Efficient Catalytic Preparation Of Benzyl Alcohol By Bimetallic Composite Photocatalyst Hydrogen And Benzaldehyde

With the continuous development of society,the major evolutionary challenges caused by energy shortages have led to an urgent need for sustainable and environmentally friendly energy.As hydrogen combustion does not produce harmful substances to the environment,it greatly reduces greenhouse gas emissions.Hydrogen fuel as a clean energy has received widespread attention.However,traditional fossil fuels still dominate the energy demand in daily life.Photocatalytic hydrogen production provides a new pathway for clean energy production in the future.Currently,photocatalytic hydrogen production technology involves the catalytic production of hydrogen from water and sacrificial agents under illumination.However,inherent drawbacks such as high thermodynamic barriers and slow kinetic rates limit the photocatalytic activity.Therefore,it is necessary to find an alternative sacrificial agent that utilizes photo-generated holes for oxidation.This strategy can not only improve catalytic efficiency but also convert solar energy into chemical energy and other chemicals.This work describes the significantly improved efficiency of converting solar energy into chemical energy and additional chemicals by modifying the traditional semiconductor catalysts of cadmium sulfide(CdS)and graphitic carbon nitride(g-C3N4)with bimetallics.The main content is as follows:(1)A composite photocatalytic material consisting of CdS nanorods loaded with Cu-Ni bimetal was synthesized by a simple hydrothermal reduction method.CdS was used as a model semiconductor due to its matched redox potential,strong ability to provide electron-hole pairs,enhanced absorption of visible light,and efficient charge carrier generation.The composite catalyst showed significant visible light photocatalytic activity for the dissociation of benzyl alcohol(BA).Compared to pure CdS nanorods,Cu-Ni loaded CdS exhibited higher photocatalytic activity,and the best 20%CuiNii/CdS nanocomposite material had a hydrogen production efficiency and benzaldehyde(BAD)yield that were 8.7 times higher.This improvement in photocatalytic efficiency can be attributed to the synergistic effect of CuNi bimetal,which greatly enhances the separation efficiency of photogenerated electrons and holes.(2)Copper and nickel complexes were prepared through two reactions,and then g-C3N4 was successfully synthesized in situ with the two complexes using a tube furnace to prepare the CuNi/CN composite photocatalyst.The composite photocatalyst 2%Cu1Ni1/CN exhibited high activity(80 μmol g-1 h-1)and selectivity for the dehydrogenation of aromatic alcohols,with better catalytic efficiency than traditional CN.Nitrogen-doped carbon nanosheets provided an instantaneous charge transfer pathway,while the loaded bimetallic CuNi provided abundant active sites.The intimate interface contact between the nitrogen-doped carbon nanosheets and the CuNi bimetallic catalyst significantly improved its photocatalytic efficiency.Moreover,the bimetallic CuNi broadened the absorption range of light,accelerated the separation and migration efficiency of photoinduced charge carriers,and significantly improved the photocatalytic performance.This work verifies that the rational construction of non-precious metal composite photocatalytic materials has promising prospects.Furthermore,the rational construction of non-precious metal composite photocatalytic materials enables the efficient synthesis of fine chemicals by photocatalysis and the production of solar fuels.(3)A new ternary CdS/CuNi/CN composite material was designed and synthesized using chemical deposition and hydrothermal methods.Compared with g-C3N4,the ternary photocatalyst has significantly enhanced photocatalytic activity.The results show that the 40%CdS/5%CuNi/CN photocatalyst exhibits the best hydrogen production performance,reaching up to 8.61 mmol g-1 h-1.The enhanced catalytic efficiency can be attributed to the following factors:(ⅰ)extended light absorption range;(ⅱ)synergistic effect of CuNi bimetallic;(ⅲ)suitable conduction and valence band structure,which inhibits the recombination of photogenerated electrons and holes.These factors greatly improve the catalytic efficiency of the composite photocatalyst.This work also opens up a new way to design efficient ternary photocatalytic systems.