Photoreforming Of Cellulose To H₂ By Pt-TiO₂ Photocatalyst

The large consumption of fossil fuels has caused environmental pollution.For the sustainable development of the mankind,the use of abundant and widely distributed biomass renewable energy to produce hydrogen can not only solve the disposal problem of biomass waste such as straw,but also generate hydrogen as a clean energy source.To achieve this goal,researchers have carried out a series of work.Among them,the photocatalytic degradation of cellulose to produce hydrogen based on chemical treatments is a hot research direction emerging in recent years.Its research focuses on the preparation of efficient photocatalysts and environmentally friendly pre-depolymerization of cellulose to make them produce the hydrogen better,thereby improving the hydrogen production efficiency.This article intends to explore the optimal method of platinum-supported titanium dioxide photocatalyst and the effect of pre-depolymerization of cellulose through the combination of inorganic salt an d pressure,and use its depolymerization product to assist photocatalytic decomposition of water to produce hydrogen.TiO₂ has the advantages of non-toxicity,low cost,high chemical stability and photocatalytic activity,and is widely used.However,titan ium dioxide alone cannot produce hydrogen through photocatalytic reaction,so it needs to support a cocatalyst.The four methods of photoreduction,thermal reduction,ball milling-dipping and sodium borohydride reduction were used to support platinum on titanium dioxide,and the physical and chemical characterization s of them was carried out from multiple angles to study the effect of different loading methods on the shape of the promoter.The appearance,size,valence state,content and light absorption properties of the catalyst affect the hydrogen production performance of the catalyst.Experiments show that the platinum-supported titanium dioxide（Pt-TiO₂）photocatalyst prepared by the photoreduction method has the best hydrogen production effect.The factors affecting the depolymerization of cellulose under pressure by inorganic salts are explored.Under certain pressure conditions,lithium chloride or lithium bromide containing a certain amount of lithium ions is used as an intercalant,which can effectively destroy the intermolecular and intramolecular hydrogen of cellulose.The bond and its crystalline structure break it into short-chain cellulose and glucose molecules.The hydrogen production and sugar production of cellulose after photocatalyti c pre-depolymerization,as well as the combination of all material characterization experiments show that the pressure-assisted lithium ion intercalation method can depolymerize cellulose,and inorganic salts and pressure are indispensable.The average par ticle size of cellulose is reduced,the crystallinity is greatly reduced,and the hydrogen bond structure is effectively destroyed.Using the optimally prepared Pt-TiO₂ to depolymerize the cellulose product by pressing its inorganic salt,the photocatalyti c water splitting and hydrogen production were studied,and the effects of different experimental factors on the hydrogen production efficiency were investigated.Experimental results show that glucose molecules produced by cellulose depolymerization can g reatly improve the efficiency of hydrogen production,and inorganic salt molecules can be recycled and reused.In addition,the inorganic salt pressurization method can also be used to depolymerize a variety of biomass materials such as rice,wheat,etc.The depolymerization products can improve the efficiency of photocatalytic hydrogen production and realize the development and utilization of biomass resources.