Hao Wang

• PhD
• Assistant Professor at Nanjing University

The activity and accessibility of MoS2 edge sites are critical to deliver high hydrogen evolution reaction (HER) efficiency. Here, a porous carbon network confining ultrasmall N-doped MoS2 nanocrystals (N-MoS2/CN) is fabricated by a self-templating strategy, which realizes synergistically structural and electronic modulations of MoS2 edges. Experim...

Transition metal nitrides (TMNs), by virtue of their unique electronic structure, high electrical conductivity, superior chemical stability, and excellent mechanical robustness, have triggered tremendous research interest over the past decade, and showed great potential for electrochemical energy conversion and storage. However, bulk TMNs usually s...

The exploration of efficient electrocatalysts for energy conversion is important for green energy development. Owing to their high surface areas and unusual electronic structure, 2D electrocatalysts have attracted increasing interest. Among them, non‐van der Waals (non‐vdW) 2D materials with numerous chemical bonds in all three dimensions and novel...

Superconducting nanocircuits, which are usually fabricated from superconductor films, are the core of superconducting electronic devices. While emerging transition-metal dichalcogenide superconductors (TMDSCs) with exotic properties show promise for exploiting new superconducting mechanisms and applications, their environmental instability leads to...

Ultrathin superconducting films are the basis of superconductor devices. van der Waals (vdW) NbSe2 with noncentrosymmetry exhibits exotic superconductivity and shows promise in superconductor electronic devices. However, the growth of inch-scale NbSe2 films with layer regulation remains a challenge because vdW structural material growth is strongly...

Photoelectrochemical water splitting is one of the most promising and appealing strategies for converting sunlight into sustainable hydrogen energy and has received increasing attention. Among the potential photocatalysts, BiVO4 has attracted particular attention as a photoanode material because of its appropriate bandgap (2.4 eV) and favorable ban...

The noise equivalent temperature difference (NETD) indicates the minimum temperature difference resolvable by an infrared detector. The lower the NETD is, the better the sensor can register small temperature differences. In this work, we proposed a strategy to achieve a high temperature resolution using a superconducting nanowire single-photon dete...

Superconducting nanowire single-photon detectors (SNSPDs) have been widely applied in quantum information and deep-space exploration owing to their high detection efficiency, low dark count rate, and wide spectral response. In particular, the heat transfer in SNSPDs largely affects their performance parameters (e.g. quantum efficiency, count rates...

As a sustainable energy technology, electrocatalytic energy conversion requires electrocatalysts, which greatly motivates the exploitation of high‐performance electrocatalysts based on nonprecious metals. Molybdenum‐based nanomaterials have demonstrated promise as electrocatalysts because of their unique physiochemical and electronic properties. Am...

The demand for the exploration of highly active and durable electro/photocatalysts for renewable energy conversion has experienced a significant surge in recent years. Metal‐organic frameworks (MOFs), by virtue of their high porosity, large surface area, and modifiable metal centers and ligands, have gained tremendous attention and demonstrated pro...

Atomically doping in thin film poses a significant challenge due to the potential for dopant precipitation caused by self‐purification effects. This challenge is particularly pronounced in the case of doping monolayers of photoluminescent transition metal dichalcogenides, where high energy barriers are also required to break the in‐plane bonds betw...

Superconducting nanowire single-photon detector is a kind of refrigerated photon-counting detector with high performance, which can detect extremely weak signals. The noise of optical system is an important factor limiting the sensitivity of infrared superconducting nanowire single-photon detector. In order to improve the sensitivity of infrared de...

Superconductor nanodevices serve significant platforms for solid-state quantum systems, such as quantum computer and quantum detector. And the out-of-equilibrium phenomena always plays an important role in superconductor nanodevices. Here we reported an incoherent superconducting nanowire phonon detector for revealing the out-of-equilibrium phenome...

The investigation of photon response in the superconducting state of interfacial superconductors holds both fundamental and practical significance, yet it remains largely unexplored. Here, we report an energy-sensitive photodetector utilizing a microstrip patterned on an interfacial superconductor (LaAlO3/KTaO3), achieving photon response spanning...

