Electron-Donating Zr Induces Suppressed Ru Over-Oxidation and Accelerated Deprotonation Process Toward Efficient and Durable Water Electrolysis.

The scarcity of cost-effective and durable iridium-free anode electrocatalysts for the oxygen evolution reaction (OER) poses a significant challenge to the widespread application of the proton exchange membrane water electrolyzer (PEMWE). To address the electrochemical oxidation and dissolution issues of Ru-based electrocatalysts, an electron-donating modification strategy is developed to stabilize WRuO under harsh oxidative conditions. The optimized catalyst with a low Zirconium doping (Zr, 1 wt.

Monosymmetric Fe-N sites enabling durable proton exchange membrane fuel cell cathode by chemical vapor modification.

The limited durability of metal-nitrogen-carbon electrocatalysts severely restricts their applicability for the oxygen reduction reaction in proton exchange membrane fuel cells. In this study, we employ the chemical vapor modification method to alter the configuration of active sites from FeN to the stable monosymmetric FeN+N', along with enhancing the degree of graphitization in the carbon substrate. This improvement effectively addresses the challenges associated with Fe active center leaching caused by N-group protonation and free radicals attack due to the 2-electron oxygen reduction reaction.

Single atom sites as CO scavenger to allow for crude hydrogen usage in PEMFC.

Nanosized Pt catalysts are the catalyst-of-choice for proton exchange membrane fuel cell (PEMFC) anode, but are limited by their extreme sensitivity to CO in parts per million (ppm) level, thereby making the use of ultrapure H a prerequisite to ensure acceptable performance. Herein, we confront the CO poisoning issue by bringing the Ir/Rh single atom sites to synergistically working with their metallic counterparts. In presence of 1000 ppm CO, the catalyst represents not only undisturbed H oxidation reaction (HOR) catalytic behavior in electrochemical cell, but also unparalleled peak power density at 643 mW cm in single cell, 27-fold in mass activity of the best PtRu/C catalysts available.

Operando formation of highly efficient electrocatalysts induced by heteroatom leaching.

Heterogeneous nano-electrocatalysts doped with nonmetal atoms have been studied extensively based on the so-called dopant-based active sites, while little attention has been paid to the stability of these dopants under working conditions. In this work, we reveal significantly, when the redox working potential is too low negatively or too high positively, the active sites based on these dopants actually tend to collapse. It means that some previously observed "remarkable catalytic performance" actually originated from some unknown active sites formed in situ.

Intrinsic spin shielding effect in platinum-rare-earth alloy boosts oxygen reduction activity.

Oxygen reduction reactions (ORRs) involve a multistep proton-coupled electron process accompanied by the conversion of the apodictic spin configuration. Understanding the role of spin configurations of metals in the adsorption and desorption of oxygen intermediates during ORRs is critical for the design of efficient ORR catalysts. Herein, a platinum-rare-earth-metal-based alloy catalyst, PtGd, is introduced to reveal the role of spin configurations in the catalytic activity of materials.

Customized reaction route for ruthenium oxide towards stabilized water oxidation in high-performance PEM electrolyzers.

The poor stability of Ru-based acidic oxygen evolution (OER) electrocatalysts has greatly hampered their application in polymer electrolyte membrane electrolyzers (PEMWEs). Traditional understanding of performance degradation centered on influence of bias fails in describing the stability trend, calling for deep dive into the essential origin of inactivation. Here we uncover the decisive role of reaction route (including catalytic mechanism and intermediates binding strength) on operational stability of Ru-based catalysts.

Enhanced Acidic Water Oxidation by Dynamic Migration of Oxygen Species at the Ir/Nb O Catalyst/Support Interfaces.

Catalyst/support interaction plays a vital role in catalysis towards acidic oxygen evolution (OER), and the performance reinforcement is currently interpreted by either strain or electron donation effect. We herein report that these views are insufficient, where the dynamic evolution of the interface under potential bias must be considered. Taking Nb O supported iridium (Ir/Nb O ) as a model catalyst, we uncovered the dynamic migration of oxygen species between IrO and Nb O during OER.

Synthesis of Co/CeO hetero-particles with abundant oxygen-vacancies supported by carbon aerogels for ORR and OER.

It is highly significant for the fabrication of rechargeable metal-air batteries to develop cost-efficient and high-performance electrocatalysts of bifunctionality for both oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Herein, we demonstrate a hybrid composed of CeO-decorated Co nanoparticles supported on three-dimensionally porous carbon aerogels (Co-CeO/C aerogels) as a superior bifunctional electrocatalyst. The preparation of Co-CeO/C aerogels depends on the formation of a novel CeCl/KCo(CN)-chitosan (CS) hydrogel, during which the cyanide groups of KCo(CN) combines the hydroxyls in CS by hydrogen bridges, accompanying with the substitution of chloride groups in CeCl by cyanide groups in KCo(CN).

Proton exchange membrane fuel cells powered with both CO and H.

The CO electrooxidation is long considered invincible in the proton exchange membrane fuel cell (PEMFC), where even a trace level of CO in H seriously poisons the anode catalysts and leads to huge performance decay. Here, we describe a class of atomically dispersed IrRu-N-C anode catalysts capable of oxidizing CO, H, or a combination of the two. With a small amount of metal (24 μg⋅cm) used in the anode, the H fuel cell performs its peak power density at 1.

Carbon monoxide powered fuel cell towards H-onboard purification.

Proton exchange membrane fuel cells (PEMFCs) suffer extreme CO poisoning even at PPM level (<10 ppm), owning to the preferential CO adsorption and the consequential blockage of the catalyst surface. Herein, however, we report that CO itself can become an easily convertible fuel in PEMFC using atomically dispersed Rh catalysts (Rh-N-C). With CO to CO conversion initiates at 0 V, pure CO powered fuel cell attains unprecedented power density at 236 mW cm, with maximum CO turnover frequency (64.

Ultrasound sonochemical synthesis of amorphous SbS-graphene composites for sodium-ion batteries.

Different from traditional methods, ultrasound sonochemical synthesis can create very special reaction conditions by virtue of the effects of acoustic cavitation. The localized spots in the medium liquids can reach the temperature of ~5000 K, and the pressure of ~1000 bar with the treatment of ultrasonic irradiation. The extreme conditions make it possible to fabricate a series of nanostructured materials with peculiar properties.

Fundamental understanding of the acidic oxygen evolution reaction: mechanism study and state-of-the-art catalysts.

The oxygen evolution reaction (OER), as the anodic reaction of water electrolysis (WE), suffers greatly from low reaction kinetics and thereby hampers the large-scale application of WE. Seeking active, stable, and cost-effective OER catalysts in acidic media is therefore of great significance. In this perspective, studying the reaction mechanism and exploiting advanced anode catalysts are of equal importance, where the former provides guidance for material structural engineering towards a better catalytic activity.