparticles is beneficial for the transfer of electrons from BiVO4 to 'Fe(CN)6'3-. The above results are further developed in the future. The high-efficiency visible light completely decomposes the water system and lays the foundation.
The research work was funded by the Fund Committee, the Ministry of Science and Technology, the Chinese Academy of Sciences, and the Collaborative Innovation Center for Energy Materials Chemistry.