Quantum efficiency is one of the most important performance metrics for superconducting nanowire single-photon detectors (SNSPDs). Specifically, near-infrared NbN-SNSPDs with high quantum efficiency are extremely desirable in quantum communications. However, due to the high energy gap of NbN, it is difficult to achieve a saturated quantum efficienc...

Engineering precious metals’ sub‐nanometer cluster on 2D earth‐abundant supports provides a promising approach for the development of high‐efficient electrocatalysts in pursuit of green hydrogen. Herein, a novel solid phase deposition approach is demonstrated for the homogenous confinement of atomically thin Pt nanoclusters on 2D delta‐MoN as a via...

Although many multiplexed arrays of a superconducting nanowire single-photon detector (SNSPD) have been reported, it is still a major challenge to develop pixel-level readout arrays with high efficiency, parallel detection, and fast processing for real-time imaging. Here, we report a SNSPD array with inductor-shaping pulses for approaching the pixe...

Precisely acquiring the timing information of individual X-ray photons is important in both fundamental research and practical applications. The timing precision of commonly used X-ray single-photon detectors remains in the range of one hundred picoseconds to microseconds. In this work, we report on high-timing-precision detection of single X-ray p...

As a competitive technology, the superconducting nanowire single-photon detector (SNSPD) is developing from a single-pixel to array architecture; however, it is a major challenge for reading array detectors. We propose an encodable trigger through the thermal coupling of two adjacent superconducting nanowires, which can read a current pulse with mi...

MXenes have attracted increasing attention because of their rich surface functional groups, high electrical conductivity, and outstanding dispersibility in many solvents, and have demonstrated competitive efficiency in energy storage and conversion applications. However, the restacking nature of MXene nanosheets like other two-dimensional (2D) mate...

Electron beam lithography uses an accelerated electron beam to fabricate patterning on an electron-beam-sensitive resist but requires complex dry etching or lift-off processes to transfer the pattern to the substrate or film on the substrate. In this study, etching-free electron beam lithography is developed to directly write a pattern of various m...

Fiber components form the standard not only in modern telecommunication but also for future quantum information technology. For high-performance single-photon detection, superconducting nanowire single-photon detectors (SPDs) are typically fabricated on a silicon chip and fiber-coupled for easy handling and usage. The fiber-to-chip interface hinder...

The characterization and manipulation of polarization state at single photon level are of great importance in research fields such as quantum information processing and quantum key distribution, where photons are normally delivered using single mode optical fibers. To date, the demonstrated polarimetry measurement techniques based on a superconduct...

Facing the demand for applications such as wide-area terrain mapping and space-based atmospheric measurements, there is an urgent need to develop miniaturized single-photon detection systems with low power consumption that can be adapted to airborne platforms. Superconducting nanowire single-photon detectors (SNSPDs) have been applied to quantum in...

The development of advanced nanomaterials is urgent for electrocatalytic energy conversion applications. Recently, 2D nanomaterial‐derived heterogeneous electrocatalysts have shown great promise for both fundamental research and practical applications owing to their extremely high surface‐to‐volume ratio and tunable geometric and electronic propert...

Electrochemical nitrogen reduction reaction (NRR) is considered a sustainable approach that endows NH3 production from N2 and H2O under ambient conditions. Due to the sluggish adsorption/activation of N2 and the strong competition with the hydrogen evolution reaction, advanced NRR electrocatalysts with both high activity and selectivity are require...

Although Ti3C2Tx MXene is a promising material for many applications such as catalysis, energy storage, electromagnetic interference shielding due to its metallic conductivity and high processability, it’s poor resistance to oxidation at high temperatures makes its application under harsh environments challenging. Here, we report an air-stable Ti3C...

Superconducting nanowire single photon detectors (SNSPDs) have been extensively investigated due to their superior characteristics, including high system detection efficiency, low dark count rate and short recovery time. The polarization sensitivity introduced by the meandering-type superconductor nanowires is an intrinsic property of SNSPD, which...

