Fabrication Of AgNi And Ag/C Materials And Their Performance Study Of Electrocatalytic Reduction Of Carbon Dioxide

Carbon dioxide（CO₂）, is a thermodynamically stabile chemistry with the element C at the highest valence state. In recent years, due to excessive human producing and living activities, the concentration of CO₂ in the atmosphere has been rising at an unprecedented rate, and the temperature is rising as well. As a result, the melting of glaciers, rising sea levels and extreme weather make people realize that to reduce the concentration of CO₂ is extremely urgent. Transforming CO₂ by means of electrochemical reduction is no doubt of great theoretical and practical significance, it can not only reduce the concentration of CO₂ in the atmosphere, but also store extra solar energy, wind energy, nuclear energy in the carbon-containing chemicals.In this work, we fabricated AgNi alloy and Ag/C, and characterized them by means of XRD, SEM, TEM and so on. Besides, we combined three electrode system with gas chromatography to see how the synthesis and testing conditions affect the CO₂ catalytic ability in aqueous electrolyte. In addition,we talked about the possibility of AgNi alloy and Ag/C we made to be syngas catalyst.In this work, we find that use KHCO₃ as the electrolyte can achieve higher H2 and CO yields and Fafadic efficiency. Furthermore, we find that improve the concerntration of KHCO₃ can also achieve the same goal, and can get the more reduced production CH4. Choice of basis means a lot in our research. If we choose Al as the basis, we can only get H2 and CO when the basis is Ag, but if Cu is the basis, we can get both H2 and CO at a large amount and suitable ration as syngas. Reducing the deposition potential will make the AgNi layer rough and a higher Ni concerntion. Meanwhile, we can improve the onset potential, yields and Fafadic efficiency of H2 and CO. When the deposition potential is-0.85 V, the yields of H2 and CO can reach 1000 ppm and even close to 2000 ppm.When we are fabricating Ag/C, it will be better to choose EG as the reductant as the product Ag/C may be pure, and therefore a better catalytic performance than there is Ag2 S act as impurity. When MWCNT is the supporter, extenting the reaction time will enlarge the particle size and improve the catalytic ability. Carbon black is a better supporter than MWCNT and graphene oxide, when the potential is in range of-0.8V^-1.2V, the F（CO） be larger than 50%. The best ratio of AgNO₃ and the anchoring agent Cysteamine is 4:1, less Cysteamine means smaller Ag particles and more Cysteamine results in isolated Ag with Carbon black,and both of them wosen the catalytic ability. The content of Ag in Ag/C can be tuned by controling the ratio of AgNO₃ and Carbon black, either too little or too much Ag will wosen the catalytic ability and the best ratio is 1:1. Heating the synthesized Ag/C can greatly improve the catalytic ability, to get a CO current density of 3 mA/cm^-2, we neet a potential of-0.75 V, which is 0.5V higher than that of Ag foil, and is better-performanced than the reported ones. The yields of H2 and CO can be up to 700 ppm, make it a good candidate for CO₂ electroreduction.