Preparation Of BiOCl Composites And Study On Its Photocatalytic Performance

With the accelerated development of industrialization and urbanization in various countries,environmental pollution and energy shortage are two world-wide problems that have attracted the attention of society.Environmental pollution not only damages the ecosystem,but also indirectly influence human society,and this hazard may last for some time.In addition to the problem of environmental pollution,energy shortage is also one of the global concerns.Nowadays,the shortage of non-renewable resources in various countries has caused people to pay more attention to renewable energy.Sustained economic development and the urgent need for survival reasons have led countries to increase their efforts to develop renewable energy.As a technology that can solve the problem of environmental pollution and energy shortage,photocatalytic technology has attracted widespread attention from scientists in various countries.However,traditional inorganic photocatalytic materials have some shortages such as insufficient utilization of solar energy and low photon efficiency,which hinders the development of photocatalytic technology.Therefore,developing a photocatalyst which has high photocatalytic activity and high solar energy utilization is an urgent problem to be solved.As a layered structure semiconductor,bismuth oxychloride has the advantages of excellent optical performance,non-toxic,easy to obtain,and good chemical stability.Therefore,it has attracted the attention of researchers in the field of photocatalysis.But bismuth oxychloride still has shortcomings such as narrow light absorption range.Therefore,it is significant to prepare new material with high photocatalytic activity based on bismuth oxychloride.In this manuscript,bismuth nitrate pentahydrate,ethylene glycol,and ethanol were used to prepare bismuth oxychloride by hydrothermal reaction technology,and then use methods like build inorganic-inorganic heterojunction,organic-inorganic heterojunction,and modified use organic small molecule to improve the efficiency of photocatalysts.Three new types of photocatalysts were obtained,and their structure and photocatalytic performance were studied,respectively.(1)Build bismuth nitrate and bismuth oxychloride heterojunction.The results of hydrogen production show that the hydrogen production efficiency of Bi6O6(OH)3(NO3)3·1.5H2O/Bi OCl composite can reach to 6.27 ?mol·h-1·g-1,which are 11.31 times than pure Bi6O6(OH)3(NO3)3·1.5H2O(0.55 ?mol·h-1·g-1)and 6.36 times than pure Bi OCl(0.98 ?mol·h-1·g-1).This is mainly because the heterojunction structure between Bi6O6(OH)3(NO3)3·1.5H2 O and Bi OCl improves the efficiency of electron-hole separation,thereby promoting charge transfer.(2)Build bismuth oxychloride and g-C3N4 heterojunction.Analyze the effect of different content of raw material ratio on the performance of photocatalytic hydrogen production.The results show that when the raw material ratio of organic semiconductor g-C3N4 to bismuth oxychloride is 1:2,under visible light irradiation(?> 400 nm),it has the best hydrogen production efficiency(36.6 ?mol·h-1·g-1),which is about 2.75 times that of g-C3N4(13.3 ?mol·h-1·g-1).At the same time,the combination of bismuth oxychloride and g-C3N4 expands the light absorption range of the composite material and promotes the red shift of the absorption band edge towards visible light.This heterojunction improves the photocatalytic performance.(3)Modified the surface of bismuth oxychloride with p-toluidine(a small organic molecule),Under simulated sunlight,the H2 generation rate of Bi OCl-PT(7.98 ?mol·h-1·g-1)is about 7.67 times that of Bi OCl(1.04 ?mol·h-1·g-1).Because the small organic molecules have the advantages of small steric hindrance and large contact area with the carrier compared to large organic molecules,therefore,the modification of small organic molecule on the surface of bismuth oxychloride have good efficiency of photocatalytic.