Jianwei Zhang

Bio: Jianwei Zhang is an academic researcher from Xi'an Jiaotong University. The author has contributed to research in topics: Carbon nanotube & Laser. The author has an hindex of 14, co-authored 22 publications receiving 464 citations. Previous affiliations of Jianwei Zhang include Qilu University of Technology & Zhejiang University.

Type-II InSe/ g-C3N4 Heterostructure as a High-Efficiency Oxygen Evolution Reaction Catalyst for Photoelectrochemical Water Splitting.

Abstract: We propose a conceptual design of InSe/g-C3N4 van der Waals heterostructure to achieve highly efficient and spontaneous water splitting. InSe/g-C3N4 possesses a direct band gap of 2.04 eV with type-II band alignment, which is beneficial to the separation of electrons and holes and exhibits proper valence and conduction-band positions for the redox reactions of H2O. In addition, the adsorption of multiple water molecules and the changes of free energy on InSe/g-C3N4 have been calculated to understand the oxygen evolution reaction (OER) process of water splitting. The free energies of reaction on three sides are all downhill, and the values of ΔG reduce to about −0.406 eV, indicating that the OER of water splitting is a thermodynamically permissible reaction without the aid of any other substance. Therefore, the water-splitting reaction could be thermodynamically continued using InSe/g-C3N4 as a photocatalyst, which indicates that InSe/g-C3N4 is an excellent candidate for photocatalyst or photoelectronic ap...

The In2SeS/g-C3N4 heterostructure: a new two-dimensional material for photocatalytic water splitting

Abstract: In this work, the structural, electronic and optical properties of the In2SeS/g-C3N4 heterostructure are investigated to explore a highly efficient and spontaneous water splitting photocatalyst by first-principles calculations. The results show that the In2SeS/g-C3N4 heterostructure with a bandgap (Eg) of 2.03 eV is a typical type II semiconductor, which guarantees that the generated electrons and holes can be effectively separated. The potential of the conduction band minimum (CBM) and the valence band maximum (VBM) satisfies the requirements for photocatalytic water splitting. Meanwhile, the In2SeS/g-C3N4 heterostructure has a strong light-absorption ability, and mainly absorbs purple and blue light. In addition, the changes of Gibbs free energy (ΔG) are calculated to understand the oxygen evolution reaction (OER) process of water splitting. Under neutral conditions (pH = 7), the Gibbs free energy continuously decreases during the OER process, verifying the thermodynamic feasibility of water splitting through the In2SeS/g-C3N4 heterostructure. Hence, the In2SeS/g-C3N4 heterostructure is a kind of photocatalyst with excellent performance in the area of photocatalytic water splitting.

Femtosecond Laser Irradiation of Carbon Nanotubes to Metal Electrodes

Abstract: Carbon nanotubes (CNTs) have excellent performance, which means that they could be better electrical conductors. However, the problem of the connection of CNTs to electrodes limits their application. Particularly, improving connection efficiency while ensuring the quality of the connection is a big challenge, because it is difficult to form Ohmic contact between CNTs and electrodes. To address this issue, we propose the use of a femtosecond laser to irradiate the contact surface between the CNTs and the electrodes to obtain a good connection quality and electrical performance. At the same time, since the laser-induced connection acts on all the contact surfaces in the irradiation area, the connection efficiency can be improved, which provides a new idea for the large-scale preparation of the connection.

Nanofabrication with the thermal AFM metallic tip irradiated by continuous laser

Abstract: Based on the near-field optical lithography with the metallic AFM tip irradiated by pulse laser, the nanofabrication is proposed with the thermal AFM tip irradiated by continuous laser. The corresponding electric and thermal fields are calculated and simulated to reveal the mechanism. With the thermal AFM tip, the nanostructures can be fabricated with the thermal melting and mechanical extrusion effects based on the thermal expansion effect of the metallic AFM probe.

Polymeric carbon nitrides and related metal-free materials for energy and environmental applications

Abstract: Carbon nitride polymers have emerged as a new class of materials for a wide range of applications such as photo- and electro-catalysis, sensors, bioimaging and more due to their chemical, photophysical and catalytic properties as well as their low-price, facile synthesis and high stability under harsh chemical conditions. In this review we begin with a broad overview of carbon-based materials, arriving at the focus of this review, polymeric carbon nitrides (CNs). After a brief overview of applications, we delve into their various synthetic methods, with an emphasis on achieving control on the nanoscale features of this intriguing polymeric semiconductor. The main synthetic pathways include co-polymerization at various stages, templating, an ionothermal pathway and harnessing of supramolecular pre-organization, which are discussed in detail along with CN growth and deposition on substrates. Finally, we give our perspectives on the evolution of this field, the current limitations, and elaboration of achievable control over the chemical composition, the electronic structure and the morphology of this family of materials.

