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The precise structural integration of single-atom and high-entropy-alloy features for energy electrocatalysis is highly appealing for energy conversion, yet remains a grand challenge. Herein, we report a class of single-atom Mo-tailored PdPtNiCuZn high-entropy-alloy nanosheets with dilute Pt-Pt ensembles and intrinsic tensile strain (Mo1-PdPtNiCuZn) as efficient electrocatalysts for enhancing the methanol oxidation reaction catalysis. The as-made Mo1-PdPtNiCuZn delivers an extraordinary mass activity of 24.55 A mgPt−1 and 11.62 A mgPd+Pt−1, along with impressive long-term durability. The planted oxophilic Mo single atoms as promoters modify the electronic structure of isolated Pt sites in the high-entropy-alloy host, suppressing the formation of CO adsorbates and steering the reaction towards the formate pathway. Meanwhile, Mo promoters and tensile strain synergistically optimize the adsorption behaviour of intermediates to achieve a more energetically favourable pathway and minimize the methanol oxidation reaction barrier. This work advances the design of atomically precise catalytic sites by creating a new paradigm of single atom-tailored high-entropy alloys, opening an encouraging pathway to the design of CO-tolerance electrocatalysts. Atomically precise modification of high-entropy alloys is highly appealing for electrocatalysis. Here, the authors design single-atom Mo-tailored high-entropy alloy nanosheets with dilute Pt-Pt ensembles and intrinsic tensile strain for promoting methanol electro-oxidation towards formate. [ABSTRACT FROM AUTHOR]

This document is a correction to an article titled "3D Vertically Aligned and Interconnected Porous Carbon Nanosheets as Sulfur Immobilizers for High Performance Lithium-Sulfur Batteries" published in Advanced Energy Materials. The correction addresses errors in several figures and text sections of the original article. The corrected figures and text provide accurate information about the reduction process, discharge capacities, long-term stability, and high-rate capability of the battery. The authors apologize for any inconvenience caused. [Extracted from the article]

Transition metal dichalcogenides (TMDs) show great potential as anodes for potassium‐ion batteries (PIBs) due to their high theoretical capacity and relatively low working potential. However, usually the conversion mechanism seriously hinders the long‐term cycle stability for PIBs due to the huge structural change. Herein, the synthesis of a class of ultrathin metallic 2H‐phase NbS2 nanosheets with large expanded interlayer spacing of 0.65 nm and high conductivity for boosting the potassium ion storage is reported. It is demonstrated that the as‐prepared NbS2 nanosheets show an unexpected intercalation mechanism for potassium ion storage, which is conceptually different from the well‐known intercalation‐conversion mechanism of typical TMDs. As a consequence, the ultrathin NbS2 nanosheets deliver superior rate capability (205.5 mAh g−1 at ultrahigh current density of 10 A g−1) and outstanding long‐term cycling performance (169.5 mAh g−1 at 5 A g−1 after 4000 cycles with a very low decay rate of 0.005% per cycle), representing the most stable TMD‐based anode materials for PIBs. Ex situ measurements and first‐principles calculations disclose and interpret that NbS2 nanosheets store potassium ions through only the intercalation mechanism without any conversion reaction taking place in the potassiation/depotassiation process, which highly improves the structural stability of electrode materials, hence promoting the long‐term cycle performance. [ABSTRACT FROM AUTHOR]

