| At present,the total amount of fossil energy in the world is becoming more and more short,and the burning of fossil fuels such as coal aggravates the environmental pollution and causes a series of problems such as global warming.As we know,hydrogen energy has high calorific value,superior performance,innocuity and environmental protection,and can be used as a clean energy source instead of traditional fossil energy.At the same time,agricultural wastes such as corn stalks are also renewable resources that can be widely used.With extensive research by researchers,it is found that agricultural wastes such as biomass corn stalks can be used as raw materials for hydrogen production,and gasification is one of the commonly used methods for hydrogen production from biomass,but these methods have many problems such as high energy consumption and high cost.However,photocatalytic reforming of biomass to produce hydrogen can give full play to its advantages and store unstable solar energy in the form of chemical energy.In this paper,the photocatalytic hydrogen production activity of composite catalyst suitable for sacrificial corn stalk,various factors that may affect the hydrogen production efficiency,and the influence characteristics of pretreatment of sacrificial corn stalk with ultrasonic and alkali liquor on photocatalytic hydrogen production efficiency were studied.Firstly,Cu2O/TiO2 composite catalyst was prepared by chemical deposition method,and the direct influence of different proportion of Cu2O in Cu2O/TiO2 on hydrogen production efficiency was studied.According to the experimental results,the activity of the catalyst for hydrogen production is better when the catalyst is added into the photocatalytic system with corn straw as sacrificial agent.When Cu2O content is 1%,Cu2O/TiO2 with concentration of 1×10-3 g/m L and corn straw granules with concentration of 0.3×10-3 g/m L are added,the highest H2 output is 33.71μmol.The factors affecting the efficiency of hydrogen production by photocatalysis with corn straw as sacrificial agent were studied.The system composed of Cu2O/TiO2 with concentration of3×10-3 g/m L,corn straw particles with concentration of 0.5×10-3 g/m L and 100 m L deionized water with p H=11 was irradiated by ultraviolet light,and hydrogen production was 142.41μmol in 4 hours,which was 10 times higher than that by photocatalytic decomposition of pure water.Secondly,under the condition of xenon lamp irradiation,in the reaction system with Cu2O/TiO2 as catalyst,and adding corn stalks treated by alkali liquor,the reaction can be effectively promoted and the rate of hydrogen production by photocatalytic hydrolysis can be obviously improved.The effects of Na OH concentration,pretreatment time and pretreatment temperature on photocatalytic hydrogen production were studied by single factor experiment and orthogonal experiment.The experimental results show that when Na OH concentration is 2%,pretreatment temperature is 80℃,and pretreatment duration is 1 h,the hydrogen production of corn straw by photocatalytic reforming can reach 106.67μmol.At last,the structure of corn straw changed after ultrasonic treatment,which can improve the rate of hydrogen production by photocatalytic decomposition of pure water.After testing and analyzing corn straw by means of characterization technology,it was found that ultrasonic treatment would change the structure and components of corn straw,and then affect the photocatalytic hydrogen production reaction.According to the experimental results,under the condition that the water temperature in the ultrasonic cleaner is 60℃,the hydrogen yield of the photocatalytic reforming corn straw can reach 52.58μmol after continuous treatment for 2 hours.According to the conclusions of the above experiments,we can study the influence of pretreated corn stalks on hydrogen production efficiency and reaction mechanism in the photocatalytic reaction process,and have certain reference significance for the utilization of natural biomass and the preparation of hydrogen energy. |
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