水滑石纳米片用于生物质衍生物电催化氧化的研究进展

Recent progress on electrocatalytic oxidation of biomass-derived chemicals over layered double hydroxides nanosheets

电催化氧化(简称电氧化)生物质衍生物是一种环保高效的技术.与传统热催化相比,主要优势如下:(1)在电催化过程中,水系电解液可以通过解离/电离的方式产生氧源,因此无需使用高成本氧气;(2)常温常压下反应,避免高温高压对设备的苛刻要求;(3)控制施加的电位和改变电流可实现反应速率和产物选择性的调控;(4)易于使用多类型电化学方法和原位光谱联用方法监测反应过程.然而,现阶段电氧化反应的转化率和选择性仍有很大的提升空间,需要开发高效、高选择性、高稳定性的电催化剂,深入理解反应机理,为应用奠定技术支撑.本文首先综述了近年来报道的水滑石纳米片制备的常用剥离技术并进行对比,其次详细总结了水滑石纳米片用于呋喃类、苯甲醛、苯甲醇、甘油等生物质衍生物电氧化反应的机制与研究进展,最后展望了相关研究面临的挑战和前景,为水滑石纳米片用于电氧化研究提供理论指导和参考意义,促进生物质衍生物的应用.

With the increasing of global energy demand and environmental problems caused by the use of non-renewable fossil energy,people continuously develop the sustainable clean resource.Biomass is a renewable carbon-containing resource on Earth,composed of cellulose(30%–50%),hemicelluloses(15%–25%)and lignin(15%–30%),which is hydrolyzed to achieve a series of alcohol and aldehyde platform chemicals.The harmless disposal and clean transformation of biomassderived chemicals are essential means.The primary technology and method is converting biomass-derived chemicals into high value-added products.At present,the traditional thermochemical method is mainly used for biomass-derived chemicals conversion,which usually uses oxygen/hydrogen under high temperature,high pressure,and organic solvent.The precious metal-based catalysts are often used.Although the reaction obtains the high conversion and yield,the process is often accompanied by secondary pollution and high energy consumption.How to use clean methods to realize biomassderived chemicals upgrade has become the main challenge in the field of biomass green conversion at the present stage.In terms of the key problems of serious process pollution,low conversion and selectivity,and unclear mechanisms,biomassderived chemicals are used as raw materials and green methods are used to synthesize catalysts.Based on pollution control of the whole process,the electrocatalytic conversion technology with a clean process is used to study the efficient performance of biomass-derived chemicals conversion.Electrocatalytic oxidation of biomass energy derivatives is an efficient,green,and additive-free strategy.Compared with traditional thermal catalysis,the main advantages are as follows:(1)Dissociation and ionization in aqueous solution to produce oxygen sources,rather than using the high-cost O2for biomass-based oxidation conversion;(2)the normal temperature and pressure reaction conditions;(3)optimizing the rate of reaction and the selectivity of products by controlling applied potential,changing current density and designing highefficient catalysts;(4)multi-type electrochemical methods and in situ spectroscopy were used to monitor the reaction.However,conversion rate and selectivity cannot meet the current development needs.It is necessary to deeply understand the reaction mechanism and develop efficient and highly selective electrocatalysts to lay the foundation for large-scale applications.In this review,we first compared the common exfoliated methods for preparing layered double hydroxides nanosheets(N-LDHs),including soft chemical/liquid exfoliation,plasma-assisted exfoliation,mechanical exfoliation and other methods.Secondly,the latest progress for developing and utilizing N-LDHs in electrocatalytic energy conversion is introduced.The application prospect in the electrocatalytic oxidation reaction of furan,benzaldehyde,benzyl alcohol,glycerol and other platform chemicals is presented over N-LDHs nanosheets.In situ methods,mathematical computations,and sophisticated electrocatalyst studies are used to investigate the mechanism.Finally,this review looks forward to the challenges and prospects of related research.It provides theoretical guidance and reference significance for studying hydrotalcite nanosheets for electrocatalytic oxidation and promotes the application of biomass derivatives.