Despite the high theoretical specific capacity of transition‐metal disulfides anode for potassium‐ion batteries (PIBs), their development has been greatly hindered by dramatic capacity fading and poor cycle life. Herein, the synthesis of the new composite of Cu12Sb4S13 quantum dots/few‐layered Ti3C2 nanosheets (CAS‐Ti3C2) as advanced anode for boosting the K ion storage is reported. It is found that as‐made CAS‐Ti3C2 show a strong synergistic effect between quantum dots and Ti3C2 nanosheets mainly caused by the formation of the Ti–S bond, which can not only shorten the diffusion path of K+ but also accommodate the serious volumetric variation during the discharge/charge process. As expected, this specially designed CAS‐Ti3C2 anode exhibits a superior reversible specific capacity of 496.7 mAh g−1 at 100 mA g−1 after 200 cycles and 175.6 mAh g−1 at a high current density of 1.0 A g−1 even over 1800 cycles, preceding most of the reported transition‐metal disulfides quantum dots‐based anodes for PIBs. These comprehensive studies reveal that the excellent electrochemical property is attributed to the fast K+ diffusion kinetics and unique transformation and restorage mechanism between K+ with CAS‐Ti3C2 anode. [ABSTRACT FROM AUTHOR]

Designing a semiconductor‐based heterostructure photocatalyst for achieving the efficient separation of photogenerated electron‐hole pairs is highly important for enhancing H2 releasing photocatalysis. Here, a new class of Ni1−xCoxSe2–C/ZnIn2S4 hierarchical nanocages with abundant and compact ZnIn2S4 nanosheets/Ni1−xCoxSe2C nanosheets 2D/2D hetero–interfaces, is designed and synthesized. The constructed heterostructure photocatalyst exposes rich hetero‐junctions, supplying the broad and short transfer paths for charge carriers. The close contacts of these two kinds of nanosheets induce a strong interaction between ZnIn2S4 and Ni1−xCoxSe2C, improving the separation and transfer of photo‐generated electron‐hole pairs. As a consequence, the distinctive Ni1−xCoxSe2C/ZnIn2S4 hierarchical nanocages without using additional noble‐metal cocatalysts, display remarkable H2‐relaesing photocatalytic activity with a rate of 5.10 mmol g−1 h−1 under visible light irradiation, which is 6.2 and 30 times higher than those of fresh ZnIn2S4 nanosheets and bare Ni1−xCoxSe2C nanocages, respectively. Spectroscopic characterizations and theory calculations reveal that the strong interaction between ZnIn2S4 and Ni1−xCoxSe2C 2D/2D hetero‐interfaces can powerfully promote the separation of photo‐generated charge carriers and the electrons transfer from ZnIn2S4 to Ni1−xCoxSe2C. [ABSTRACT FROM AUTHOR]

Ultrathin nanosheet catalysts deliver great potential in catalyzing the oxygen reduction reaction (ORR), but encounter the ceiling of the surface atomic utilizations, thus presenting a challenge associated with further boosting catalytic activity. Herein, a kind of PdPtCu ultrathin nanorings with increased numbers of electrocatalytically active sites is reported, with the purpose of breaking the activity ceiling of conventional catalysts. The as‐made PdPtCu nanorings possess abundant high‐index facets at the edge of both the exterior and interior surfaces. An ultrahigh electrochemical active surface area of 92.2 m2 g–1PGM is achieved on this novel catalyst, much higher than that of the commercial Pt/C catalyst. The optimized Pd39Pt33Cu28/C shows a great enhanced ORR activity with a specific activity of 2.39 mA cm–2 and a mass activity of 1.97 A mg–1PGM at 0.9 V (versus RHE), as well as superior durability within 30 000 cycles. Density function theory calculations reveal that the high‐index facets and alloying Cu atoms can optimize the oxygen adsorption energy, explaining the enhanced ORR activity. Overcoming a key technical barrier in sub‐nanometer electrocatalysts, this work successfully introduces the hollow structures into the ultrathin nanosheets, heralding the exciting prospects of high‐performance ORR catalysts in fuel cells. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting plays a crucial role in the development of clean and renewable energy production and conversion, which is a promising pathway to reduce social dependence on fossil fuels. Thus, highly active, cost‐efficient, and robust catalysts must be developed to reduce the reaction overpotential and increase electrocatalytic efficiency. In this review, recent research efforts toward developing advanced electrocatalysts based on noble metals with outstanding performance for water splitting catalysis, which is mainly dependent on their structure engineering, are summarized. First, a simple description of the water‐splitting mechanism and some promising structure engineering strategies are given, including heteroatom incorporation, strain engineering, interface/hybrid engineering, and single atomic construction. Then, the underlying relationship between noble metal electronic/geometric structure and performance for water splitting is discussed with the assistance of theoretical simulation. Finally, a personal perspective is provided in order to highlight the challenges and opportunities for developing novel electrocatalysts suitable for a wide range of commercial uses in water splitting for structural engineering applications. [ABSTRACT FROM AUTHOR]

