Yanping Ye

Bio: Yanping Ye is an academic researcher from Jilin Normal University. The author has contributed to research in topics: Borophene & Electrocatalyst. The author has co-authored 2 publications.

Tailoring the d-band center by borophene subunits in chromic diboride toward the hydrogen evolution reaction

Abstract: Transition metal diborides (TMdBs AlB2-type P6/mmm) electrocatalysts have aroused much attention toward the hydrogen evolution reaction (HER), because MoB2 (P6/mmm) exhibits superior catalytic activity. However, the understanding of the activity in the different lattice planes of TMdBs is still limited, which impedes the accurate design of new superior catalyst based on TMdBs. In this work, a borophene subunit was utilized to form AlB2-type CrB2 (P6/mmm) for modulating the d-band center. It was revealed that the d-band center in CrB2 has almost a linear relation with the ΔGH* value in the different lattice planes of metallic Cr and CrB2, and that the modulation of the electronic structure by borophene subunits was more effective at the edge side than in the basal plane of CrB2. Single-phase CrB2 was synthesized via a high pressure and high temperature (HPHT) approach as an electrocatalyst for HER. The performance of CrB2 revealed a higher catalytic activity with overpotentials of 355 and 522 mV at 10 and 200 mA cm−2 in acidic conditions and a Tafel slope of 77.84 mV dec−1. These results indicate that CrB2 is a promising alternative to noble metal-based catalysts, and that modulating the d-band center by borophene subunits is an efficient way to develop novel Cr-based catalysts.

Constructing 1D Boron Chains in the Structure of Transition Metal Monoborides for Hydrogen Evolution Reactions

Abstract: The forms of boron atoms are many and varied in the structure of transition metal borides (TMBs). The form of boron atoms determines the structure, morphology, and properties of borides. Herein, transition metal monoborides (CrB and WB) with different arrangement of one-dimensional (1D) boron chains were synthesized under high pressures and high temperatures. The 1D boron chains between the interlayers of CrB are parallel to one another, while the 1D boron chains between the interlayers of WB are perpendicular to one another. The morphologies of CrB and WB also show large differences due to the difference in 1D boron chain arrangement. As electrocatalysts for hydrogen evolution reactions (HERs), CrB and WB show good catalysis activity and durability. WB has the smallest overpotential (210 mV) and Tafel slope (90.09 mV dec−1), which is mainly attributed to the intercrossing boron chains improving the electrical properties of WB, as well as the 5d electrons of W being more chemically active. The TOF value of WB is 1.35 s−1, proving that WB has a higher intrinsic catalytic activity during HERs. This work provides a data reference for the development of high-efficiency electrocatalysts.

General Synthesis of Transition‐Metal‐Based Carbon‐Group Intermetallic Catalysts for Efficient Electrocatalytic Hydrogen Evolution in Wide pH Range

Abstract: Alloying is a well‐accepted strategy for modulating the electronic structures of catalyst materials. Compared to disordered solid‐solution alloys, intermetallic compounds feature ordered atomic arrangements and provide a unique platform with a rich and diverse resource to study the relationships among chemical composition, atomic structure, electronic structure, and properties. Unfortunately, it is still challenging to synthesize the nanostructures of intermetallic compounds for catalysis research. In this study, a series of intermetallic silicides (PtSi, RhSi, Ru2Si3, IrSi), germanide (Ru2Ge3), and stannides (Ru3Sn7, IrSn2, PdSn3, PdSn2) are rationally designed and constructed through a facile molten‐salt‐assisted route. As an example, the PtSi not only shows highly desirable electrocatalytic properties for the hydrogen evolution reaction (HER) with low overpotentials of 22, 38, and 66 mV at a current density of 10 mA cm‐2 in acidic, alkaline, and neutral media, respectively, but exhibits superior durability, as well as >97% faradic efficiency. The theoretical calculations suggest that the introduction of Si to Pt could weaken the binding energy between Pt and H atoms, which further facilitates the hydrogen generation during the HER process. Further, the findings inspired the authors to develop other kinds of metal‐based carbon‐group intermetallic phases with excellent activity in the HER and beyond.

Surface Modification towards Integral Bulk Catalysts of Transition Metal Borides for Hydrogen Evolution Reaction

Abstract: Transition metal borides (TMBs) are promising catalysts for hydrogen evolution reaction (HER). While the commercially available TMBs indicate poor HER performance due to powder electrode and low activity sites density, optimizing commercial TMBs for better HER performance is urgent. To break through the challenge, a new strategy is proposed to compose integral bulk electrodes with needle surfaces in TMBs. The integral bulk electrodes in TiB2, ZrB2, and HfB2 are formed under high pressure and high temperature (HPHT), and the nanoneedle morphology is constructed by chemical etching. In the three materials, the smallest overpotential is 346 mV at 10 mA cm−2 in the HCl etched bulk TiB2 electrode, which is about 61.9% higher than commercial TiB2 powder. Better performance arises from better conductivity of the integral bulk electrode, and the nano morphology exposes the edge sides of the structure which have high activity site density. This work is significant for developing new kinds of bulk TMBs catalysts.

Efficient Synthesis of WB5-x-WB2 Powders with Selectivity for WB5-x Content.

Abstract: We proposed an efficient method toward the synthesis of higher tungsten boride WB5-x in the vacuumless direct current atmospheric arc discharge plasma. The crystal structure of the synthesized samples of boron-rich tungsten boride was determined using computational techniques, showing a two-phase system. The ab initio calculations of the energies of various structures with similar X-ray diffraction (XRD) patterns allowed us to determine the composition of the formed higher tungsten boride. We determined the optimal parameters of synthesis to obtain samples with 61.5% WB5-x by volume. The transmission electron microscopy measurements showed that 90% of the particles have sizes of up to 100 nm, whereas the rest of them may have sizes from 125 to 225 nm. Our study shows the possibility of using the proposed vacuumless method as an efficient and inexpensive way to synthesize superhard WB5-x without employing resource-consuming vacuum techniques.

Mechanical properties and multifunctionality of AlB₂-type transition metal diborides ^*

Abstract: Abstract Transition metal diborides (TMdBs, P6/mmm , AlB 2 -type) have attracted much attention for decades, due to TMdBs can be conductors, superconductors, magnetism materials, and catalysts. The layered structure caused by the borophene subunit is the source of functions and also makes TMdBs a potential bank of Mbene. However, TMdBs also exhibit high hardness which is not supposed to have in the layered structure. The high hardness of TMdBs arises from covalent bonds of boron–boron (B–B) and strong p – d orbit hybridization of B and TM. While strong B–TM bonds will eliminate the layered structure which may damage the functional properties. Understanding the basic mechanism of hardness and function is significant to achieve optimal TMdBs. This work summarizes the basic properties of TMdBs including hardness, superconductor, and catalytic properties. It can be found that Young’s modulus ( E ) and Shear modulus ( G ) are beneficial for the hardness of TMdBs and the Poisson’s ratio is the opposite. Increasing the atomic radius of TM brings an improvement in the hardness of TMdBs before it reaches the highest value of 1.47 Å, beyond which hardness decreases. Besides, TMdBs also have excellent activity comparable with some noble metals for hydrogen evolution reaction, which is closely related to the d-band center. More importantly, higher valence electron concentrations were found to be adverse to the hardness and superconductivity of TMdBs and greatly affect their catalytic properties. This review is of guiding significance for further exploring the relationship between structures and properties of TMdBs.