For example, for the platinum rhodium alloy catalyst in ammoxidation, the effective material is the content of platinum and rhodium. For the catalytic oxidation of sulfur dioxide, vanadium pentoxide is the effective material, but the content is only more than 10%.

In recent years, with the rapid development of industry and the rapid increase of population, volatile organic compounds (VOCs) emissions into the air have increased dramatically, which has become the main cause of air pollution, seriously endangering human health and restricting the sustainable development of social economy. It is urgent to seek reasonable and effective control technology to solve VOCs Pollution. Catalytic combustion is a kind of treatment technology to realize high efficiency combustion of VOCs. Because of its advantages of low ignition temperature, high treatment efficiency and no secondary pollution, it shows great competitiveness in the process of VOCs purification. The core problem of catalytic combustion technology lies in the design and preparation of highly efficient and stable catalysts. Noble metal catalysts (such as Pt, PD and Au) have high catalytic activity and selectivity. However, due to the scarcity of resources and high price, these catalysts are usually supported on the support, and used as a negative catalyst for VOCs catalytic combustion. On the one hand, it can improve the dispersion of precious metals, reduce the amount of precious metals, and reduce the cost of catalysts. On the other hand, it can play a synergistic role between precious metals and supports, and improve the catalytic performance of catalysts.1Pt catalystPt catalyst has a high catalytic activity for VOCs combustion. As a supported catalyst, its activity is often affected by many factors, such as the nature of the support, particle size and Pt loading. Due to the specific surface area, pore structure, pH value and hydrophobicity of the support, the dispersion of active components, the adsorption of reactant molecules and the interaction between metal and support are usually greatly affected, which greatly determines the catalytic activity of the supported Pt catalyst; Therefore, different supports will lead to different VOCs catalytic activity of supported Pt catalyst. In many carriers, γ - Al2O3 has been widely studied and applied because of its large specific surface area, high stability and low cost. Using commercial γ - Al2O3 as the support, ordo et al. Prepared Pt / γ - Al2O3 Catalyst by impregnation method, which was used in the catalytic combustion of benzene, toluene and n-hexane respectively. It was found that the Pt / γ - Al2O3 catalyst had good catalytic combustion activity, and its complete oxidation could be realized under 200 ℃. The results show that the pH value of the support plays an important role in improving the performance of the supported Pt catalyst. Yazawa et al. Found that the supported Pt catalysts prepared with Al2O3, MgO, La2O3, ZrO2, SiO2-Al2O3 and SO42 -- ZrO2 with different pH have obvious differences in propane catalytic activity. The stronger the acid is, the better the catalyst activity is. This is due to the strong oxidation resistance of Pt on acid support, which makes Pt / SO42 -- ZrO2 Catalyst have the most excellent oxidation resistance At 227 ℃, the conversion of propane is over 80%. Compared with the conventional Al2O3 supported Pt catalyst, the supported Pt catalyst (such as Pt / H-ZSM-5 and Pt / mcm-14, etc.) prepared with molecular sieve as the support has better dispersion of Pt metal, and the porous characteristics of molecular sieve can effectively prevent the generation of by-products and the occurrence of carbon deposition, thus showing better aromatics catalytic combustion activity. As the water vapor generated by VOCs catalytic combustion is easy to agglomerate in the catalyst channel, it is easy to passivate the catalyst. Therefore, the hydrophobicity of the support plays an important role in maintaining high catalytic activity and good stability of the supported catalyst. It was found that supported Pt catalysts prepared by porous polystyrene (SDB), activated carbon and carbon aerogels as carriers exhibited excellent catalytic activity for Toluene Combustion. Among them, Pt / SDB catalyst can realize the complete oxidation of toluene under the reaction temperature of 150 ℃, which shows that porous hydrophobic support can not only inhibit the generation of by-products and the occurrence of carbon deposition, but also effectively remove the water vapor on the surface of catalyst, thus greatly improving the performance of catalyst.1Pt catalystPt catalyst has a high catalytic activity for VOCs combustion. As a supported catalyst, its activity is often affected by many factors, such as the nature of the support, particle size and Pt loading. Due to the specific surface area, pore structure, pH value and hydrophobicity of the support, the dispersion of active components, the adsorption of reactant molecules and the interaction between metal and support are usually greatly affected, which greatly determines the catalytic activity of the supported Pt catalyst; Therefore, different supports will lead to different VOCs catalytic activity of supported Pt catalyst. In many carriers, γ - Al2O3 has been widely studied and applied because of its large specific surface area, high stability and low cost. Using commercial γ - Al2O3 as the support, ordo et al. Prepared Pt / γ - Al2O3 Catalyst by impregnation method, which was used in the catalytic combustion of benzene, toluene and n-hexane respectively. It was found that the Pt / γ - Al2O3 catalyst had good catalytic combustion activity, and its complete oxidation could be realized under 200 ℃. The results show that the pH value of the support plays an important role in improving the performance of the supported Pt catalyst. Yazawa et al. Found that the supported Pt catalysts prepared with Al2O3, MgO, La2O3, ZrO2, SiO2-Al2O3 and SO42 -- ZrO2 with different pH have obvious differences in propane catalytic activity. The stronger the acid is, the better the catalyst activity is. This is due to the strong oxidation resistance of Pt on acid support, which makes Pt / SO42 -- ZrO2 Catalyst have the most excellent oxidation resistance At 227 ℃, the conversion of propane is over 80%. Compared with the conventional Al2O3 supported Pt catalyst, the supported Pt catalyst (such as Pt / H-ZSM-5 and Pt / mcm-14, etc.) prepared with molecular sieve as the support has better dispersion of Pt metal, and the porous characteristics of molecular sieve can effectively prevent the generation of by-products and the occurrence of carbon deposition, thus showing better aromatics catalytic combustion activity. As the water vapor generated by VOCs catalytic combustion is easy to agglomerate in the catalyst channel, it is easy to passivate the catalyst. Therefore, the hydrophobicity of the support plays an important role in maintaining high catalytic activity and good stability of the supported catalyst. It was found that supported Pt catalysts prepared by porous polystyrene (SDB), activated carbon and carbon aerogels as carriers exhibited excellent catalytic activity for Toluene Combustion. Among them, Pt / SDB catalyst can realize the complete oxidation of toluene under the reaction temperature of 150 ℃, which shows that porous hydrophobic support can not only inhibit the generation of by-products and the occurrence of carbon deposition, but also effectively remove the water vapor on the surface of catalyst, thus greatly improving the performance of catalyst.

