Publications by authors named "Yunhu Han"

The simultaneous regulation of particle size, surface coordinated environment and composition for Pt-based intermetallic compound (Pt-IMC) nanoparticles to manipulate their reactivity for energy storage is of great importance. Herein, we report a general synthetic method for Pt-IMCs using SBA-15 for coordination-in-pipe engineering. The particle size can be regulated to 3-9 nm by carrying out the coordination in pipes with different diameters and the coordination number of the interface metal atoms can be adjusted by altering the N source.

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Anion exchange membrane fuel cells (AEMFCs) are one of the ideal energy conversion devices. However, platinum (Pt), as the benchmark catalyst for the hydrogen oxidation reaction (HOR) of AEMFCs anodes, still faces issues of insufficient performance and susceptibility to CO poisoning. Here, we report the Joule heating-assisted synthesis of a small sized RuPt single-atom alloy catalyst loaded on nitrogen-doped carbon modified with single W atoms (s-RuPt@W/NC), in which the near-range single Ru atoms on the RuPt nanoparticles and the long-range single W atoms on the support simultaneously modulate the electronic structure of the active Pt-site, enhancing alkaline HOR performance of s-RuPt@W/NC.

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We reported an exogenous nitrogen-doped method to synthesize a bifunctional electrocatalyst with oxygen reduction and evolution reaction activity. This electrocatalyst displays excellent ORR ( = 0.9 V RHE) and OER (potential = 1.

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Article Synopsis
  • * The resulting catalyst, LD-B/RuO2, demonstrates a low overpotential of 175 mV and can maintain effective oxygen evolution for about 1.6 months under specific conditions, showcasing impressive durability.
  • * The study highlights that B-doping leads to a tough, disordered structure in the catalyst, promoting both its activity and stability, thus offering a promising alternative for future non-iridium-based electrolyzer applications.
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  • Noble metal-based nanoalloys (NAs) have potential in energy and catalysis, but their synthesis is challenging due to the need for small-sized alloys with controllable shapes.
  • A new synthesis method, combining cation exchange and spatial confinement (CESC), was developed, creating a library of 21 NAs that can be controlled by adjusting non-precious metals.
  • The framed PtCu/HCN NA showed impressive electrocatalytic performance for both the methanol oxidation reaction and hydrogen evolution reaction, outperforming commercial catalysts in activity and stability.
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Ruthenium (Ru) is considered a promising candidate catalyst for alkaline hydroxide oxidation reaction (HOR) due to its hydrogen binding energy (HBE) like that of platinum (Pt) and its much higher oxygenophilicity than that of Pt. However, Ru still suffers from insufficient intrinsic activity and CO resistance, which hinders its widespread use in anion exchange membrane fuel cells (AEMFCs). Here, we report a hybrid catalyst (RuCo)/N-CNT consisting of dilute RuCo alloy nanoparticles and atomically single Ru and Co atoms on N-doped carbon nanotubes The catalyst exhibits a state-of-the-art activity with a high mass activity of 7.

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The generation of green hydrogen by water splitting is identified as a key strategic energy technology, and proton exchange membrane water electrolysis (PEMWE) is one of the desirable technologies for converting renewable energy sources into hydrogen. However, the harsh anode environment of PEMWE and the oxygen evolution reaction (OER) involving four-electron transfer result in a large overpotential, which limits the overall efficiency of hydrogen production, and thus efficient electrocatalysts are needed to overcome the high overpotential and slow kinetic process. In recent years, noble metal-based electrocatalysts (e.

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Development of efficient and easy-to-prepare low-cost oxygen reaction electrocatalysts is essential for widespread application of rechargeable Zn-air batteries (ZABs). Herein, we mixed NaCl and ZIF-8 by simple physical milling and pyrolysis to obtain a metal-free porous electrocatalyst doped with Cl (mf-pClNC). The mf-pClNC electrocatalyst exhibits a good oxygen reduction reaction (ORR) activity (E =0.

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Article Synopsis
  • Pt-based catalysts for water electrolyzers face issues like low activity, stability, and CO tolerance.
  • A new bifunctional catalyst combining Pt-Er alloy clusters and single atoms of Pt and Er shows significantly improved performance, with mass activity and turnover frequency (TOF) much higher than standard Pt/C.
  • The catalyst maintains stable operation in harsh acidic environments for over 1200 hours, highlighting its potential for practical industrial applications in hydrogen evolution and oxidation reactions.
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  • * Current research emphasizes the use of single-atom catalysts (SACs) due to their high efficiency and catalytic performance in CO conversion.
  • * This review analyzes research advancements, challenges, and the effects of support materials on SACs, aiming to inspire future designs of effective CO reduction catalysts.
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Hydrogen energy is regarded as the ultimate energy source for future human society, and the preparation of hydrogen from water electrolysis is recognized as the most ideal way. One of the key factors to achieve large-scale hydrogen production by water splitting is the availability of highly active and stable electrocatalysts. Although non-precious metal electrocatalysts have made great strides in recent years, the best hydrogen evolution reaction (HER) electrocatalysts are still based on noble metals.

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Metal nanoparticles occupy an important position in electrocatalysis. Unfortunately, by using conventional synthetic methodology, it is a great challenge to realize the monodisperse composition/structure of metal nanoparticles at the atomic level, and to establish correlations between the catalytic properties and the structure of individual catalyst particles. For the study of well-defined nanocatalysts, great advances have been made for the successful synthesis of nanoparticles with atomic precision, notably ligand-passivated metal nanoclusters.

