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Electrocatalysts are the key components of electrochemical energy storage and conversion devices. High performance electrocatalysts can effectively reduce the energy barrier of the chemical reactions, thereby improving the conversion efficiency of energy devices. The electrocatalytic reaction mainly experiences adsorption and desorption of molecules (reactants, intermediates and products) on a catalyst surface, accompanied by charge transfer processes. Therefore, surface control of electrocatalysts plays a pivotal role in catalyst design and optimization. In recent years, many studies have revealed that the rational design and regulation of a defect structure can result in rearrangement of the atomic structure on the catalyst surface, thereby efficaciously promoting the electrocatalytic performance. However, the relationship between defects and catalytic properties still remains to be understood. In this review, the types of defects, synthesis methods and characterization techniques are comprehensively summarized, and then the intrinsic relationship between defects and electrocatalytic performance is discussed. Moreover, the application and development of defects are reviewed in detail. Finally, the challenges existing in defective electrocatalysts are summarized and prospected, and the future research direction is also suggested. We hope that this review will provide some principal guidance and reference for researchers engaged in defect and catalysis research, better help researchers understand the research status and development trends in the field of defects and catalysis, and expand the application of high-performance defective electrocatalysts to the field of electrocatalytic engineering. [ABSTRACT FROM AUTHOR]

Hydrogen, a clean resource with high energy density, is one of the most promising alternatives to fossil. Proton exchange membrane water electrolyzers are beneficial for hydrogen production because of their high current density, facile operation, and high gas purity. However, the large‐scale application of electrochemical water splitting to acidic electrolytes is severely limited by the sluggish kinetics of the anodic reaction and the inadequate development of corrosion‐ and highly oxidation‐resistant anode catalysts. Therefore, anode catalysts with excellent performance and long‐term durability must be developed for anodic oxygen evolution reactions (OER) in acidic media. This review comprehensively outlines three commonly employed strategies, namely, defect, phase, and structure engineering, to address the challenges within the acidic OER, while also identifying their existing limitations. Accordingly, the correlation between material design strategies and catalytic performance is discussed in terms of their contribution to high activity and long‐term stability. In addition, various nanostructures that can effectively enhance the catalyst performance at the mesoscale are summarized from the perspective of engineering technology, thus providing suitable strategies for catalyst design that satisfy industrial requirements. Finally, the challenges and future outlook in the area of acidic OER are presented. [ABSTRACT FROM AUTHOR]

Nanoscale defects can induce the effective modulation of carrier concentration, mobility, and phonon scattering to secure high thermoelectric performance in semiconductors. However, it is still limited to effectively controlling nanoscale defects in thermoelectric materials. Here, argon plasma bombardment is employed to introduce a large number of point defects and dislocations in microcrystalline SnSe powders, synthesized by a solvothermal method. After sintering these powders into polycrystalline bulk materials, bulk SnSe shows the ZT increasing by up to 66.7% (from 0.36 to 0.6 at 773 K). Through detailed micro/nanostructure characterizations and first‐principles calculations, the underlying mechanism is elucidated for the evaluation of thermoelectric performance. This work provides a deep understanding of the mechanism of nanoscale defects in modulating thermoelectric performance and presents experimental evidence and experience for the design and synthesis of efficient thermoelectric materials, making significant contributions to future green energy technologies. [ABSTRACT FROM AUTHOR]

Photoelectrochemical solar to hydrogen conversion is a promising approach to solve energy and environmental problems. One of the paramount challenges to overcome is to achieve high solar to hydrogen efficiency while retaining stable service behavior without photocorrosion of the photoanode. In this study, a hydrogel‐enabled dual‐shielding (FeCoOx/PAAM) strategy is reported to improve efficiency and suppress photocorrosion of photoanode during solar water splitting especially in a high‐intensity illumination. Anodic photocorrosion of BiVO4 photoanodes involves the chemical and physical construction changes under the conditions of light field, electric field, and electrolyte. The utilization of FeCoOx/PAAM on BiVO4 inhibits the improvement of oxygen evolution reaction kinetics, bubble dynamics, and blocking ion dissolution diffusion, which effectively suppresses anodic photocorrosion and simultaneously improves efficiency of BiVO4 photoanode. The improved BiVO4/FeCoOx/PAAM photoanode shows a superior photocurrent density of 19.88 mA cm−2 at 1.23 V versus RHE, and a high charge separation efficiency of 98% with enhanced stability over 60 h (300 mW cm−2). This study contributes to developing a universal method of photoanode protection to anti‐photocorrosion, facilitating the development of high‐efficiency, high‐stability, and pollution‐free hydrogen production. [ABSTRACT FROM AUTHOR]

On 16 June 2023, the United Nations Environment Programme highlighted the severity of nitrogen pollution faced by humans and called for joint action for sustainable nitrogen use. Excess nitrogenous waste (NW: NO, NO2, NO2−, NO3−, etc.) mainly arises from the use of synthetic fertilisers, wastewater discharge, and fossil fuel combustion. Although the amount of NW produced can be minimised by reducing the use of nitrogen fertilisers and fossil fuels, the necessity to feed seven billion people on Earth limits the utility of this approach. Compared to current industrial processes, electrocatalytic NW reduction or CO2–NW co-reduction offers a potentially greener alternative for recycling NW and producing high-value chemicals. However, upgrading this technology to connect upstream and downstream industrial chains is challenging. This viewpoint focuses on electrocatalytic NW reduction, a cutting-edge technology, and highlights the challenges in its practical application. It also discusses future directions to meet the requirements of upstream and downstream industries by optimising production processes, including the pretreatment and supply of nitrogenous raw materials (e.g. flue gas and sewage), design and macroscopic preparation of electrocatalysts, and upscaling of reactors and other auxiliary equipment. [ABSTRACT FROM AUTHOR]

Electrocatalytic hydrogenation (ECH) is a burgeoning strategy for the sustainable utilization of hydrogen. However, how to effectively suppress the competitive hydrogen evolution reaction (HER) is a big challenge to ECH catalysis. In this study, amine (NH2R)‐coordinated Pd nanoparticles loaded on carbon felt (Pd@CF) as a catalyst is successfully synthesized by a one‐step solvothermal reduction method using oleylamine as the reducing agent. An exceptional ECH reactivity on benzaldehyde is achieved on the optimal Pd@CF catalyst in terms of a high conversion (89.7%) and selectivity toward benzyl alcohol (89.8%) at −0.4 V in 60 min. Notably, the Faradaic efficiency for producing benzyl alcohol is up to 90.2%, much higher than that catalyzed by Pd@CF‐without N‐group (41.1%) and thecommercial Pd/C (20.9%). The excellent ECH performance of Pd@CF can be attributed to the enriched electrons on Pd surface resulted from the introduction of NH2R groups, which strengthens both the adsorption of benzaldehyde and the adsorbed hydrogen (Hads) on Pd, preventing the combination of Hads to form H2, that is, inhibiting the HER. This study gives a new insight into design principles of highly efficient electrocatalysts for the hydrogenation of unsaturated aldehydes molecules. [ABSTRACT FROM AUTHOR]