The strain effect, along with the ligand effect and synergistic effect, contributes primarily to the optimization of electrocatalytic activity and stability. The strain effect leads to a shift in the d-band center and alters binding energies toward adsorbates. Under electrocatalytic circumstances, the strain effect and ligand effect by and large function in combination; however, the decay and vanishing of the ligand effect precede the strain effect as the thickness of the shell in the core/shell structure or metallic overlayers on substrates increases. The strain effect on electrocatalytic activity can be well engineered by tuning the thickness of shells or atomic composition. Microstrain, or localized lattice strain, is another type of strain associated with structural defects such as grain boundaries and multi-twinning. In this review, we discuss the origin of the strain effect and how it affects electrocatalytic activity based on the d-band model. We present the structural characterization and quantitative determination of strain. Metal-based nanocrystals are basically grouped into two types of structures to which the strain engineering applies, i.e. lattice strain-associated structures (which include the general core/shell structure and solid solution alloy) and multiple defects-induced structures. Then analysis is performed on the correlation of strain and ligand effects and on the tuning strategies of the strain effect for electrocatalysis. After that, we use representative examples to demonstrate how strain engineering assists in typical electrocatalytic reactions on anodes and cathodes. Finally, we summarize and propose potential research areas in terms of enhancing electrocatalytic activities by strain engineering in the future. [ABSTRACT FROM AUTHOR]

Carbon nanomaterials are of great interest as the advanced supports of electrochemical active materials to enhance their performances, however, little knowledge has been put into understanding whether the pores of carbon nanomaterials as supports can tune the performance of energy storage and conversion devices due to the lack of methods for making porous carbon nanomaterials. Herein, this study demonstrates the use of 1D ordered mesoporous carbon nanorods (OMCRs) with high surface area as a new class of supports for 2D ultrathin MoS2 and MnO2 nanoplates to create the interesting hierarchical nanohybrids (MoS2@OMCRs and MnO2@OMCRs), respectively. With the significant role of OMCRs in optimizing the electron and charge transportation, MoS2@OMCRs exhibits remarkable activity for catalyzing hydrogen evolution reaction with a low onset overpotential of 105 mV and low Tafel slope of 40 mV dec−1, much better than those of MoS2@ carbon nanofibers. Significantly, the asymmetric supercapacitor based on MnO2@OMCRs as anode and OMCRS as cathode displays a maximum specific capacitance up to 100 F g−1 at 0.2 A g−1 and a high energy density of 55.2 W h kg−1 at the power density of 200 W kg−1 within a wide operating voltage of 2.0 V. The present work highlights the important role of the mesoporous carbon support in achieving the advanced energy storage and conversion. [ABSTRACT FROM AUTHOR]

One of the critical issues in the industrial development of fuel cells (e.g., proton exchange membrane fuel cells, direct methanol fuel cells and biofuel cells) is the high cost, serious intermediate tolerance, anode crossover, sluggish kinetics, and poor stability of the platinum (Pt) as the preferred electrocatalysts for the oxygen reduction reaction (ORR) at the cathode. The development of novel noble-metal-free electrocatalysts with low cost, high activity and practical durability for ORR has been considered as one of the most active and competitive fields in chemistry and materials science. In this critical review, we will summarize recent advances on engineering advanced carbon nanomaterials with different dimensions for the rational design and synthesis of noble-metal-free oxygen reduction electrocatalysts including heteroatom-doped carbon nanomaterials, transition metal-based nanoparticle (NP)–carbon nanomaterial composites and especially the stable iron carbide (Fe3C)-based NP–carbon nanomaterial composites. Introducing advanced carbon nanomaterials with high specific surface area and stable structure into the noble-metal-free ORR field has not only led to a maximized electrocatalyst surface area for the electron transfer but also resulted in enhanced electrocatalyst stability for long-term operation. Therefore, the rational design and synthesis of noble-metal-free electrocatalysts based on heteroatoms, transition metal-based NPs and Fe3C-based NP functionalized carbon nanomaterials are of special relevance for their ORR applications, and represents a rapidly growing branch of research. The demonstrated examples in this review will open new directions on designing and optimizing advanced carbon nanomaterials for the development of extremely active and durable earth-abundant cathodic catalysts for fuel cell applications. [ABSTRACT FROM AUTHOR]

