Polybipyridine Cobalt Complexes Catalyze Proton Hydrogen Production

The rapidly increasing consumption of fossil energy during the development of modern society leads to the more and more serious greenhouse effect of the globe.At the same time,the non-renewability of fossil fuel forces human beings to find alternative energy sources.In this context,hydrogen has caught great attention as a potential alternative fuel whose use could result in a closed carbon-neutral energy production system.One of the keys for successfully generating hydrogen from water is an efficient and stable hydrogen evolution reaction(HER)catalyst.While the outstanding efficiency of platinum as a HER catalyst is well-known,the scarcity of this noble metal seriously limits its widespread application.Cobalt complexes,even though not directly related to the transition metal sites of hydrogenases,have been reported in the recent years as active catalysts for hydrogen evolution.Some examples with unique structures displayed excellent activity and intriguing catalytic mechanism.The conjugation of polypyridine ligand helps to stabilize a low-valent cobalt center and favors ligand-centered reduction at a relatively positive potential.In addition,easily modified polypyridine ligands makes a systematic structure-activity study possible.The main content of this thesis is design,synthesize,and characterization of two series of novel polypyridyl cobalt complexes,and investigation of their electrocatalytic HER performance and mechanism,including the following two chapters:(1)Design and synthesis of four novel cobalt complexes with 1,10-phenanthroline based lypyridine on ligand.These complexes have been characterized using classic spectroscopic methods.Electrocatalytic HER performance and mechanism of these complexes have been investigated.(2)Design,synthesis,and fully characterization of novel polypyridyl-type cobalt complexes with 8-(1″,10″-phenanthrol-2″-yl)-2-(pyrid-2′-yl)quinoline(ppq)and its derivatives as ligands.Electrocatalytic HER performance and mechanism of these complexes have been investigated.