Preparation Of Gold Nanoparticles With Plant-mediated Method And The Study Of Their Photocatalytic Hydrogen Production Performance

The preparation of gold nanoparticles?GNPs?by plant-mediated method?also known as plant method?has attracted extensive attention from the scientific community due to its advantages of environmental-friendly and low cost.Although a large number of studies have proved its feasibility and great application potential,the universal preparation rules and mechanism of action composition are still unclear,and the regulation mechanism is not perfect.Grape wine residue?GWR?is a low-value plant resource,and its application in the preparation of GNPs can provide a simple and feasible way for its reuse.In addition,GNPs have widely application in the field of photocatalytic hydrogen production from water decomposition,but the use of GNPs prepared by plant method in photocatalytic hydrogen production has not been studied.First of all,this paper systematically studied the general law of plant method for preparing GNPs and focused on the action composition mechanism.Then,GWR was used for the preparation of GNPs and the regulation of GNPs was investigated.Based on the above research,GNPs prepared by GWR were applied to photocatalytic hydrogen production,the hydrogen production performance was optimized and the role of GWR and its prepared GNPs were explored.Firstly,16 kinds of plants were taken as research objects to obtain the preparation rules of plant method.The results showed that the color,water-soluble content and component content of different plant extracts had relatively consistent rules.GNPs were prepared from extracts of different plants and it was found that the concentration of extracts had a consistent effect on the preparation.In addition,the active functional groups in the preparation of GNPs from different plants are basically the same:the reducing groups are mainly O-H,and the protecting groups are mainly O-H and C=C.Statistical analysis and kinetic simulation results show that the preparation of GNPs with plant method is the result of synergistic effect of various components in the extract,of which polyphenols play the leading role.The order of reducing power of each component is polyphenols>flavonoids>sugars>proteins,and the order of protecting power is polyphenols>proteins>flavonoids>sugars.As the dominant components,polyphenols have strong reducing ability,and the protective ability shows a trend of first strong and then weak with the increase of concentration.Secondly,GWR was taken as the research object to prepare GNPs and explore the regulatory preparation method of GNPs.The optimal extraction method of GWR is as follows:after drying and grinding GWR into powder,extracting 60 g/L GWR with water for 6 h,0.9134 g of extract?GWRM?can be obtained.The content information of components in extract is as follows:sugars are the most,polyphenols and flavonoids are the second,and proteins are the least.GNPs with uniform particle size and good dispersibility can be prepared by using GWRM of 5 mg/mL,and the prepared GNPs are face-centered cubic crystals.The reductive components of GWRM in the preparation process are mainly phenols or polyhydroxy substances,while the protective components are mainly polyphenols and flavonoids.The experimental results show that GNPs with different morphologies and particle sizes can be prepared by changing GWRM concentration,HAuCl₄ concentration,temperature,acid-base environment and reaction vessel,which can realize the controlled preparation of GNPs.Finally,GNPs prepared by plant method was applied into eosin Y?EY?-sensitized photocatalytic hydrogen production system,good results were obtained.The best hydrogen production conditions are as follows:GNPs sol prepared by GWRM reaction of 3 mg/mL for 6 h was added to a TEOA solution containing 20 mg of EY at pH 9,the hydrogen amount can reach 358.12?mol at 5 h.The particle size and yield of GNPs are the most important factors that affect the hydrogen production effect,and GWRM also has a promoting effect.The results show that polyphenols and flavonoids are the main active components in the preparation process of GNPs,while polyphenols are the main active components of GWRM that can promote the hydrogen production system.