Replacing the rare and precious platinum (Pt) electrocatalysts with earth-abundant materials for promoting the oxygen reduction reaction (ORR) at the cathode of fuel cells is of great interest in developing high-performance sustainable energy devices. However, the challenging issues associated with non-Pt materials are still their low intrinsic catalytic activity, limited active sites, and the poor mass transport properties. Recent advances in material sciences and nanotechnology enable rational design of new earth-abundant materials with optimized composition and fine nanostructure, providing new opportunities for enhancing ORR performance at the molecular level. This Review highlights recent breakthroughs in engineering nanocatalysts based on the earth-abundant materials for boosting ORR. [ABSTRACT FROM AUTHOR]

The rapid development of nanoscience and nanotechnology provides new opportunities for the sustainable progress of nanoscale catalysts (i.e., nanocatalysts). The introduction of nanocatalysts into electronic devices implants their novel functions into electronic sensing systems, resulting in the testing of many advanced electrochemical sensors and the fabrication of some highly sensitive, selective, and stable sensing platforms. In this Review, we will summarize recent significant progress on exploring advanced carbon nanomaterials (such as carbon nanotubes, graphene, highly ordered mesoporous carbons, and electron cyclotron resonance sputtered nanocarbon film) as nanoscale electrocatalysts (i.e., nanoelectrocatalysts) for constructing the catalytic nanointerfaces of electronic devices to achieve high-sensitivity and high-selectivity electrochemical sensors. Furthermore, different mechanisms for the extraordinary and unique electrocatalytic activities of these carbon nanomaterials will be also highlighted, compared and discussed. An outlook on the future trends and developments in this area will be provided at the end. Notably, to elaborate the nature of carbon nanomaterial, we will mainly focus on the electrocatalysis of single kind of carbon materials rather than their hybrid composite materials. We expect that advanced carbon nanomaterials with unique electrocatalytic activities will continue to attract increasing research interest and lead to new opportunities in various fields of research. [ABSTRACT FROM AUTHOR]

Herein, we report a facile strategy that allows one-pot preparation of highly open rhombic dodecahedral PtCu alloy nanoframes. Due to the highly open structures, the PtCu nanoframes exhibit enhanced catalytic performance in methanol electrooxidation, showing a new strategy to create highly active catalysts. [ABSTRACT FROM AUTHOR]

Summary: Nobel metal nanomaterials (NMNs) with interesting physical and chemical properties are ideal building blocks for engineering and tailoring nanoscale structures for specific technological applications. Particularly, effectively controlling the size, shape, architecture, composition, hybrid and microstructure of NMNs plays an important role on revealing their new or enhanced functions and application potentials such as fuel cell and analytical sensors. This review article focuses on recent advances on controllable synthesis and fuel cell and sensing applications of NMNs. First, recent contributions on developing a wet-chemical approach for the controllable synthesis of noble metal nanomaterials with a rich variety of shapes, e.g. single-component Pt, Pd, Ag and Au nanomaterials, multi-component core/shell, intermetallic or alloyed nanomaterials, metal fluorescent nanoclusters and metal nanoparticles-based hybrid nanomaterials, are summarized. Then diversified approaches to different types of NMNs-based nanoelectrocatalysts with the aim to enhance their activity and durability for fuel cell reactions are outlined. The review next introduces some exciting push in the use of NMNs as enhanced materials or reporters or labels for developing new analytical sensors including electrochemical, colorimetric and fluorescent sensors. Finally, we conclude with a look at the future challenges and prospects of the development of NMNs. [ABSTRACT FROM AUTHOR]