In this Letter, we report on pattern engineering in superconducting microstrips to achieve a fast and efficient detection of a single-photon over a large detection area. The proposed detector is composed of hole-patterned superconductor microstrips fabricated with a 5-nm-thick amorphous molybdenum silicide film. It exhibits a saturated internal det...

Lidar has already achieved long-distance and high-accuracy detection due to the improved sensitivity and timing accuracy of single-photon detectors (SPDs). However, single-photon Lidar systems based on semiconductor detectors are usually susceptible to dark counts and afterpulsing. Recently, superconducting nanowire single-photon detectors (SNSPDs)...

The efficiency and stability of lithium-sulfur (Li-S) batteries remain limited due to the slow redox kinetics, uncontrollable polysulfide shuttling, and irreversible lithium dendrite growth. Herein, we report a bifunctional composite of heterostructured ZnO/Co3O4 nanocrystals on a 3D hierarchical reduced graphene oxide/carbon nanotubes skeleton ([e...

In this Letter, we report on a device with which to resolve photon numbers and positions simultaneously, using single-channel readout from superconducting nanowire single-photon detectors (SNSPDs). The nanowires in the SNSPDs are connected in series with parallel resistors for producing response pulses with different amplitudes, whose values obey a...

A traditional concept proposes that the suppression of the transition temperature Tc in an amorphous nanobelt is driven by enhanced disorder, which accounts for localized Cooper pairs. However, in this paper, we observe Tc suppression in an amorphous molybdenum-silicide (MoSi) nanobelt, which scales as the inverse square of the width but contradict...

Phase slip is the intrinsic fluctuation of the order parameter and leads to the dissipation of superconductors. Here we propose a photon-assisted phase-slip model in superconducting nanowires to explain the phase-slip rate under photon irradiation. In this phenomenological model, incident photons destroy large quantities of Cooper pairs and reduce...

Potassium ion hybrid capacitors (KICs) have drawn tremendous attention for large-scale energy storage applications because of their high energy and power densities and the abundance of potassium sources. However, achieving KICs with high capacity and long lifespan remains challenging because the large size of potassium ions causes sluggish kinetics...

Superconducting nanowire single-photon detectors (SNSPDs) are currently one of the most mainstream single-photon detectors with excellent comprehensive performance, including low time jitter, high efficiency, low dark count and wide spectrum. However, the traditional single-pixel SNSPD suffers from a lack of spatial resolution and a small photosens...

Superconducting nanowire single-photon detector (SNSPD) is one of the most mainstream single-photon detectors at present, which possesses excellent comprehensive performance, including low time jitter, high efficiency, low dark count, and wide spectrum. However, the traditional single-pixel SNSPD suffers a lack of spatial resolution and a small pho...

High-performance mid-wave and long-wave infrared single-photon detectors not only have significant research value in the fields of infrared astronomy and defense technology, but also are the challenges in the field of single-photon detection technology. Superconducting nanowire single-photon detectors (SNSPDs) have shown excellent performances in t...

Two-dimensional materials have been demonstrated as promising toolboxes for optoelectronics. Transition metal carbides and nitrides (MXenes), members of an emerging family of two-dimensional materials, have drawn extensive attention in optoelectronics owing to their excellent conductivity and tunable electronic properties. Herein, a photodetector b...

Invited for this month's cover picture is the group of Prof. Xu Xiao at the University of Electronic Science and Technology of China. The cover picture shows a little boy who is celebrating Chinese New Year outdoors with his dog. To keep warm, he is wearing a MXene‐cotton‐based human body thermal management textile, which is also powered by MXene‐c...

Amorphous materials are attractive candidates for fabricating the superconducting nanowire single-photon detectors (SNSPDs) due to their superior tolerance and scalability over crystalline niobium nitride. However, the reduced superconducting transition temperature degenerates both operating temperature and saturation efficiency. Herein, the SNSPD...