The ratio of the number of atoms of the active component exposed on the catalyst surface to the total number of atoms in the catalyst.There are physical and chemical methods for the determination of dispersion:The physical method is to directly observe the particle size (through the electron microscope or XRD), and calculate the dispersion of metal through the formula.The first mock exam is to adsorb a model molecule selectively on the surface of precious metal (the premise is to accurately understand its stoichiometry). By calculating the adsorbed gas molecules, the number of atoms on the surface of the metal can be calculated. It is common to have H2 and CO molecules as model gases.

In order to promote the communication among all departments of the company, cultivate team spirit, break through self limit and further enhance the cohesion of the company, the personnel department of the company organized the "family happiness" outdoor collective activity in Cixi Shangri resort in early May 2017. This activity calls for "all members to participate and family members to accompany".After all the staff gathered in the parking lot of Cixi Shangri manor, they were divided into four groups of ABCD to carry out activities under the guidance of the coach. This activity is mainly divided into five links: Hedu Tongxin bridge, CS competition, killing game, crawl relay, brave jump bridge. The whole process adopts group point ranking system, which includes cooperation and competition, personal experience and team test.Concentric crossing:The iron rope is linked with one heart, and can only cross with one heart. The first wave of bridge crossing starts after safety measures are taken. Trembling and walking on thin ice should be a reflection of the mood of the first wave of bridge crossing people when they boarded the bridge. However, with the their fingers clasped, their steps were consistent and decisive. The cable was shaking violently, especially in the middle of the bridge!The first time they cross the bridge, they have no experience. Everyone cheers for them, and other tourists stop to watch and take photos. Tension stops, arms work, fingers clasp, support each other, trust each other - soon they are stable, continue to move forward, and pass through without danger! After that, all other bridge crossing combinations also cross the bridge in one time.Offensive and defensive confrontation:If problems are like defenders, how can we attack and overcome them? If the same industry is like the aggressor, how can they hold their position? CS offensive and defensive competition, in addition to entertainment, may also have this interpretation. In the three games, each group is brave and resourceful. They attack from the front, snipe from high places, break through from the side, encircle the rear, lure and support, etc. Although the battlefield is small, there are many tactics. In the summer sun, we try our best to enjoy ourselves.Kill game:Killers, police, doctors, civilians, who will be killed this night? Who killed again? Did you catch the killer At leisure after dinner, everyone gathered at the same table and played a game of killing people. Role switching, camouflage and justification, logical reasoning, and rest are also enjoyable.Crawl relay:Hanging a net on a hundred meter slope, crawling like a wave. Each group needs to climb the relay quickly, during which some members climb the tree like apes; some girls are not strong enough, but still insist on climbing the highest; some of them climb to the highest and then climb the peak again, with tired hands and feet, but happy.Brave leap to break the bridge:Fear of heights? Ten meters is not high. The bridge is cut across, everyone pays attention to it, whether they dare to make a leap or not, the biggest challenge is themselves. Whether it's hesitation or decisiveness, it's the hero who goes up! Just like a schoolmate, he is young and prosperous. The combination of iron rope, attack and defense, killing and heart attack, climbing relay, breaking bridge and jumping bravely are all heroes! So far, this outdoor activity has come to a successful end. Everyone drives back to wisdom valley. In addition to the ranking of points, we have also prepared small prizes for everyone. The activity focuses on participation and happiness.