Research And Application Of Sunlight Driven Thermal Catalytic Water Gas Shift Reaction For Hydrogen Production And Toluene Combustion

In recent years,rapid economic development and the burning of large amounts of fossil fuels have increased the environmental load and made it urgent to solve environmental problems.The development of green energy sources instead of fossil fuels and the degradation of environmental pollution have become two of the mainstream ways to solve environmental problems.Solar energy is a green,sustainable energy source.As 80%of human activities are carried out through catalytic reactions,sunlight-driven catalysis is a viable and economical way to solve environmental problems.Solar-driven catalysis mainly includes photocatalysis,photovoltaic catalysis and photothermal catalysis,however,photocatalysis and photovoltaic catalysis are too inefficient,and photothermal catalysis requires a high-density light source to drive or assist with heating,making it unsuitable for large-scale applications.Therefore,it is very meaningful to realise catalysis under sunlight.Our group has creatively proposed the concept of light-driven thermal catalysis and developed a novel photothermal device that converts sunlight fully into thermal energy and heats the device temperature to the required temperature for catalysis.Based on this,this paper develops a highly efficient catalyst combined with a novel photothermal device for sunlight-driven thermal catalysis,and selects hydrogen,which is expected to replace fossil fuels,and toluene,a typical volatile organic compound in environmental pollution,to explore the application of the novel photothermal system in the field of hydrogen production and degradation of toluene.The main research of this paper is as follows.1.The properties of spectrally selective absorption are revealed by finding that a specific thickness of chromium film can absorb solar light efficiently and infrared light inefficiently.A novel photothermal device based on chromium film was constructed to efficiently absorb sunlight,convert sunlight into thermal energy and reduce thermal radiation through spectral selection to achieve thermal energy localisation.Under 1 k W m^-2intensity sunlight irradiation,the novel photothermal device can heat the catalyst to 299°C.2.The 2D CuZnAl nanosheets were prepared in large quantities by boric acid-assisted co-precipitation for the study of hydrogen production from water gas reaction.Further,the 2D CuZnAl catalyst combined with a novel photothermal device can be heated to 299°C under 1k W m^-2intensity sunlight irradiation,and the hydrogen production rate from water gas reaction reached 192.33 mmol g^-1h^-1,which is 402 times higher than that recorded for water gas conversion reaction driven by 1 k W m^-2intensity sunlight irradiation.In addition,the system was scaled up to industrial scale with an irradiated area of 4.2 m²to produce 6.60 m³of hydrogen from the water-gas reaction driven by outdoor sunlight alone during the spring daytime,and achieved zero CO₂emissions with the aid of greenhouse agriculture.3.The Cu-CeO₂ catalysts were prepared by hydrothermal method for the catalytic combustion of toluene.1000 ppm of toluene was completely combusted by Cu-CeO₂catalysts at 245°C with high catalytic activity and no secondary pollution.More importantly,the Cu-CeO₂catalyst combined with a novel photothermal device reached a temperature of299°C under 1 k W m^-2intensity sunlight irradiation and the yield of the toluene combustion reaction was 21.93 mmol g^-1h^-1.4.The Cu-CeO₂ microsphere catalysts were synthesized by PVP-assisted spray drying method for the study of catalytic combustion of toluene.The drawbacks such as the inability to produce the Cu-CeO₂catalysts prepared by hydrothermal method on a large scale were solved.Further,Cu-CeO₂microspheres combined with a novel photothermal device reached a temperature of 299°C under 1 k W m^-2intensity sunlight irradiation,and the yield of the toluene combustion reaction was 59.82 mmol g^-1h^-1,which was 2.8 times that of the Cu-CeO₂catalyst and 150 times that recorded for sunlight-driven toluene combustion.An industrial demonstration of this new system was also carried out,which was able to completely treat22.2 m³h^-1of toluene at concentrations of 1 to 10,000 ppm under outdoor sunlight irradiation of 1 m²in winter daylight,showing potential for industrial applications.