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Recognizing and controlling the structure-activity relationships of single-atom catalysts (SACs) is vital for manipulating their catalytic properties for various practical applications. Herein, Fe SACs supported on nitrogen-doped carbon (SA-Fe/CN) are reported, which show high catalytic reactivity (97% degradation of bisphenol A in only 5 min), high stability (80% of reactivity maintained after five runs), and wide pH suitability (working pH range 3-11) toward Fenton-like reactions. The roles of different N species in these reactions are further explored, both experimentally and theoretically.

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Flexible Zn-air batteries (ZABs) draw much attention due to the merits of high energy density, stability, and safety, and show potential applications for wearable devices. However, the development of flexible ZABs with great energy density, high round-trip efficiency, and long cycle life for practical applications is highly restricted by the lack of highly active oxygen catalysts, high ion-conducting solid-state electrolytes, appropriate Zn anodes, and advanced battery configuration. Promising oxygen catalysts should possess both, superior oxygen reduction reaction and oxygen evolution reaction performance and can be directly used as self-supporting cathodes without loading catalysts on support materials such as carbon cloth.

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Metal-gas batteries draw a lot of attention due to their superiorities in high energy density and stable performance. However, the sluggish electrochemical reactions and associated side reactions in metal-gas batteries require suitable catalysts, which possess high catalytic activity and selectivity. Although precious metal catalysts show a higher catalytic activity, high cost of the precious metal catalysts hinders their commercial applications.

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The rechargeable Zn-air batteries as an environmentally friendly sustainable energy technology have been extensively studied. However, it is still a challenge to develop non-noble metal bifunctional catalysts with high oxygen reduction as well as oxygen evolution reaction (ORR and OER) activity and superior durability, which limit the large-scale application of rechargeable Zn-air batteries. Herein, we synthesized an ultrastable FeCo bifunctional oxygen electrocatalyst on Se-doped CNTs (FeCo/Se-CNT) via a gravity guided chemical vapor deposition (CVD) strategy.

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Electrocatalysis of the four-electron oxygen reduction reaction (ORR) provides a promising approach for energy conversion, storage, and oxygen monitoring. However, it is always accompanied by the reduction of hydrogen peroxide (HO) on most employed catalysts, which brings down the electrocatalytic selectivity. Here, we report a single-atom Co-N electrocatalyst for the four-electron ORR at an onset potential of 0.

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The oxidation of intracellular biomolecules by reactive oxygen species (ROS) forms the basis for ROS-based tumor therapy. However, the current therapeutic modalities cannot catalyze H O and O concurrently for ROS generation, thereby leading to unsatisfactory therapeutic efficacy. Herein, it is reported a bioinspired hollow N-doped carbon sphere doped with a single-atom copper species (Cu-HNCS) that can directly catalyze the decomposition of both oxygen and hydrogen peroxide to ROS, namely superoxide ion (O • ) and the hydroxyl radical (•OH), respectively, in an acidic tumor microenvironment for the oxidation of intracellular biomolecules without external energy input, thus resulting in an enhanced tumor growth inhibitory effect.

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Noble metals play a momentous role in heterogeneous catalysis but still face a huge challenge in selectivity control. Herein, we report isolating contiguous Pt atoms and forming Pt-Zn intermetallic nanoparticles as an effective strategy to optimize the selectivity of Pt catalysts. Contiguous Pt atoms are isolated into single atoms and Pt-Zn intermetallic nanoparticles are formed which are supported on hollow nitrogen-doped carbon nanotubes (PtZn/HNCNT), as confirmed by aberration-corrected high-resolution transmission electron microscopy and X-ray absorption spectrometry measurements.

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In cooperative catalysis, the combination of chemo- and biocatalysts to perform one-pot reactions is a powerful tool for the improvement of chemical synthesis. Herein, UiO-66-NH was employed to stepwise immobilize Pd nanoparticles (NPs) and Candida antarctica lipase B (CalB) for the fabrication of biohybrid catalysts for cascade reactions. Distinct from traditional materials, UiO-66-NH has a robust but tunable structure that can be utilized with a ligand exchange approach to adjust its hydrophobicity, resulting in excellent catalyst dispersity in diverse reaction media.

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Development of single-site catalysts supported by ultrathin two-dimensional (2D) porous matrix with ultrahigh surface area is highly desired but also challenging. Here we report a cocoon silk chemistry strategy to synthesize isolated metal single-site catalysts embedded in ultrathin 2D porous N-doped carbon nanosheets (M-ISA/CNS, M = Fe, Co, Ni). X-ray absorption fine structure analysis and spherical aberration correction electron microscopy demonstrate an atomic dispersion of metal atoms on N-doped carbon matrix.

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Single-atom catalysts (SACs) have been explored widely as potential substitutes for homogeneous catalysts. Isolated cobalt single-atom sites were stabilized on an ordered porous nitrogen-doped carbon matrix (ISAS-Co/OPNC). ISAS-Co/OPNC is a highly efficient catalyst for acceptorless dehydrogenation of N-heterocycles to release H .

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Correction for 'Isolated Fe and Co dual active sites on nitrogen-doped carbon for a highly efficient oxygen reduction reaction' by Diyang Zhang et al., Chem. Commun.

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We successfully prepared Fe and Co isolated single atoms on metal-organic framework derived nitrogen-doped carbon (FeCo-ISAs/CN) by an adsorption-calcination strategy. The obtained FeCo-ISAs/CN exhibited top-level catalytic reactivity for the alkaline oxygen reduction reaction (ORR) with a half-wave potential of 0.920 V, which was 70 mV more positive than that of commercial Pt/C.

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