The Front Cover shows a little boy celebrating Chinese New Year outdoors with his dog. To keep warm, he is wearing MXene‐cotton‐based human body thermal management textile, which is also powered by MXene‐cotton‐based supercapacitors. More information can be found in the Article by J. Li et al.

Personal body thermal management (PBTM) has shown great potential in the application of artificial skin, smart clothing, and health care for the rapidly developed flexible electronics and “Internet of Things”. However, the heating efficiencies of the previously reported PBTM systems are relatively low with low response rate and high driven voltage,...

Superconducting nanowire single photon detector (SNSPD) plays a significant role in plenty of fields such as quantum information, deep space laser communication and lidar, while the mechanism of the photon response process still lacks a recognized theory. It is prerequisite and essential for fabricating high-performance SNSPD to understand in depth...

The lengthened ion pathway in restacked 2D materials greatly limits the electrochemical performance of practically dense film electrodes (mass loading >10 mg cm⁻²). Typical strategies such as the insertion of nanomaterials and 3D‐structure design is expected to reduce the volumetric capacitance of Ti3C2Tx electrodes, diminishing the dominating adva...

The Cover Feature illustrates 2D arrays of NbN nanocrystals, which are used as stable Li host. Coupled with lithium nickel–manganese–cobalt oxide, a long‐term cycling full Li‐metal battery is realized under practical condition. More information can be found in the Communication by Y. Gogotsi and co‐workers.

Therapeutic nanoparticles are designed to enhance efficacy, real-time monitoring, targeting accuracy, biocompatibility, biodegradability, safety, and the synergy of diagnosis and treatment of diseases by leveraging the unique physicochemical and biological properties of well-developed bio-nanomaterials. Recently, bio-inspired metal nanoclusters (NC...

Superior HER performance of MoS 2 electrocatalyst has been demonstrated due to the low free energy of hydrogen adsorption, electrochemical stability and cost-effectiveness. However, experimental and theoretical studies reveal that the HER activity of MoS 2 remains unsatisfactory due to the inactive basal planes, low intrinsic electronic conductivit...

In article number 2000842, Valeria Nicolosi and co‐workers review the commonly used strategies for manufacturing 3D MXene architectures. Special attention is also given to understand the structure‐property relationships of 3D MXene architectures and highlight their promising applications in electrochemical energy storage and conversion, including s...

The cycle life of rechargeable lithium (Li)‐metal batteries is mainly restrained by dendrites growth on the Li‐metal anode and fast depletion of the electrolyte. Here, we report on a stable Li‐metal anode enabled by interconnected two‐dimensional (2D) arrays of niobium nitride (NbN) nanocrystals as the Li host, which exhibits a high Coulombic effic...

Developing efficient and stable non‐noble electrocatalysts for the oxygen evolution reaction (OER) remains challenging for practical applications. While nickel–iron layered double hydroxides (NiFe‐LDH) are emerging as prominent candidates with promising OER activity, their catalytic performance is still restricted by the limited active sites, poor...

Terahertz (THz) absorption technology is promising in radar stealth, electromagnetic interference (EMI) shielding, and the upcoming 6G communication. However, the most popular metamaterial‐based THz absorbers suffer from complex fabrication process and/or narrowband characteristics. Here, a broadband, lightweight, and hydrophobic THz absorber is re...

Although 2D Ti3C2Tx is a good candidate for supercapacitors, the restacking of nanosheets hinders the ion transport significantly at high scan rates, especially under practical mass loading (>10 mg cm⁻²) and thickness (tens of microns). Here, Ti3C2Tx‐NbN hybrid film is designed by self‐assembling Ti3C2Tx with 2D arrays of NbN nanocrystals. Working...

Two-dimensional (2D) transition metal carbides and/or nitrides (MXenes), by virtue of high electronic conductivity, abundant surface functional groups and excellent dispersion in various solvents, are attracting increasing attention and showing competitive performance in energy storage and conversion applications. However, like other 2D materials,...

