Composite photocatalyst and application thereof

Abstract

The invention relates to a composite photocatalyst and an application thereof. The composite photocatalyst comprises an N2 activation cocatalyst, a photogenerated hole capturing cocatalyst and a photocatalyst serving as a carrier and providing a photogenerated carrier; the N2 activation cocatalyst is alkaline earth metal oxide; the photo-generated hole trapping cocatalyst is CoOx or NiOx, whereinx is larger than or equal to 1 and smaller than or equal to 1.33; the photocatalyst serving as the carrier and providing the photo-generated carrier is TiO2 or / and g-C3N4. The composite photocatalysthas huge scientific value and practical significance for preparation of high-activity photocatalytic synthetic ammonia materials and construction of a mild and low-energy consumption photocatalytic synthetic ammonia system.

Description

technical field [0001] The invention belongs to the field of artificial nitrogen fixation and synthesis of ammonia, relates to a composite photocatalyst and its application, and is suitable for the fields of environment, energy, materials and the like. Background technique [0002] Nitrogen fixation is the second most important chemical process after photosynthesis in nature. People have been expecting a chemical nitrogen fixation system like nitrogenase, which can convert nitrogen and water in the atmosphere into ammonia at normal temperature and pressure. Theoretically, the ammonia synthesis reaction is a thermodynamically impossible spontaneous reaction, and the triple bond energy of the nitrogen molecule is 941KJ mol -1 , the first ionization potential is 15.58eV, which has very high stability, and its triple bond energy is the largest among all homonuclear diatomic molecules. 2 and H 2 O is converted to ammonia. At present, the industrial production of synthetic ammo...

AI Technical Summary

Problems solved by technology

However, H 2 Catalytic dissociation of O molecules and achieve the same 2 The combined proton transfer process is still the bottleneck restricting the realization of this reaction

[0003] In recent years, there have been some reports on the synthesis of ammonia by photocatalysis, but most of the selected catalysts are metal-metal oxides or metal oxides supporting noble metals, and the yield of ammonia is low, so its application has not been realized.

Its shortcomings are mainly reflected in: 1. It is necessary to regulate the energy band position of semiconductor photocatalytic materials, improve the utilization rate of light and the migration efficiency of photogenerated carriers, so that the surface electrons / holes migrating to the surface have stronger redox properties. 2. It is necessary to construct the N on the surface of the photocatalytic material 2 Activate the site and ensure its stability; 3.N 2 The formation of reduced products requires the coordination of H + The transfer of ions or protons, the general photocatalytic system chooses an organic sacrificial agent to provide H + Donors of ions or protons, but from an application point of view, sacrificial agents or solvents increase reaction costs and bring new problems such as "three wastes" emissions and treatment

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