The emergence of graphene nanosheet (GN, 2010 Nobel Prize for Physics) has recently opened up an exciting new field in the science and technology of two-dimensional (2D) nanomaterials with continuously growing academic and technological impetus. GN exhibits unique electronic, optical, magnetic, thermal and mechanical properties arising from its strictly 2D structure and thus has many important technical applications. Actually, GN-based materials have enormous potential to rival or even surpass the performance of carbon nanotube-based counterparts, given that cheap, large-scale production and processing methods for high-quality GN become available. Therefore, the studies on GN in the aspects of chemistry, physical, materials, biology and interdisciplinary science have been in full flow in the past five years. In this critical review, from the viewpoint of chemistry and materials, we will cover recent significant advances in synthesis, molecular engineering, thin film, hybrids, and energy and analytical applications of the “star-material” GN together with discussion on its major challenges and opportunities for future GN research (315 references). [ABSTRACT FROM AUTHOR]

• 1D and 2D noble metal-based nanocrystals with various nanostructures are summarized. • Typical strategies for tuning the nanostructures of 1D and 2D noble metal-based nanocrystals are discussed. • The underlying mechanisms behind the structure-performance relationship are discussed. • Present challenges and perspectives to the research of 1D and 2D noble metal-based nanocrystals are provided. Recently, one- (1D) and two-dimensional (2D) noble metal-based nanocrystals have triggered tremendous interest due to their unique anisotropic structure in the field of electrochemical energy conversion. In this review, we summarize the latest research developments in 1D and 2D noble metal-based nanocrystals with various nanostructures, and their potential applications as electrocatalysts toward fuel-cell-related electrocatalysis. Five strategies including size, shape, composition, surface, and interface engineering are proposed to rationally design the nanoarchitectures of the 1D and 2D noble metal-based electrocatalysts. In addition, we also highlight the underlying mechanisms behind the structure-property relationship. Finally, we conclude the current challenges and give our perspectives on the development of high-performance 1D and 2D noble metal-based electrocatalysts. We hope this review could offer timely information on the research of 1D and 2D noble metal-based nanocrystals and provide guidance for regulating their electrocatalytic properties. [ABSTRACT FROM AUTHOR]

A novel one-step ionic liquid induced strategy has been reported for the controlled synthesis of carbon quantum dots (CQDs)/BiOX (X = Br, Cl) hybrid nanosheets with tunable CQDs loading contents. Such synthetic process allows the CQDs well dispersed on the surface of BiOX nanosheets. Three different types of pollutants, such as phenol rhodamine B (RhB), antibacterial agent ciprofloxacin (CIP) and endocrine disrupting chemical bisphenol A (BPA) were chosen to evaluate the photocatalytic activity of CQDs/BiOX composite nanosheets. They show very interesting CQDs loading content and X composition-dependent photocatalytic activity with 3 wt% CQDs/BiOBr nanosheets showing the highest photocatalytic activity (much better than pure BiOBr nanosheets) for the degradation of RhB, CIP and BPA under visible light irradiation. The results reveal that there are three factors in promoting the photocatalysis of 3 wt% CQD/BiOBr nanosheets: high visible light absorbance, high separation efficiency of photo-induced electrons and holes and lower resistance. The active species trap experiments and electron spin resonance (ESR) reveal that during the photocatalytic process, hole and O 2 − become the dominant species for the degradation of pollutants. The unique strategy demonstrated here can be extended to other hybrid nanosheet systems, making it possible to design and tune advanced photocatalysts for other important chemical and catalytic reactions. [ABSTRACT FROM AUTHOR]