Single-Atom Pt Stabilized on One-Dimensional Nanostructure Support via Carbon Nitride/SnO2 Heterojunction Trapping

Abstract: Catalysis with single-atom catalysts (SACs) exhibits outstanding reactivity and selectivity. However, fabrication of supports for the single atoms with structural versatility remains a challenge to...

Direct Z-Scheme Water Splitting Photocatalyst Based on Two-Dimensional Van Der Waals Heterostructures

Abstract: Mimicking the natural photosynthesis in plants, Z-scheme water splitting is a promising strategy to improve photocatalytic activity. Searching for the direct Z-scheme photocatalysts is urgent and the crucial factor for the photocatalytic efficiency is the photogenerated electron-hole ( e-h) recombination rate at the interface of two photosystems. In this report, based on time-dependent ab initio nonadiabatic molecular dynamics (NAMD) investigation, we first report a two-dimensional (2D) metal-free van der Waals (vdW) heterostructure consisting of monolayer BCN and C2N as a promising candidate for direct Z-scheme photocatalysts for water splitting. It is shown that the time scale of e-h recombination of BCN/C2N is within 2 ps. Among such e-h recombination events, more than 85% are through the e-h recombination at the interface. NAMD simulations based on frozen phonon method prove that such an ultrafast interlayer e-h recombination is assisted by intralayer optical phonon modes and the interlayer shear phonon mode induced by vdW interaction. In these crucial phonon modes, the interlayer relative movements which are lacking in traditional heterostructures with strong interactions, yet exist generally in various 2D vdW heterostructures, are significant. Our results prove that the 2D vdW heterostructure family is convincing for a new type of direct Z-scheme photocatalysts searching.

Orienting Z scheme charge transfer in graphitic carbon nitride-based systems for photocatalytic energy and environmental applications

Abstract: In recent years, photocatalysis and photoelectrocatalysis (PEC) have emerged as efficient strategies for facing the energy crisis and environmental pollution. In this regard, the very suitable and exciting material, graphitic carbon nitride (g-C3N4), has drawn spectacular attention because of its fascinating physicochemical properties. However, its practical application in the field of photocatalysis and PEC is still a bottleneck due to its narrow solar energy absorption range, low surface area, which provides less active sites, low electronic conductivity due to deficient CN donor density, poor electron–hole separation efficiency, insufficient redox potentials, and difficulty in the formation of thin films due to its poor dissolution in common solvents. To optimize the redox potential and provide effective spatial charge separation, Z scheme systems are being fabricated by imitating the natural photosynthesis process. In this review, the historical development of g-C3N4-based Z scheme systems is summarized along with their construction, synthesis, and various photocatalytic and PEC applications. g-C3N4-based Z scheme systems, such as the redox mediator solution-phase Z scheme, solid-state Z scheme, and direct Z scheme, and their characterization methods have been discussed briefly. Also, the methodology for the detection of Z scheme charge transfer processes has been explored. Lastly, conclusions and various future perspectives regarding the challenges in the construction and progress of the Z scheme photocatalytic systems are presented.

A rationally designed two-dimensional MoSe 2 /Ti 2 CO 2 heterojunction for photocatalytic overall water splitting: simultaneously suppressing electron-hole recombination and photocorrosion.

Abstract: Electron-hole recombination and photocorrosion are two challenges that seriously limit the application of two-dimensional (2D) transition metal dichalcogenides (TMDs) for photocatalytic water splitting. In this work, we propose a 2D van der Waals MoSe2/Ti2CO2 heterojunction that features promising resistance to both electron-hole recombination and photocorrosion existing in TMDs. By means of first-principles calculations, the MoSe2/Ti2CO2 heterojunction is demonstrated to be a direct Z-scheme photocatalyst for overall water splitting with MoSe2 and Ti2CO2 serving as photocatalysts for hydrogen and oxygen evolution reactions, respectively, which is beneficial to electron-hole separation. The ultrafast migration of photo-generated holes from MoSe2 to Ti2CO2 as well as the anti-photocorrosion ability of Ti2CO2 are responsible for photocatalytic stability. This heterojunction is experimentally reachable and exhibits a high solar-to-hydrogen efficiency of 12%. The strategy proposed here paves the way for developing 2D photocatalysts for water splitting with high performance and stability in experiments.