Water Splitting: From Electrode to Green Energy System

Abstract

HIGHLIGHTS • Bifunctional electrode and electrolytic cell configuration for electrochemical water splitting are reviewed. • The different green energy systems powered water splitting are summarized and discussed. • An outlook of future research prospects for the development of green energy system powered water splitting in practical application process is proposed. ABSTRACT Hydrogen (H 2) production is a latent feasibility of renewable clean energy. The industrial H 2 production is obtained from reforming of natural gas, which consumes a large amount of nonrenewable energy and simultaneously produces greenhouse gas carbon dioxide. Electrochemical water splitting is a promising approach for the H 2 production, which is sustainable and pollution-free. Therefore, developing efficient and economic technologies for electrochemical water splitting has been an important goal for researchers around the world. The utilization of green energy systems to reduce overall energy consumption is more important for H 2 production. Harvesting and converting energy from the environment by different green energy systems for water splitting can efficiently decrease the external power consumption. A variety of green energy systems for efficient producing H 2 , such as two-electrode electrolysis of water, water splitting driven by photoelectrode devices, solar cells, thermoelectric devices, triboelectric nanogenerator, pyroelectric device or electrochemical water-gas shift device, have been developed recently. In this review, some notable progress made in the different green energy cells for water splitting is discussed in detail. We hoped this review can guide people to pay more attention to the development of green energy system to generate pollution-free H 2 energy, which will realize the whole process of H 2 production with low cost, pollution-free and energy sustainability conversion.

Constructing RuCoOx/NC Nanosheets with Low Crystallinity within ZIF‐9 as Bifunctional Catalysts for Highly Efficient Overall Water Splitting

“…Hydrogen is a promising secondary energy in the construction of multiple energy supply system, due to the advantages of wide sources, high energy density, flexibility, and rich application scenarios [1,2] . The conversion of electric energy to hydrogen via electrocatalytic water splitting has become an important direction in the new energy technology revolution [3–5] . However, the high overpotential and sluggish kinetics of two half‐reactions [anode: oxygen evolution reaction (OER); cathode: hydrogen evolution reaction (HER)] reduce the energy efficiency of alkaline electrochemical water splitting [6–8] .…”

Electrocatalysis for the Oxygen Evolution Reaction in Acidic Media: Progress and Challenges

“…The nanostructures include zero-dimensional nanoclusters, nanoparticles, nanocages, and nanoframes [39]; one-dimensional nanotubes and nanowires [40]; two-dimensional nanosheets [41]; and three-dimensional nanowire Electrochemical water splitting involves two heterogeneous multi-step half-reactions, which are referred to as the cathodic hydrogen evolution reaction (HER) and the anodic oxygen evolution reaction (OER) [20,21]. Owing to the inherent energy barrier, the practical operating voltage of commercial water electrolyzers is higher than the theoretical 1.23 V (versus a reversible hydrogen electrode) under the standard conditions (298 K and 1 atm) [22,23]. For example, industrial electrolytic water generally maintains the external voltage at 1.8~2.0 V [16].…”

Engineering of nickel‐cobalt oxide nanostructures based on biomass material for high performance supercapacitor and catalytic water splitting

“…The splitting of water into its constituents, hydrogen, and oxygen can be considered as a good approach of energy production. 9 The main challenge in this research field is the selection of a material or catalyst to promote the process in a low cost and simple way.…”