Crystral Facet Engineering Of Delafossite Catalyst AgGaO₂ And The Application In Photocatalytic Organic Synthesis

Delafossite（ABO₂）is an important class of functional oxides,rich A and B ion selection provides sufficient freedom for the regulation of its physicochemical properties,which is conducive to the design of high-performance catalysts,and is regarded as a promising functional material in the field of optoelectronics.Among them,delafossite materials with Ag as the cation A position are widely used in photocatalytic CO₂reduction,alcohol oxidation,water treatment and other research fields due to their adjustable band gap and band position.However,its poor stability and the need for precious metal cocatalysts and other shortcomings have led to little reporting of delafossite catalysts in organic synthesis.The photocatalyst represented by TiO₂can enhance the photocatalytic activity through crystal plane regulation,so this paper takesα-AgGaO₂as the research object,optimizes the catalyst catalytic performance through crystal plane regulation,and studies the reaction process of photocatalytic synthesis of high value-added coupling products,and the specific work content is as follows:1.By regulating the synthesis conditions,theα-AgGaO₂photocatalyst with different crystal faces was successfully prepared.The material characterization results show that the higher the alkali concentration during the preparation process,theα-AgGaO₂morphology is flattened（F-AGO）,and the low concentration alkali is stretched（S-AGO）.2.The catalyst of the above characteristic crystal plane was applied to the C-C bond reduction coupling of benzyl bromide and the N-N bond oxidative coupling of aniline.The test results show that F-AGO with a larger（001）crystal surface is more suitable for reduction reaction,while S-AGO with a larger（012）crystal surface is conducive to oxidation.Further N-N bond reductive coupling of nitrobenzene and C-N bond oxidative coupling of benzylamine and substrate expansion verified that F-AGO and S-AGO have good universality for photocatalytic reductive coupling and oxidative coupling,respectively.3.Through the light deposition support oxidation co-catalyst（MnO_x）and the reduction co-catalyst（Au）,combined with electrochemical impedance test analysis,the mechanism of crystal plane regulation on the redox performance ofα-AgGaO₂was explored.The results of theoretical calculations show that the built-in electric field formed by light hinders the internal migration of photogenerated electrons,so that the（001）crystal surface becomes an electron enrichment surface,which is conducive to photocatalytic reduction reaction,while the（012）crystal plane as a hole enrichment surface is conducive to photocatalytic oxidation.