Controllable Fabrication of Nanostructured Cobalt-based Electrocatalysts for Oxygen Evolution Reaction

Author:Lv Feng Lei

Supervisor:wang zuo


Degree Year:2017





Electrochemical water splitting to produce hydrogen and conversion carbon dioxide into fuels and value-added chemicals are generally regarded as green technologies that can storage renewable energy(such as sunlight and wind)into chemical bond.The anode reaction for water splitting and carbon dioxide reduction,oxygen evolution reaction,providing protons and electrons for the cathode reactions,plays a key role in the above-mentioned green technologies.Involving four-electron-transfer process,oxygen evolution reaction need high overpotential to be driven.Noble metals based materials such as RuO2 and IrO2 are state-of-the-art oxygen evolution electrocatalysts.However,high price and low elemental abundance of Ir and Ru pose a serious limitation in their larger scale application in oxygen evolution.Due to good catalytic oxygen evolution performance and low price,cobalt based nanostructured materials are regarded as promising alternatives of noble metals Ru and Ir.Fabrication of cobalt based nanostructures by solution phase methods and revealing their structure-catalytic oxygen evolution performance are fundamentally important for the development in high performance electrocatalysts for oxygen evolution reaction.In this thesis,firstly,we synthesized cobalt hydroxides with controllable phases and indentified that the CoTd2+site shows better oxygen evolution performance than the CoOh2+site;secondly,we performed a surface protected reduction strategy to creating oxygen vacancies to ehance the conductivity of cobalt oxide;thirdly,a self-templating strategy was proposed to fabricate CoO-MoO2 nanocages to inprove the conductivity and enlarge the electrochemically active surface area of CoO;fourthly,we proposed coordination assisted eching route to incorporate Fe into CoO to enhance the adsorption of oxygen evolution intermediates(such as*OH and*OOH);finally,we performed a templating strategy to synthsizing iron decorated cobalt sulfide nanocages to modulate the electronic structure of cobalt and enlarge the electrochemically active surface area of cobalt sulfide.