Most recently, two-dimensional (2D) transition-metal carbides (MXenes) have been demonstrated to be promising electrocatalysts owing to their unique chemical and electronic properties, e.g., metallic conductivity, high hydrophilicity, and tunable surface terminations. Herein, representative progress achieved in MXenes as hydrogen evolution reaction...

Since its discovery in 2011, the emerging family of two‐dimensional (2D) transition metal carbides, nitrides, and carbonitrides (denoted as MXenes) has shown tremendous promise in the field of energy storages, especially electrochemical capacitors (ECs). The intercalation of foreign species, including but not limited to proton, cations, organic ion...

Developing low-cost and high-performance hydrogen evolution reaction (HER) electrocatalysts is a key research area for scalable hydrogen production from water electrolysis. Here, a hybrid of nitrogen-doped carbon encapsulated Mo2C nanodots on Ti3C2Tx MXene (Mo2C/Ti3C2Tx@NC) is developed through in situ polymerization of dopamine and a Mo precursor...

Transition metal chalcogenides have attracted much attention as high-performance electrocatalysts for hydrogen evolution reaction (HER). Here, we synthesized an efficient HER electrocatalyst of amorphous ruthenium sulfide (A-RuS2), exhibiting an overpotential of 141 mV at the current density of 10 mA cm-2 and a Tafel slope of 65.6 mV dec-1. Experim...

The synthesis of low‐dimensional transition metal nitride (TMN) nanomaterials is developing rapidly, as their fundamental properties, such as high electrical conductivity, lead to many important applications. However, TMN nanostructures synthesized by traditional strategies do not allow for maximum conductivity and accessibility of active sites sim...

The inert basal plane of molybdenum disulfide (MoS2) restrains its further hydrogen evolution reaction (HER) performance. This work attempts ion irradiation to activate inert basal plane of MoS2 nanosheet to improve its electrocatalytic performance. Experimental results demonstrate the sulphur vacancies generated by ion irradiation on the basal pla...

Ultrathin and 2D magnetic materials have attracted a great deal of attention recently due to their potential applications in spintronics. Only a handful of stable ultrathin magnetic materials have been reported, but their high‐yield synthesis remains a challenge. Transition metal (e.g., manganese) nitrides are attractive candidates for spintronics...

Since the demonstration of the unique properties of single-layer graphene and transition metal dichalcogenides (TMDs), research on two-dimensional (2D) materials has become one of the hottest topics, with the family of 2D materials quickly expanding. This expansion is mainly attributable to the development of new synthesis methods to create new mat...

Previous studies revealed that HER activities on MoS2 could be boosted through exotic doping to introduce active centres. However, it is difficult to dope exotic elements into MoS2 with a high concentration due to their different chemical properties from host elements. Here, we theoretically and experimentally optimize the MoS2 edges through substi...

Fluorescent silver nanoclusters (Ag NCs) that are capable of emitting green light have been synthesized using a peptide derived from the C terminal of silk fibroin heavy chain (CSH) via a one-pot, green, and facile synthesis method. The emission was also found to be stable at the excitation wavelength and the fluorescence quantum yield of Ag NCs wa...

Hydrogen evolution reaction (HER) activities could be enhanced on MoS 2 through exotic doping by introducing active centers. In this work, we explored HER activity on MoS 2 edge by alloying isovalent W into MoS 2 nanosheets. The first-principles calculations predicted that optimum HER performance may be achieved with W substituting 50% of Mo in MoS...

Recent developments in electrochemical hydrogen evolution reaction at earth-abundant electrocatalysts and mechanism insights are outlined. Strategies for optimizing catalytic activity are summarized by taking Mo2C family of materials as example.

Exploring low-cost and efficient electrocatalysts based on earth-abundant elements for the hydrogen evolution reactions (HER) is of great importance for the development of clean and renewable energy. In this work, we report a facile self-foaming strategy for synthesis of hierarchically interconnected nitrogen-doped carbon nanosheets (NCNS). The dop...

