Kwun Nam Hui
Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Macau
E-mail: bizhui@um.edu.mo

Highly effective electrocatalysts are significant for the development of sustainable and renewable energy storage and conversion for net-zero carbon society. To date, designing and synthesizing low-cost, highly efficient, and stable electrocatalysts for practical applications in sustainable energy storage and conversion has been an imperative yet challenging subject. Numerous efforts and progress have been dedicated to exploring efficient non-noble catalysts based on earth-abundant elements, such as transition metal phosphates, oxides, hydroxides, chalcogenides, carbides, and phosphides, among others. Unfortunately, most transition metal-based catalysts have inadequate intrinsic activities compared with noble metal materials because of their relatively low conductivity and unsuitable electron structure.

In this talk, several strategies, including morphology control, heterostructure architecture, and defect engineering, will be discussed to regulate the intrinsic electronic structures of transition-metal-based catalysts to achieve high electron conductivity of the electrocatalysts and reduce binding energies of the reaction intermediates towards rate-determining steps of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Experimental analyses and theoretical calculations reveal that the electronic structure of electrocatalysts can be efficiently modulated by introducing dopants as defects and incorporating metal nanoparticles on substrate-support, which synergistically improves oxygen intermediates adsorption/desorption, enhancing the ORR and OER performance. Finally, the potential applications of electrocatalysts in metal-air batteries will be discussed.