Active-site and interface engineering of cathode materials for aqueous Zn–gas batteries

Aqueous rechargeable Zn–gas batteries are regarded as promising energy storage and conversion devices due to their high safety and inherent environmental friendliness.However,the energy efficiency and power density of Zn–gas batteries are restricted by the kinetically sluggish cathode reactions,such as oxygen evolution reaction(OER)during charging and oxygen reduction reaction(ORR)/carbon dioxide reduction reaction(CO_(2)RR)/nitrogen reduction reaction(NRR)/nitric oxide reduction reaction(NORR)during discharge.In this review,battery configurations and fundamental reactions in Zn–gas batteries are first introduced,including Zn–air,Zn-CO_(2),Zn-N_(2),and Zn-NO batteries.Afterward,recent advances in active site engineering for enhancing the intrinsic catalytic activities of cathode catalysts are summarized.Subsequently,the structure and surface regulation strategies of cathode materials for optimizing the three-phase interface and improving the performance of Zn–gas batteries are discussed.Finally,some personal perspectives for the future development of Zn–gas batteries are presented.

Non-noble-metal electrocatalysts for oxygen evolution reaction toward seawater splitting: A review

The direct electrolytic splitting of abundant seawater instead of scarce freshwater is an ideal strategy for producing clean and renewable hydrogen(H 2)fuels.The oxygen evolution reaction(OER)is a vital half-reaction that occurs during electrochemical seawater splitting.However,OER suffers from sluggish four-electron transfer kinetics and competitive chlorine evolution reactions in seawater.Noble metal-based catalysts such as IrO_(2) and RuO_(2) are considered to have state-of-the-art OER electrocatalytic activity,but the low reserves and high prices of these noble metals significantly limit their large-scale application.Recently,efforts have been made to explore efficient,robust,and anti-chlorine-corrosion non-noble-metal OER electrocatalysts for seawater splitting such as oxides,hydroxides,phosphides,nitrides,chalcogenides,alloys,and composites.An in-depth understanding of the fundamentals of seawater electrolysis and the design principle of electrode materials is important for promoting seawater-splitting technology.In this review,we first introduce fundamental reactions in seawater electrolytes.Subsequently,construction strategies for OER electrocatalysts for seawater splitting are introduced.Finally,present challenges and perspectives regarding non-noble-metal OER electrocatalysts for commercial H 2 production by seawater splitting are discussed.