Reconstruction‐Determined Alkaline Water Electrolysis at Industrial Temperatures

Abstract

Water-electrolysis technology can realize zero CO 2 emission and acquire large-scale hydrogen with high purity (>99.9%), and thus potentially serves as a key component in future sustainable energy systems. [1,2] However, this technology accounts for only 4% of current hydrogen production, which is mainly attributed to its higher cost in comparison with other methods such as the conversion of natural fossil fuels. [3] For commercial water electrolysis systems, the existing key problems mainly focus on the use of efficient but exorbitant iridium, ruthenium or platinum catalysts, or economically practical nickel meshes and stainless steel with the unsatisfying activity. [4] Exploring highly active and costeffective catalysts with good durability is imperative but challenging. Though important breakthroughs have been made recently in investigating high-efficiency first-row transition metal catalysts for oxygen and hydrogen evolution reactions (OER and HER), [5-9] a certain gap still exists between the test condition (almost at room temperature, Table S1, Supporting Information) and the industrial one (at 50-80 °C). Therefore, it is essential to evaluate the catalytic performance and compatibility of catalysts under such harsh operating condition for further practical applications. Rational design of HER and OER catalysts which can be well operated at industrial temperatures is highly desirable for practical alkaline water electrolysis (AWE) application. Our reported MoO 2-Ni arrays exhibited a Pt-like HER activity at 25.0 °C, and the convenient synthesis route was beneficial to its mass production. [10] Such a catalyst serves as a potential candidate because its heterogeneous components may avoid agglomeration under high-temperature catalytic conditions. For anodic OER, some researchers recently evaluated the catalytic performance at 80 °C, such as NiFe-LDH [11] in alkali or CoFePbO x [12] in acid, however with only ≈20 h operation. Our recent works have focused on the reconstruction chemistry of catalysts, demonstrating that the deeply/completely reconstructed (denoted as DR/CR) catalysts are a potential choice. The reported DR-NiOOH was operated well with activity decay of 0.35 mV h −1 in 40 h tested at 52.8 °C. [13] In addition, the DR catalysts with abundant active species can realize high component utilization and thus high-mass-activity catalysis. Nevertheless, the lithiation Evaluating the alkaline water electrolysis (AWE) at 50-80 °C required in industry can veritably promote practical applications. Here, the thermally induced complete reconstruction (TICR) of molybdate oxygen evolution reaction (OER) pre-catalysts at 51.9 °C and its fundamental mechanism are uncovered. The dynamic reconstruction processes, the real active species, and stereoscopic structural characteristics are identified by in situ low-/ high-temperature Raman, ex situ microscopy, and electron tomography. The completely reconstructed (CR) catalyst (denoted as cat.-51.9) is interconnected by thermodynamically stable (oxy)hydroxide nanopartic...

Evolving Highly Active Oxidic Iron(III) Phase from Corrosion of Intermetallic Iron Silicide to Master Efficient Electrocatalytic Water Oxidation and Selective Oxygenation of 5‐Hydroxymethylfurfural

“…After conclusively characterizing our system, we decided to apply it under industrially relevant OER conditions which include elevated temperatures and large current densities. [ 34–36 ] First, we performed LSVs at different temperatures up to 65 °C and could observe a significant enhancement of the OER activity (10/100/500 mA cm −2 at 1.408/1.467/1.509 V RHE at 65 °C; Figure a and Table S11, Supporting Information). To investigate the stability, we performed a CP measurement at 500 mA cm −2 at 65 °C (inset Figure 5a).…”

“…[ 5 ] To perform water splitting efficiently, harsh conditions are necessary which include highly basic or acidic environments and elevated temperature (50–80 °C). [ 35–37 ] These conditions are an ongoing challenge for non‐noble‐metal catalysts that easily degrade. [ 12,38,39 ] Regarding the selective oxygenation of organic substrates, FDCA is an essential substrate in the polymer industry.…”

Pseudo‐Periodically Coupling NiO Lattice with CeO Lattice in Ultrathin Heteronanowire Arrays for Efficient Water Oxidation

“…Currently, the OER activity of TMOs precatalysts has been confirmed to be highly dependent on its transformation degree to corresponding (oxy)hydroxides. [ 22,23 ] Furthermore, the deep or complete phase transformation means the generation of more active species, thus contributing to an improved OER performance. [ 24,25 ] However, the phase reconstruction usually only initiates from the surface of TMOs particles.…”

Main Hydrogen Production Processes: An Overview

“…The use of noble metal-based electrodes could provide better performance however, cheaper alternative would be preferred. Recently MoO 2 -Ni arrays have been reported to exhibit a Pt-like activity at 25.0 • C [161], its heterogeneous components may avoid agglomeration under high-temperature catalytic conditions.…”