Development Strategies in Transition Metal Borides for Electrochemical Water Splitting

Abstract

Electrochemical water splitting is a feasible method for producing environmental benignity energy of hydrogen, while high price and low availability on the earth of noble electrocatalysts constrain their global-scale application. Transition metal borides (TMBs) have displayed unique metalloid characteristic and outstanding performance for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in the last few decades. Herein, recent developments of the TMBs for HER and OER are summarized. Initially, the impact factors and relevant evaluation of electrocatalytic performance are described, that is, overpotential, Tafel slope and exchange current density, stability, faradaic efficiency, turnover frequency, mass and specific activities. Moreover, the optimization strategies of borides are emphasized, which principally include coupling with effective substrates, elemental doping, phase modification, interfacial engineering, and morphology control. Finally, in order to reach the goal of application, the remaining challenges and perspectives are given to point out a direction for enhancing the performance of borides.

Surface‐Decorated High‐Entropy Alloy Catalysts with Significantly Boosted Activity and Stability

“…The voltammograms exhibit well‐established features of adsorption and desorption of the H species on Pd sites. However, it is known that the hydrogen adsorption method is less reliable for ECSA [ 70 ] assessment of Pd‐based electrocatalysts due to the formation of bulk Pd hydride. [ 71 ] Instead, the ECSAs of these catalysts were evaluated by determining the Coulombic charge associated with the reduction peak of the Pd oxidation layer on the surface during the negative CV scan at ≈0.71 V versus RHE, as summarized in Table 1 .…”

Regulation of Electrocatalytic Activity by Local Microstructure: Focusing on the Catalytic Active Zone

“…Due to the characteristics of boron as a quasi-metallic element, boron atoms exhibit abundant covalent bond modes in different boride lattice, which provides a variety of ways to construct the local microstructure. [50] Chemistry-A European Journal ethane sponge by electroless plating (BÀ FeNi@HS). [51] B and Ni cooperated to change the electronic structure of Fe and built the active zone together.…”

“…In addition to the high‐valence metal, light elements doping (such as N, B, S) is also an effective method to improve the electronic structure of 3d transition metals and to construct local microstructure active zones to improve the intrinsic catalytic activity of transition metals. Due to the characteristics of boron as a quasi‐metallic element, boron atoms exhibit abundant covalent bond modes in different boride lattice, which provides a variety of ways to construct the local microstructure [50] . Hao et al.…”

Boosting the overall electrochemical water splitting performance of pentlandites through non-metallic heteroatom incorporation

“…Along this line, transition metal-rich inorganic materials have recently emerged as vital and important alternatives to precious metal electrocatalysts because of their rich stoichiometric flexibility, high stability, achievable pseudo-metallic conductivity as well as the ease of preparation from cheap and readily available starting materials ( Dou et al., 2019 ; Siegmund et al., 2020 ). Within this family of metal-rich inorganic materials, the transition metals are commonly accompanied by a variety of main group elements forming, e.g., oxides ( Simon et al., 2021 ; Zakaria et al., 2015 ), sulfides ( Bentley et al., 2018 ; Smialkowski et al., 2021 ; Tetzlaff et al., 2021 ), carbides ( Zakaria et al., 2016 , 2017 ), borides ( Yao et al., 2021 ), phosphides ( Pu et al., 2020 ), selenides ( Desalegn et al, 2022 ; Feng et al., 2019 ; Xia et al., 2020 ), and double layered hydroxides ( Sun et al., 2020 ). Despite the almost infinite number of conceivable materials, there is still no real competitor to replace current electrocatalysts in AEL and PEM technologies and achieve the efficiency and stability needed for large-scale practical applications to date ( Grigoriev et al., 2020 ; Siegmund et al., 2021 ).…”