Invited for this month′s cover is the group of Prof. Lijun Gao in the Soochow Institute for Energy and Materials InnovationS (SIEMIS) at Soochow University. The image shows the overall water splitting catalyzed by a Mo2C-based bifunctional electrocatalyst. The Full Paper itself is available at 10.1002/cssc.201701276.

High-performance and affordable electrocatalysts from earth-abundant elements are desirably pursued for water splitting involving hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In this work, a bifunctional electrocatalyst of highly crystalline Mo2C nanoparticles supported on carbon sheets (Mo2C@CS) is designed towards overal...

MoO2/C nanocomposite has been prepared by simultaneously reducing as-prepared MoO3 nanosheets and introducing an amorphous carbon matrix in the combination of facile hydrothermal and post-annealing processes. MoO2 nanoparticles are uniformly embedded in the carbon framework, resulting in porous nanostructured MoO2/C composite material. The MoO2/C e...

High-performance electrocatalysts for water splitting at all pH values have attracted considerable interest in the field of sustainable hydrogen evolution. Herein, we report an efficient electrocatalyst with a nanocrystalline cobalt phosphide (CoP) network for water splitting in the pH range of 0–14. The novel flexible electrocatalyst is derived fr...

In this letter, we report a facile self-foaming strategy to synthesize Ni3C nanoparticles embedded in porous carbon network (Ni3C@PCN) by rationally incorporating Ni precursor into carbon source. As a novel hydrogen evolution reaction (HER) catalyst, the Ni3C@PCN shows superior catalytic activity with an onset potential of -65 mV, an overpotential...

Bandgap engineering of kesterite Cu2Zn(Sn, Ge)(S, Se)4 with well-controlled stoichiometric composition plays a critical role in sustainable inorganic photovoltaics. Herein, a cost-effective and reproducible aqueous solution-based polymer-assisted deposition approach is developed to grow p-type Cu2Zn(Sn, Ge)(S, Se)4 thin films with tunable bandgap....

Considering the environment protection, “green” materials are increasingly explored for photovoltaics. Here, we developed a kind of quantum dots solar cell based on nitrogen-doped carbon dots. The nitrogen-doped carbon dots were prepared by direct pyrolysis of citric acid and ammonia. The nitrogen-doped carbon dots’ excitonic absorption depends on...

An efficient dual catalyst of molybdenum carbide nanoparticles embedded nitrogen-doped porous carbon nanofibers (Mo2C/NPCNFs) has been developed for hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). The well-aligned and nanoporous identity of the desirable hybrid Mo2C/NPCNFs by a electrospun approach provides the good conductiv...

Due to the good photocatalytic activity, the TiO2@CNTs thin film is highly desirable to apply to the self-cleaning glass for green intelligent building. Here, the TiO2@CNTs thin film has been successfully achieved by polymer-assisted approach of an aqueous chemical solution method. The polymer, polyethylenimine, aims to combine the Ti⁴⁺ with CNTs f...

A facile, self-foaming strategy is reported to synthesize porous, nitrogen-doped carbon nanosheets (N-CNSs) as a metal-free electrocatalyst for oxygen reduction reaction (ORR). Benefiting from the synergistic functions of N-induced active sites, a highly specific surface area and continuous structure, the optimal N-CNS catalyst exhibits Pt-like ORR...

We report an aqueous solution route for directly depositing transparent carbon thin film on SiO2 substrate using polyethyleneimine as carbon precursor. The conductivity of the carbon thin film is calculated to be ~1500 S/cm. Benefiting from film forming ability and permeability of PEI, homogenous and smooth carbon thin films can be deposited onto t...

Thickness-dependent bandgap tunable MoS2 has significant potential applications in electronic and optoelectronic devices. Here, we report an aqueous solution approach to grow thickness-controlled MoS2 films. The thicknesses of the MoS2 films can be readily changed from 50 nm to 2.5 nm, corresponding to bandgaps modulated from 1.50 eV to 1.64 eV. Re...