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.

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

Low electrical conductivity and poor accessibility of MoS2 reaction sites raise great challenges in maximizing the triple-phase-boundary (TPB) sites of MoS2-based electrodes and minimizing ohmic losses for efficient hydrogen evolution reaction (HER) in practical proton exchange membrane (PEM) water electrolysis. Herein, we report a scalable hydrothermal approach to fabricate ionomer-free integrated electrodes with engineered 1 T-2 H heterophase and defect-rich MoS2 nanosheets (MoS2NSs) in-situ grown onto the carbon fiber paper (CFP). With an ultralow loading of 0.14 mg/cm2, a small voltage of 2.25 V was obtained at 2000 mA/cm2 in a practical cell with Nafion115 membrane, which outperforms all previously reported high-loading non-precious catalyst-based electrodes. Impressively, it shows 44 times higher mass activity than a high-loading and ionomer-mixed MoS2 assemblies electrode. This work builds a bridge from catalyst optimization to electrode fabrication and provides a promising direction for improving intrinsic catalytic activity, electrode conductivity and stability for practical PEM water electrolysis. 

http://manuscript.elsevier.com/S092633732200399X/pdf/S092633732200399X.pdf

MoS2 nanosheet integrated electrodes with engineered 1T-2H phases and defects for efficient hydrogen production in practical PEM electrolysis

Restructuring electronic structure via W doped 1T MoS2 for enhancing hydrogen evolution reaction

Interfacial electronic engineering of carbon encapsulated Co5.47N-WO2 for boosting overall water splitting

Effects of Platinum Group Metals on MoS2 Nanosheets for a High-Performance Hydrogen Evolution Reaction Catalyst

Modifying microscopic structures of MoS2 by high pressure and high temperature used in hydrogen evolution reaction

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.

Jiashi Rong

Papers

Modifying microscopic structures of MoS2 by high pressure and high temperature used in hydrogen evolution reaction

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