钯基催化剂电催化氢解处理氯代有机物的研究进展

Progress in Electrocatalytic Hydrogenolysis of Chlorinated Organic Compounds on Palladium-Based Catalysts

氯代有机物(COPs)是一类重要的化工生产原料和中间体,但其高持久性、高生物累积性、致癌性及遗传毒性将对生态环境和人体健康造成巨大危害.开发消除COPs毒性的新型技术,实现人与自然和谐共生,成为国际学术界和工业界共同关注的焦点.电催化氢解技术(ECH)因具有高反应活性、结构简单、二次污染风险小等优势而备受青睐.本文系统综述了钯(Pd)基催化剂上的ECH反应机制,探究强还原性氢自由基(H^(*))的定量分析方法,揭示脱氯反应与析氢副反应间的竞争关系.通过分析H^(*)产量、污染物脱附、电场等因素对脱氯速率的影响规律,建立晶面与效能间构效关系,识别不同反应条件下制约ECH速率的因素.聚焦阴极催化活性低、易受脱氯产物毒化的关键问题,通过暴露Pd活性中心位点、强化水裂解、调控电子效应和配体效应及几何效应等策略增强催化剂产H^(*)量和抗毒化性能.开展ECH脱氯反应路径识别、脱氯性能影响因素探讨以及生物安全性评价,并基于当前存在的关键科学问题,展望ECH技术的发展趋势,为设计和发展实用型环境催化新技术和新型催化材料指明方向.

Chlorinated organic compounds(COPs)are important chemical raw materials and intermediates with wide applications in industry and agriculture.However,due to their high persistence,strong bioaccumulation,carcinogenicity and genotoxicity,they pose a threat to the ecological environment and human health.In the pursuit of harmonious coexistence of human and nature,efficient and green technology that can detoxify the COPs is therefore urgently needed.Electrocatalytic hydrogenolysis(ECH)is a competitive alternative due to its extremely high reactivity,mild reaction conditions and little secondary pollution.In this review,we systematically summarize the progress in the development of ECH technology for detoxication of the COPs on representative palladium-based catalysts.The initial research on ECH primarily focused on the mechanism as well as method to quantify the in-situ produced atomic hydrogen free radicals(H^(*))on catalyst.These free radicals are highly reductive to cleave the C—Cl bonds.Subsequently,extensive efforts were devoted to revealing the competitive relationship between ECH and side hydrogen evolution reaction.Moreover,by comparing the impacts of H^(*)generation,product desorption and electric field on the ECH kinetics,the Pd surface structure-ECH activity relationship was established,contributing to the identification of the rate-determining step under different reaction conditions.Aiming at enhancing the ECH activity,several efficient strategies were then developed to increase the H^(*)production and enhance its anti-poisoning performance via the electronic,ligand and geometric effect.Recently,the research focused more on the ECH pathway,the effects of environmental conditions on ECH and the biological safety of the water before and after ECH treatment.On basis of the presented progress,we finally prospect the future research priorities and directions for designing and developing new practical environmental catalysis technologies and catalytic materials.