电解水制氢技术及大电流析氧反应研究与展望

Research and perspectives on electrocatalytic water splitting and large current density oxygen evolution reaction

当今时代对可持续能源的迫切需求推动了可再生能源技术的不断改进,其中氢能因其清洁环保且能量密度高而受到了科研人员广泛关注.电解水制氢作为一种绿色环保的制氢方式,其阳极析氧反应(OER)的高能耗限制了电解水制氢技术的广泛应用.近年来,高性能的OER催化剂的研究得到了长足发展,但催化剂的测试范围小,且很少能够连续工作数百小时,远远不能满足实际应用的需求.为了更好的适用于工业应用,OER催化剂需要满足更苛刻的测试环境,如在低过电位下提供大电流密度、在强气体排放过程中维持稳定性和耐久性,因此开发在大电流密度下的高活性OER催化剂是当前工作的重中之重.结合大电流OER催化剂的研究进展,本文首先提出氢能是目前最有前途的能源之一,并调研了大电流密度下电催化剂的研究现状.其次通过对OER机理进行分析,发现采取元素掺杂、界面工程、缺陷工程和形貌工程等措施可以提升催化剂在大电流密度下的活性.最后,对大电流析氧领域在工业发展中现阶段存在的挑战及未来发展方向进行了展望.

With the consumption of fossil fuels and the deterioration of the ecological environment,the need for developing new,efficient,and sustainable sources of clean energy is urgent.The importance of“green hydrogen”in electrolytic water splitting has attracted worldwide attention not only from the scientific community but also from governments and industries.Hydrogen energy is considered an ideal alternative to fossil fuels because of its high energy density,environmental friendliness,and low pollution level.Hydrogen production from renewable energy sources using the electrolysis of water is the lowest carbon emission process of the many current hydrogen source options.The electrolytic water reaction is subdivided into two half-reactions,namely,the hydrogen evolution reaction(HER)at the cathode and the oxygen evolution reaction(OER)at the anode.The HER is a relatively simple two-electron reaction.Compared to the HER at the cathode,the OER at the anode is a four-electron transfer process with slower kinetics and higher energy barriers.It is the decisive step in the electrolytic water reaction,receiving considerable attention from scholars.Recently,considerable developments in the research of high-performance electrolytic water catalysts have been reported as successful;however,the catalysts have been tested on a very small scale,usually under laboratory conditions,and can rarely operate continuously for hundreds of hours,far from meeting the needs of practical applications.Industrial-level electrocatalytic hydrogen production requires catalysts that are highly active,cost-effective,and stable at high current densities;thus,a great deal of work has explored efficient and highly durable active electrocatalysts to overcome the kinetic barriers that inhibit the reaction,particularly for the complex four-electron reaction of the OER.In summary,catalysts for oxygen precipitation reactions at high current densities will be the focus of future research.This paper reviews the current status of hydrogen energy development and various hydrogen production methods at home and abroad,focusing on an analysis of electrolytic water hydrogen production technology and proposing the requirements under large-scale industrial applications.Studying the OER mechanism has revealed that the activity of catalysts at high current densities can be enhanced by the following strategies:heteroatom doping,defect engineering,interface engineering,in situ self-growth,etc.Finally,the challenges in the field of high-current oxygen analysis at this stage of industrial development and the future direction of development are presented.