Abstract

　　In most water electrolysis technologies, the proton source is from the water. Because of use of highly active precious metal catalysts Pt and Ir, there is a strict requirement for quality of the water feedstock, e.g. ultrapure DI water. Increasing demand for H₂ will significantly exacerbate present scarcity of limited freshwater. Seawater is an (almost) unlimited resource and a natural feedstock for H2. This is practical for geographical regions with long coastlines and abundant sunlight, but freshwater is actually scarce. Because of salt (Na⁺, Cl⁻) and minor ions/cations (SO₄²⁻, CO₃²⁻, Mg²⁺ and Ca²⁺), it is necessary to treat seawater to a level of purity for conventional electrolyser including desalination and deionization. Here we identified two representative reactions, namely, 1) direct seawater splitting to H₂ at cathode (in both PEM and alkaline electrolyser modes) and, 2) natural chloride promoted C₂H₄ electrooxidation to 2-chloroethanol at anode, to demonstrate the concept of direct seawater-based electrocatalysis. The newly developed process – using natural seawater instead of purified water as feedstock – enables new concepts in electrocatalysis fundamentals, electrode materials design, and electrolyser technology.

Biography

　　Yao Zheng received his PhD degree in 2014 with Prof. Shizhang Qiao from University of Queensland. Currently, he is an Associate Professor in the School of Chemical Engineering in the University of Adelaide. Dr Zheng’s research is focused on the electrocatalysis principle development and electrocatalyst design for energy conversion application, which includes reaction mechanism understanding, nanomaterials synthesis, in-situ spectroscopic measurements. He has worked for the past 15 years on developing advanced electrocatalysts for a series of energy conversion processes like oxygen-and hydrogen-involving reactions, CO₂ reduction reactions, and other electrocatalytic-refinery processes. He has published >150 research papers, which have attracted > 37,000 citations, with an h-index of 76. He was Clarivate Analytics Highly Cited Researcher (in the field of Chemistry) in 2019–22.